Advances in Neurodevelopmental Disorders https://doi.org/10.1007/s41252-023-00366-x ORIGINAL PAPER Advances and Challenges in the Assessment of Executive Functions in Under 36 Months: a Scoping Review Valeria Escobar‑Ruiz1 · Pedro I. Arias‑Vázquez2 · Carlos A. Tovilla‑Zárate2 · Eduardo Doval1 · Maria C. Jané‑Ballabriga1 Accepted: 29 September 2023 © The Author(s) 2023 Abstract Objectives Neurodevelopmental disorders present deficits in executive functions (EFs). Before 36 months old, EFs act as basic abilities that allow adequate executive functioning at later ages. Three basic EFs are assessable before the child reaches 36 months old: working memory, inhibition, and cognitive flexibility. This review aims to provide an overview of the progress and difficulties in assessing these three basic executive functions before children reach 36 months old. Methods Four databases were systematically searched without time or language limitations. The selection process was done using a PRISMA flowchart for scoping reviews. Sixteen studies were included, all in English and published between 2004 and 2021. Results Out of 277 studies, 16 met the inclusion criteria. The general data of the studies were summarized, such as sample age, type of study, measurement features, types of EFs assessed, task names, internal structure, reliability, and main contri- butions. The findings on available tasks and scales, factor structure, biological and environmental factors, and the variables influencing EFs before 36 months old are described. Conclusions Multiple factors influenced the evolution of EFs. The unidimensional model seems to better explain EFs before 36 months old. Expanding psychometric research with large samples and studying samples of children with symptoms at risk for neurodevelopmental disorders may help to improve the measurement of EFs before 36 months old. Keywords Executive functions · Working memory · Inhibition · Cognitive flexibility · Infant · Toddlers Executive functions (EFs) can be defined as a set of cogni- (Sparrow, 2012). Current research has identified two key tive functions that control complex, goal-directed thoughts moments in the development of EFs: first, before 36 months and behaviors (Zelazo, 2015), although there is no consensus old, when EFs operate as basic abilities that allow adequate on a single definition. EFs involve multiple domains devel- executive functioning at later ages, and, second, after 36 oped throughout life. There are three basic EFs reported in months old, when these abilities have become coordinated the literature that can be measured before 36 months old: with each other and with other skills (García-Molina et al., working memory (WM), inhibition, and cognitive flexibility 2009). Moreover, between late infancy and early toddler- (CF) (García-Molina et al., 2009; Hoskyn et al., 2017). hood, EFs are not functionally silent (García-Molina et al., The study of EFs had an upswing in the 90s, based mainly 2009). Studies suggest that this period may be a sensitive on adult samples, and at that time, it was considered that stage for EF development (Diamond, 2002; Zelazo et al., these functions emerged at ages later than those known now 2003). Furthermore, there is evidence that EFs can be improved if interventions are made at early ages, especially during periods of high relative plasticity of the prefrontal * Valeria Escobar‑Ruiz valeria.escobar@autonoma.cat cortex (PFC) (Diamond, 2015; Zelazo, 2020). The PFC is the brain region responsible for executive 1 Universitat Autònoma de Barcelona, Belaterra, Barcelona, functioning. After birth, there is a stage of rapid synapse España production with significant synaptic density increases in 2 División Académica Multidisciplinaria de Comalcalco, the first year of life. Subsequently, between 2 and 3 years Universidad Juárez Autónoma de Tabasco, old, peaks in synaptic density occur, and the synaptic Comalcalco, Tabasco, México 13 Vol.:(0123456789) Advances in Neurodevelopmental Disorders pruning begins at the age of seven. Adult levels of synap- This review focuses on these three basic EFs (WM, tic density are reached in mid-adolescence (García-Molina inhibition, and CF), which emerge and develop at differ- et al., 2009). The developmental trajectory of synaptogen- ent times and range even before the age of 36 months old esis of PFC appears to contribute to EF abilities (Hoskyn (Garon et al., 2008). WM is understood as the ability to et al., 2017). Moreover, alterations in PFC white matter store and manipulate information for a short period, which have been observed in people with autism spectrum dis- allows updating and replacing irrelevant information, that order (ASD) and attention deficit hyperactivity disorder is, the capacity to cognitively retain information that is no (ADHD) (Ameis et al., 2016). Other conditions such as longer directly perceived to manage it in some way for a phenylketonuria, premature birth, hypothyroidism, Down specific purpose (Demetriou et al., 2019). The WM emerges syndrome, school learning difficulties, and behavioral con- between 7 and 12 months old, and usually, the task to assess trol have also been associated with executive dysfunction it considers both the child’s response time when looking at (Blanco Villaseñor et al., 2010). Although the literature an object in one place and the ability to maintain attention reports a strong association between neurodevelopmental on the object (even when not seeing it) (Díaz & Guevara, disorders and EF difficulties, it is important to clarify that 2016). Inhibitory control is defined as the ability to con- not all people with neurodevelopmental disorders have EF trol attention, behaviors, thoughts, and emotions to provide deficits and likewise not all people with EF deficits have a a specific response. It also requires the child to suppress neurodevelopmental disorder. external stimuli that could distract him from the objective The strong link between neurodevelopmental disorders (Díaz & Guevara, 2016). Simple forms of inhibitory control and EF deficits has prompted research in adolescents and emerge around the middle of the first year (García-Molina children (Hunter & Sparrow, 2012), but neurodevelopmen- et al., 2009). The theoretical perspective of EFs is not the tal disorders before 36 months old have been difficult to only one that explains inhibitory control. The temperament diagnose as sample collection is challenging. The main approach focuses mainly on socio-emotional development problem is that the term EF is a complex construct with a and also shows inhibition behaviors. As a consequence, EFs wide variety of theoretical models and processes that influ- and temperament have a large amount of empirical evidence ence the standards to assess them (Demetriou et al., 2019; suggesting a strong relationship between them (Gagne et al., Soto et al., 2020). A scoping review is highly relevant to 2021; Rocha et al., 2019). Finally, CF is defined as the abil- summarize the current literature in the assessment of EFs ity to switch the perspective given to a problem to adapt to under 36 months old. new demands, rules, or priorities (Díaz & Guevara, 2016). In recent years, the study of EFs at early ages has gener- At 24 months old, there is a significant increase in the abil- ated some controversy. Firstly, researchers consider that ity to perform switching tasks through verbal instructions the initial sightings of EFs are very poorly developed in (Deák, 2004). that age range and can be considered as embryonic forms The literature reports several different tasks to assess of executive functioning (García-Molina et al., 2009). Sec- these three basic EFs at early ages, but due to their valid- ondly, it is a concept that is difficult to define and measure ity and reliability, some of them have been used more fre- (Blair et al., 2005). Until the 2000s, from a neuropsycho- quently. For example, to measure WM, the two frequently logical point of view, it was considered that adequate mod- reported tasks are spin-the-pots and hide-and-seek tasks els with predictive capacity were not available. Therefore, (Bernier et al., 2010; Hughes & Ensor, 2005). One task the description and conceptualization process for EFs was used to assess inhibition is the prohibition task. It consists previously based on theories and assumptions that hin- of measuring the time in which the child manages to con- dered their objective conception (Tirapu-Ustárroz et al., trol the impulse to take a prohibited object. This task has 2002). been used on children as young as 14 months old (McHarg Currently, some models have been developed to explain et al., 2020). Regarding CF, various tasks have been used the importance of EFs at these early ages for later develop- for its assessment at such early ages (Johansson et al., 2014; ment (Garon et al., 2008; Rose et al., 2012). One of the most McHarg et al., 2020). The most relevant is the A-not-B task, reported EF models is the unity and diversity model (Miyake which is related to object permanence development (Piaget, et al., 2000) which determined three moderately correlated, 1954). The task involves hiding an object under a location but separable EFs, namely, WM, inhibition, and CF. The “A” within the infant’s reach and then allowing the infant to unity and diversity model has been used mainly in adult search for the object, repeating this several times to ensure samples, while in children samples and adolescents, studies that the infant can find the object successfully. Afterward, suggest greater unidimensionality of EFs (Karr et al., 2018). the object is moved to a location “B” that is also within easy In addition, some studies showed a better fit with a bidimen- reach for the infant. This task assesses the ability to find the sional structure (Scionti & Marzocchi, 2021). object in a new location. In different studies, adaptations of this task contemplate resistance to delay, which implies that 13 Advances in Neurodevelopmental Disorders examiners are controlling when the infant can search for in assessing the three basic EFs (WM, CF, and inhibitory the object. The A-not-B task has shown consistency with control) in infants younger than 36 months old. The little electroencephalographic data, functioning as a valid indica- scarce information existing in the field of assessment and tor of early cognitive processing of the frontal lobe from 8 the limited studies attempting to assess and generate tangible months onwards (Bell, 2012). In this task, resistance to delay measurements of EFs at early ages (Wiebe et al., 2010), as increases with age; that is, at early ages, the child may show well as the difficulty of establishing a specific assessment executive functioning responses, as long as the time of delay method at these ages (questionnaire for parents and teachers, is appropriate for the infant’s age. As the children grow, they specific tasks, etc.), make necessary detailed and methodical can manipulate and transform this information (between 15 research to provide reliable and evidence-based techniques and 30 months old). For example, before 36 months old, allowing for the correct identification of difficulties in the children depend on stimuli from the environment, and their EFs before 36 months old. responses tend to be stereotyped, rigid, and oriented to the present (García-Molina et al., 2009). Currently, few existing tests assess EFs at early ages. Method The most popular test is the Behavior Rating Inventory of Executive Function-Preschool Version (BRIEF-P). It is a The present scoping review was conducted following the specific EF test that includes an assessment of inhibition, five-stage process proposed by Arksey and O’Malley (2005). flexibility, emotional control, WM, and planning and organi- Each stage is described below. zation. The BRIEF-P generates four indices (global, inhibi- Stage 1. Identifying the research question: The present tory self-control, flexibility, and emergent metacognition) study aims to answer two questions: What advances have and two validity scales (inconsistency and negativity). It is been reported for the evaluation of the three basic EFs in applied to children ranging from 2 years old up to 5 years children under 36 months old? And likewise, what chal- and 11 months old. This test is an indirect measure based lenges have been reported for this age range? on the child’s behavior and answered by the parents or car- Stage 2. Identifying relevant studies: The search was egivers and teacher. It takes 10 to 15 min to complete. The carried out in the PubMed, Scopus, and Web of Science first BRIEF-P version was in English (Gioia et al., 2000). databases, as well as the digital library of the Autonomous A Spanish version is available, with scales for the Spanish, University of Barcelona. The search terms used were devel- Argentine, and Mexican populations (the last only includes opment, infant, executive functions, working memory, inhi- 3 to 5 years age group). Additionally, the BRIEF-P also has bition or inhibitory control, and shifting or cognitive flex- versions in Catalan and Euskera (Gioia et al., 2016). ibility. The search commands for each database are shown Another commonly used test is the Stanford-Binet Intel- in Table 1. ligence Scale, fifth edition. The test is in English and has Stage 3. Study selection: Original full-text studies were scales in the US population (Roid & Pomplun, 2012). included without date or language limits. Research, with Although it is an intelligence test, some subtests can be assessment by cross-sectional and longitudinal studies of used to measure EFs, specifically for verbal and non-verbal basic EFs (WM, inhibition, and CF) before 36 months old WM factors (Hoskyn et al., 2017). A battery with three EF in a population with typical development, was considered. tasks (WM, inhibition, and CF) was created by Garon et al. Additionally, reviewed literature included ADHD, ASD, (2014) and applied to children aged 18 months and 5 years or other risk factors such as premature birth but without old. These authors assessed WM for holding-in-mind and any other underlying pathology. Systematic reviews, con- updating-in-mind, CF for positive and negative change task ference abstracts, and thesis dissertations were excluded. sets, and inhibition for simple and complex behaviors. The selection of the studies was carried out in three phases: Understanding executive functioning at an early age is (1) The title and abstract of the studies were examined, (2) difficult due to the diversity of variables that influence its studies selected for full-text review were independently development. Additionally, biological and environmental assessed, and (3) the reviewers met to reach a consensus factors are associated with the correct performance of EFs on the included studies. The considered exclusion criteria (Hughes & Devine, 2019; Jirout et al., 2019; Ronan et al., were for duplicate studies, age samples (over 36 months old), 2020). These factors complicate the measurement of EFs and type of study, and measurement features. Reasons for exclu- the adequate construction of tests to assess them at an early sion were based on the assessment of EFs after 36 months age. This review also includes results related to variables (despite other variables being assessed before 36 months that interfere with the development and measurement of EFs old), samples with an underlying pathology, and assessments in children under 36 months old. that consider temperament instead of EFs (due to the strong The present study offers a scoping review of the litera- relationship with inhibition). The selection process is shown ture providing an overview of the progress and difficulties in Fig. 1 through a PRISMA flowchart for scoping reviews. 13 Advances in Neurodevelopmental Disorders Table 1  Commands used for the search in each database Database Commands PubMed ((((development) AND (infant)) AND (executive function) AND (working memory)) AND (inhibition OR inhibitory control)) AND (shifting OR cognitive flexibility) Web of Science TS=((((Development and infant) and working memory) and inhibition) and shifting) TS=((((Development and infant) and working memory) and inhibitory control) and shifting) TS=((((Development and infant) and working memory) and inhibitory control) and cognitive flexibility) TS=((((Development and infant) and working memory) and inhibition) and cognitive flexibility) Scopus TITLE-ABS-KEY ((((development AND infant) AND “working memory”) AND inhibition) AND shifting) TITLE-ABS-KEY ((((development AND infant) AND “working memory”) AND “inhibitory control”) AND shifting) TITLE-ABS-KEY ((((development AND infant) AND “working memory”) AND “inhibitory control”) AND “cognitive flex- ibility”) TITLE-ABS-KEY (((( development AND infant) AND “working memory”) AND inhibition) AND “cognitive flexibility”) Other resources ((((development AND infant) AND “working memory”) AND inhibition) AND shifting) ((((development AND infant) AND “working memory”) AND “inhibitory control”) AND shifting) ((((development AND infant) AND “working memory”) AND “inhibitory control”) AND “cognitive flexibility”) ((((development AND infant) AND “working memory”) AND inhibition) AND “cognitive flexibility”) Fig. 1  PRISMA-ScR flowchart 13 Advances in Neurodevelopmental Disorders Stage 4. Charting the data: The data are presented in tasks were assessed as composite scores (including the three tables, all revised and organized in consensus by two basic EFs) and classified under different names (e.g., conflict reviewers. General information about the studies is included tasks or cognitive executive function). Table 2 includes all (e.g., authors, year, ages of participants, type of EFs, task this information organized by authors, type of EFs, task’s names, main results, factor analysis, and reliability). The name including a citation of the study from which the task results were summarized in four relevant topics to show the was obtained, and assessment ages. The following subsec- advances and challenges of measuring EFs before 36 months tion describes the task features for each EF (i.e., WM, inhibi- old. tion, and CF). Also, a battery and a questionnaire extracted Stage 5. Collecting, summarizing, and reporting the from the literature are described in this review. results: The findings are shown in Tables 2 and 3. All the 16 studies included were published between 2004 and 2021 Working Memory Tasks in psychology, development, and childhood journals. Ten studies were cross-sectional, six were longitudinal, and all The WM tasks applied at earlier ages were two: hide the were published in English. The samples came mostly from pots (or similar names) and hide and seek. These tasks were a typical development population, one from a population applied up to the age of 18 months (Garon et al., 2014; Treat with ASD, one from institutionalized children, and one from et al., 2019), and both tasks required the child to find a toy bilingual children. Subsequently, the analysis of the results under or behind some other object. The tools for hiding regarding the advances and challenges in the assessment of the toy may be different, but the goal (finding an object) is EFs under 36 months old was divided into four topics: (1) always the same. For example, a piece of fabric covers the available tasks and scales, (2) the unidimensional model of toy for a waiting time (determined by the examiner) making EFs, (3) variables related to EF measurement, and (4) bio- it more complex to find the toy. As in most assessments, logical and environmental factors related to EF development. several practice trials are performed to proceed with the test. A score is obtained by counting the child’s mistakes. Three studies used the spin-the-pots task, with a simi- Results lar goal to hide the pots but with more pots and at older ages (Pozzetti et al., 2014; Treat et al., 2019). The task was The search identified 277 studies (Fig. 1), of which 261 were applied with eight or more pots for children aged 28 months excluded. Hence, only 16 studies that assessed basic EFs or older. Pozzetti et al. (2014) created an easier version using under 36 months old were considered (see Tables 2 and 3). six pots for younger infants (< 24 months old). Another sim- Studies include diverse samples of children, such as those ilar task is the three-box task that was applied by McHarg born premature or extremely premature, post-institutional- et al. (2020) for 14-month-old children. These tasks require ized, infants with ASD, bilingual, monolingual, and typi- placing several visually distinct containers on one tray. The cally developing. Other studies included samples consisting examiner invites the child to place objects under the pots in of the mother-child dyad or the whole family. The sample’s a manner that left two pots empty. A piece of fabric is placed ages range from 5 to 74 months old, although only findings to cover the tray, and the tray is then rotated. Subsequently, in children younger than 36 months old were considered for the tray is uncovered, and the child is asked to choose one this review. of the pots that contain an object. This is performed until Four topics describe the most relevant findings. The first the child finds a given number of objects or fails a maxi- explains the WM, inhibition, and CF tasks, as well as the mum number of spins. The way of scoring differs among two scales reported in the studies. The second addresses evi- researchers: Some count errors and perseverations and oth- dence suggesting that the unidimensional model can explain ers only whether or not the child achieves what is expected better all three basic EFs at these early ages. The third topic as a dichotomous measure. details the variables that may influence the measurement of Other tasks described in the reviewed studies were multi- the basic EFs. The last topic summarizes the findings of the location task, find the toy, multi-location multi-step, delayed variables that demonstrated an influence on the development alternation, six boxes, and visual attention. Nevertheless, of the EFs, to understand the complexity of measuring EFs its procedures and goals are similar to the tasks described at early ages. above. Furthermore, studies revealed that performance on WM tasks improves with age. Available Tasks and Scales Inhibition Tasks For this first topic, sixty-six tasks were examined from the 16 reviewed studies, some of which consisted of an adapta- To assess inhibition, tasks were identified in which the chil- tion of tasks described in other studies (see Table 2). Some dren are required to wait for a reward after a delay (inhibiting 13 Advances in Neurodevelopmental Disorders Table 2  Executive functions, tasks, and assessment ages by study Authors EF Task’s name Sample Espy et al. (2004) In Delayed response (Jacobson, Wolfe & Jackson 1935) n = 66 TD and 30 PT children WM Delayed alternation (Espy, Kaufmann, McDiarmid et al., 24 to 60 1999) months old CF Spatial reversal (Kaufmann, Leckman & Ort, 1989) CF Spatial reversal with irrelevant color cues (Kaufmann, Leck- man & Ort, 1989) WM Six boxes (Diamond et al., 1997) WM Visual attention (NEPSY-A, Korkman et al., 1998) In Children continuous performance task (C-CPT) (Kerns & Rondeau 1998) In Statue (NEPSY subtest, Korkman et al., 1998) In Self-control (Lee, Vaughn, & Kopp, 1983) Bernier et al. (2010) CT Hide the pots (adapted from Hughes and Ensor (2005)) n = 80 mother-infant dyads CT Categorization (adapted from Carlson et al. (2004)) 18 to 26 months old CT Spin the pots (Hughes & Ensor, 2005). IC Delay of gratification (Kochanska et al., 2000). CT Shape Stroop (Kochanska et al., 2000). CT Baby Stroop (adapted from Hughes & Ensor, 2005). Matte-Gagné and Bernier (2011). CT Spin the pots (Hughes & Ensor, 2005) n = 53 mother-infant dyads IC Delay of gratification (Kochanska et al., 2000) 24 to 36 months old CT Shape Stroop (Kochanska et al., 2000) CT Baby Stroop (adapted from Hughes and Ensor (2005)) CT Day/night (Gerstad et al., 1994) CT Dimensional change card sort (DCCS) (Zelazo, 2006) CT Bear/dragon (Reed et al., 1984) Bernier et al. (2012) CT Spin the pots (Hughes & Ensor, 2005) n = 62 families IC Delay of gratification (Kochanska et al., 2000) 24 to 36 months old CT Shape Stroop (Kochanska et al., 2000) CT Baby Stroop (adapted from Hughes and Ensor (2005)) CT Bear/dragon (Reed, Pien & Rothbart, 1984) CT Day/night (Gerstad, Hong & Diamond, 1994) CT Dimensional change card sort (DCCS) (Zelazo, 2006) IC Delay-of-gratification task (Kochanska et al., 2000) Hostinar et al. (2012) CF Dimensional change card sort (DCCS) (Zelazo, 2006) n = 60 PI children and 30 NA 28 WM Spin the pots (Hughes & Ensor, 2005) to 48 months old In Delay of gratification (Mischel, Shoda & Rodriguez, 1989) Cuevas and Bell (2014) CS A-not-B with invisible displacement (Morash & Bell, 2011) n = 201 children Tongue task (Kochanska, Murray, & Harlan, 2000; Wolfe & 24, 36, and 48 months old Bell, 2007) Day/night (Gerstadt, Hong, & Diamond, 1994) Simon says (Carlson, Moses, & Breton, 2002; detailed in Wolfe & Bell (2007)) Dimensional change card sort (DCCS) (Zelazo, Frye, & Rapus, 1996) Visual search (Espy & Bull, 2005; Korkman, Kirk, & Kemp, 1998) Garon et al. (2014) WM Hide and seek (created by the authors Garon et al. (2014)) n = 261 In Tricky box (created by the authors Garon et al. (2014)) children 18-67 months old CF Flap book (created by the authors Garon et al. (2014)) Johansson et al. (2014) CF A-not-B task (Piaget, 1954) n = 40 infants 10 months old 13 Advances in Neurodevelopmental Disorders Table 2  (continued) Authors EF Task’s name Sample Pozzetti et al. (2014) WM Spin the pots (Hughes & Ensor, 2005) n = 72 EPT and 73 FT children 24 months old In Snack delay (Kochanska et al., 1996; Kochanska et al., 2000) CF Reverse categorization (adapted from Carlson et al. (2004)) CS Multi-location multi-step (modified A-not-B task by Zelazo et al. (1998)) Crivello et al. (2016) CF Reverse categorization task (Carlson, 2005; adapted from n = 49 BL and 43 ML children Carlson et al., 2004) 31 months old In Shape Stroop task (Carlson, 2005; adapted from Kochanska et al., 2000) In Gift delay task (Carlson, 2005; adapted from Kochanska et al. (2000)) WM Multi-location task (Carlson, 2005; adapted from Zelazo et al. (1998)) Marcovitch et al. (2016) CF Looking A-not-B task (Cuevas & Bell, 2017; scoring proce- n = 390 dure based on Bell & Adams (1999)) 5 months old infants Pauen and Bechtel-Kuehne (2016) CF Shape and color sort (adapted version of the DCCS of Zelazo n = 93 children study 1 (2006)) n = 62 children study 2 In Forbidden cookie (inspired by the snack delay task by 22 to 24 months old Kochanska et al. (2012)) WM Find the toy (adaptation of the hide-the-pots task by Bernier et al. (2010) and Hughes and Ensor (2005)) Garon et al. (2018). WM Hide and seek (Garon et al., 2014) n = 34 children In Tricky box (Garon et al., 2014) with ASD and 255 TD 18 to 74 months old CF Flap book (Garon et al., 2014) Treat et al. (2019) WM Hide-the-pots task (adapted by Bernier et al. (2010); from n = 55 mother-child dyads Hughes and Ensor (2005)) 18 to 40 months old WM Spin-the-pots task (Bernier et al., 2010; Hughes & Ensor, 2005) CF Categorization task (adapted from Carlson et al. (2004) by Bernier et al. (2010)) CF Reverse categorization task (Carlson, 2005) In Delay-of-gratification task (Kochanska et al., 2000) McHarg et al. (2020) In Prohibition task (Friedman, Miyake, Robinson, & Hewitt, n = 416 FB infants 14 months old 2011) WM Three boxes task (Miller & Marcovitch, 2015) CF The ball run task (based on the trucks task developed by Hughes and Ensor (2005)) Hendry and Holmboe (2021) CS and Early Executive Functions Questionnaire (EEFQ) 31 items n = 486 children regula- 8–30 months old tion All references in the table are cited in the reviewed studies WM working memory, In inhibition, CF cognitive flexibility, CT conflict tasks, CS composite score (including WM, In, CF), IC impulsive con- trol, TD typical development, PT preterm, PI post-institutionalized, NA not adopted, EPT extremely preterm, FT full term, BL bilingual, ML monolingual, ASD autism spectrum disorder, FB firstborn their behavior) or to inhibit a distracting stimulus to fol- it to them. In some studies, the child is asked to wait for a low instructions correctly. The tasks in which the child was bell to ring, for the examiner to return, or for permission to required to expect a reward after a delay were gift delay task, take the object. As a quantifying assessment, the time the delay-of-gratification task, forbidden cookie, snack delay, child can control the behavior is measured (Crivello et al., delayed response, prohibition task, and self-control tasks. 2016; Treat et al., 2019). An alternative inhibition task, the Basically, in these tasks, the children are offered a food or statue task (Espy et al., 2004), also aims for the child to object that they like and are instructed to wait before giving achieve control of a prohibited behavior (e.g., moving) but 13 Table 3  Factor analysis, internal structure and reliability, other variables, and main results by study Authors Internal structure and reliability Other variables included Main results 13 Espy et al. (2004) Three factors were extracted that explain 60.82% Emerging mathematical abilities and intellectual WM and inhibitory control predict early arithmetic of the variance, (1) WM explained 26.59%, (2) ability competence (controlling for child age, maternal inhibitory control 19.39%, and (3) CF 14.84% of education, and the child’s vocabulary). Inhibitory the variance. Reliability was not reported. control contributed to preschool math skills, even removing the influence of WM and In. Bernier et al. (2010) Two factors were obtained that explain 64.7% of Maternal sensitivity, maternal mind-mindedness, Maternal sensitivity, mind-mindedness, and the variance; (1) impulse control and (2) conflict maternal autonomy support, and general cogni- autonomy support were related to the child’s EFs. EFs. Two averaged standardized scores were tive ability Autonomy support was the strongest predictor at calculated. Reliability was not reported. each age, independently of general cognitive abil- ity and maternal education. Parent-child relation- ship influences the development of self-regulatory abilities in the child. Matte-Gagné and Bernier (2011) Two factors were obtained that explain a total Maternal autonomy support and child’s expressive Maternal autonomy support was related to the of 61.7% of the variance; the factors are (1) vocabulary child’s expressive vocabulary, conflict EF, and impulse control and (2) conflict EFs. Low reli- impulse control. The child’s language mediated ability on all tasks was obtained. the association between maternal autonomy sup- port and child impulse control, but that was not the case with conflict EFs. Bernier et al. (2012) Two factors were extracted that explain a total Maternal: responsiveness, mind-mindedness, Parent behavior composite score and child attach- of 64.8% of the variance, these factors are (1) and autonomy support. Quality of parent-child ment are related to child performance on conflict conflict EFs and (2) impulse control. Reliability interactions. Children: secure attachment and EF tasks. The child’s secure attachment is related was not reported. receptive verbal ability to conflict EFs at 3 years old. The child’s verbal abilities, previous EFs, socioeconomic status, and parental behavior suggest that secure attachment influences the development of executive control. Hostinar et al. (2012) A single common factor was identified that IQ, pre-adoptive experiences, and the institution’s IQ was negatively correlated with the length of explained 70.8% of the variance. The tasks were physical and social features institutional care. The adopted sample obtained highly correlated. The three measures were an association between EFs and measures of early merged into one composite EF score. Reliability deprivation controlling IQ (less time spent in the was not reported. biological family before placement in an institu- tion and lower quality of physical/social care in institutions), suggesting that this predicts a poorer performance on EFs. Cuevas and Bell (2014) One component in 24, 36, and 48 months old Care at 5 months. Verbal ability Short lookers show higher EF composite scores in (explained 55%, 50%, and 45% of the variance comparison with long lookers, even after control- respectively). A composite z-score was obtained ling for verbal ability. Attention style at 5 months that explained 45%. Cronbach’s interrater reli- old is related to EF scores from 24 to 48 months ability in all tasks is more than .90. old. Garon et al. (2014) WM, CF, and In obtained 2 factors each and Cognitive ability All EF measures correlated positively with age in explained 39.09%, 42.69%, and 53.65% of the months and mental age, showing sensitivity to age variance respectively. Reliability was .70 to .93 differences. in all tasks. Advances in Neurodevelopmental Disorders Table 3  (continued) Authors Internal structure and reliability Other variables included Main results Johansson et al. (2014) Factorial analysis and reliability are not reported. Temperamental measures: activity level and atten- 10-month-olds show individual differences in Agreement with Cohen’s Kappa between coders tion A-not-B task performance, reflecting variation was .86 and .81 in both reaching and looking in temperamental activity level, and maturity of responses, respectively. short-term/WM, In, and CF. It also concludes that looking response may be less cognitively demand- ing than reaching response. Pozzetti et al. (2014) Three final factors are extracted: CF, In, and WM Cognitive ability and psychomotor function. Provided a broad assessment of 3 basic EFs. explained 19.18%, 16.92%, and 15.76% of the Questionnaire for parents and medical records Preterm infants without significant brain injuries variance respectively. All tasks show limited showed some weaknesses in CF compared to con- psychometric validity and reliability. trols. CF in preschool ages could be a precursor Advances in Neurodevelopmental Disorders of deficit in these EFs in older ages. WM did not show differences. Crivello et al. (2016) There is no report on factorial analysis or reli- Exposure to language (BL and ML). TE and BL children showed advantages in inhibitory ability. expressive vocabulary control. TE predicts better performance in conflict tasks but not in delay tasks. The authors confirm the relationship between EFs and early bilingual- ism. Marcovitch et al. (2016) There is no report on the factorial analysis. Cron- Attention (short and long lookers). Percentage of Attention is related to emerging object permanence bach’s interrater reliability in looking A-not-B time attending to the puppet and the peak fixa- and cognitive flexibility at 5 months old. Children task is .99. tion time of mothers with less education and shorter peak fixation time have higher object permanence and cognitive flexibility skills. Pauen and Bechtel-Kuehne (2016) There is no report on the factorial analysis. Based Use of tools From 18 to 24 months old, means-ends involving on previous studies that refer to each task as a tools are learned by observing others. Training component. Interrater agreement with performance, focusing on tool-relevant infor- ICC = .96. mation, and the ability to profit from positive feedback improve with age. Set switching and In were associated with better spontaneous transfer performance and less fixation on perceptually salient but functionally irrelevant tool features. WM helps to update information, allowing a faster adaptation of tool choices based on the feedback information. Garon et al. (2018) Explained by Garon et al. (2014). All tasks: inter- Cognitive ability Lower scores in 3 basic EFs in children with ASD, nal reliability for tasks ranging from .71 to .93 showing the moderation of mental and chrono- logical age. It is important to measure simple EFs in very young children with ASD. Treat et al. (2019) There is no report on factorial analysis or reli- Parental traumatic experiences and harsh parental A higher level of the parent’s adverse childhood ability. attitudes experiences predicts a lower WM performance in their children. Harsh parenting attitudes predict lower inhibitory control in children and are nega- tively associated with lower CF. 13 Advances in Neurodevelopmental Disorders includes the interaction of the examiner. This consists of the WM working memory, In inhibition, CF cognitive flexibility, CF conflict tasks, CS composite score (including WM, In, CF), IC impulsive control, TE translation equivalents, ICC intraclass cor- negatively associated with inhibition at 10 months it has adequate statistical validation processes and children of ages ranging from 9 to 30 months old, old (above first levels of attention and individual children standing up and pretending to hold a flag in their The EEFQ provides a reliable measure for EFs in Screen exposure at 4 months old appears to be hands for 75 s. Every 5 s, the examiner attempts to distract the child by recording any body movement of the child (e.g., eye opening or vocalization). The score is recorded in inter- is sensitive to age-related changes. vals. Two points are scored per error-free interval: one point if one error is made and zero if two or more errors are made. differences in temperament). The tasks shape Stroop task, children’s continuous per- formance task (C-CPT), and tricky-box task (Crivello et al., 2016; Espy et al., 2004) had a more complex goal, requir- ing the child to inhibit a distractor stimulus to achieve an instruction. The shape Stroop task consists of two phases: Main results In the first phase (identification phase), the examiner intro- duces to the child three pictures with large fruits (i.e., apple, banana, and orange) and three pictures with the same fruits but smaller and placed below the large ones. Afterward, the small fruits are removed, and the children are asked to point to each fruit by telling the name and size, and feedback is Attention focusing and attention shifting given when they do it correctly. In the second phase (Stroop phase), the small pictures are placed below the large pictures but without matching them, and again, the child is asked to point to each fruit by telling the name and size; however, no feedback is given in this phase. The number of attempts Other variables included Screen exposure time to identify the small fruits in this Stroop phase is recorded. Regarding the C-CPT task, this is a computerized task in which the child is presented with images and sounds of sev- eral animals for 3 min. The sound of the animal should not match the image. After a familiarization phase, the child is instructed to press the button only when the animal (e.g., sheep) is visually presented, regardless of the sound it interest but the EFA scores showed vulnerability to measurement error. Cronbach’s alpha for CEF regulation was included since it is of theoretical and regulation was in the range of .751 to .876. Two factors are reported: WM and CF. No latent makes. Commission errors are scored, as they better measure factor was estimated for inhibition. High and and included the In, CF, and WM tasks. The tion” (CEF) explained 36% of the variance poor modulation of response inhibition. For the tricky-box A factor called “cognitive executive func- perfect interrater reliability in the tasks. task, two identical but different-colored boxes are used. Each box has two red levers at the top and two transparent doors at the bottom. Behind the doors, there is a hidden toy. In one Internal structure and reliability of the boxes, each lever lifts the door just below it. In the other box (conflicting), each lever lifted the opposite door. The above three tasks respond to a more complex inhibitory control. Cognitive Flexibility Tasks A commonly used task for assessing EFs at early ages is the A-not-B task, which is often used to assess the rudi- mentary form of CF. The search pattern necessary for this task develops from 5 months old in its simplest form and is Hendry and Holmboe (2021) more complex at 7 or 8 months old. A study with a sample of 10-month-old children allows differentiation of A-not- McHarg et al. (2020) Table 3  (continued) B responses in reaching and looking modalities (Johans- son et al., 2014). The reaching response refers to when the child’s first response is to touch one of the presented screens. Authors relation The looking response refers to the first look toward one of the screens for at least three frames (> 100 ms). This study 13 Advances in Neurodevelopmental Disorders supports that the looking modality in the A-not-B task is less that WM updating-in-mind exhibits a more gradual develop- cognitively demanding than the reaching modality. In the ment than inhibition and CF. same context, Marcovitch et al. (2016) applied the A-not-B The Early Executive Function Questionnaire (EEFQ) task to 5-month-old children; however, a limitation emerged aimed to assess EF in children aged between 9 and 30 as the A-not-B task could be inadequate for this age because months old (Hendry & Holmboe, 2021). The exploratory the rule to stop the activity might be too strict. Hence, it factor analysis (EFA) and the confirmatory factor analysis might be more appropriate to measure object permanence (CFA) identified one factor for cognitive EFs with adequate and not CF at the age of 5 months old. The authors con- psychometric properties which included the three basic EFs cluded that more research should be carried out considering (WM, In, and CF). They called the factor “cognitive execu- recent studies on EFs for this age group and their relation- tive function” (CEF). Additionally, Cronbach’s alpha for ship with other skills, such as language. CEF was .751. Authors studied regulation as another factor In addition to the A-not-B task, CF was assessed with because it was theoretically important but did not obtain tasks that require classification, such as the categoriza- sufficient statistical support. tion task, the reverse categorization task, the DCCS scale, It is important to note that none of the selected studies and shape and color sort (Pauen & Bechtel-Kuehne, 2016; in this contribution used BRIEF-P or Stanford Binet-5 to Treat et al., 2019). These tasks have multiple procedures, assess EFs; therefore, they were not described in this section. depending on the child’s age. The simplest is when the child However, the usefulness of both tests to assess EFs from 24 must sort toys according to some feature (e.g., size) into the months of life should be emphasized. appropriate pot. A more complex version requires children to sort toys in the opposite pot. Sorting can also be done by The Unidimensional Model of EFs asking the child to select and sort specific cards (e.g., stars and trucks) among many different cards. The most compli- The factor structure most reported in the review responds to cated is to sort items by color and shape. The simplest ver- the unidimensional model, in which WM, inhibition, and CF sion of this task was applied to children up to 17 months old, constitute the common components of EFs. This common and the most complex was up to 24 months old. However, score has been referred to as conflict EFs (Bernier et al., as in the previous EF measures, performance on these tasks 2012; Matte-Gagné & Bernier, 2011), composite score (Cue- improves with age. vas & Bell, 2014; Hostinar et al., 2012), or cognitive execu- Other tasks such as ball run task, flap book, spatial rever- tive function (Hendry & Holmboe, 2021). Table 3 shows sal, and spatial reversal with irrelevant color cues were the results related to internal structure and reliability (when applied to assess CF. However, the most relevant are those reported in the study), as well as other variables analyzed mentioned above. and the main findings of each study. Garon et al. (2014) demonstrated that a common EF fac- Battery and Questionnaire to Assess EFs tor contains the three basic EFs, which are separated into two factors characterized by simple and complex tasks. Garon et al. (2014) developed a battery, which assesses WM, These authors suggest that EFs before 36 months old inhibition, and CF in pre-schoolers. They applied the battery may have different developmental trajectories that can be to a sample of 261 children ranging from 18 to 67 months assessed with simple and complex tasks (Garon et al., 2014, old. Authors showed that all EF measures were positively 2018). Although, some studies showed 3 latent dimensions, correlated with chronological and mental age. Moreover, the separating WM, inhibition, and CF (McHarg et al., 2020; test was shown to be sensitive to age differences between 18 Pozzetti et al., 2014), the unidimensional model was more and 67 months old. Additionally, it was observed that devel- reported. Moreover, the unidimensional model has been opmental evolution was not the same among the three basic obtained with an adequate sample size (200 or more par- EFs. The factor structure of the three basic EFs resulted in ticipants) necessary for any AFE and CFA. Regarding reli- two factors for each one; for WM, the factors were holding- ability, many studies do not report it, and those that report in-mind and updating-in-mind. Regarding CF, the factors internal consistency reliability showed a Cronbach’s alpha were task set and task switch. Finally, for inhibition, the fac- above .70, whereas others only indicate that it was low or tors were simple and complex inhibition. Reliability ranged limited. Nonetheless, interrater reliability was reported in from .70 to .93 in all tasks. The authors concluded that the five studies showing adequate values from .86 to .99. In sum- early development of simple EFs (e.g., holding-in-mind, mary, the unidimensional model appears to be consistent in task set, and simple inhibition) is faster during the preschool studies of EFs before 36 months old. However, it should be stage and decelerates with age. Complex inhibition and CF considered that the factor structure and psychometric fea- task shift showed slight acceleration as age increases, while tures should be reported in the studies to reinforce the sup- WM holding-in-mind shows deceleration. Therefore it seems port for this model. 13 Advances in Neurodevelopmental Disorders Variables Related to EF Measurement trials in which the child selects a tool for the examiner to insert into the tube and provides feedback to the child (learn- One of the challenges of measuring EFs is the difficulty of ing about the tool based on feedback). Finally, there is a separating the measurement from other processes involved transfer phase in which the examiner replaces the training in EFs. In this review, attention, object permanence, and tools with new sticks and provides instruction to the child language were associated with EF measures. allowing 7 to 12 trials (transfer of tool knowledge to new First, there is a relationship between EFs and attention. situations). Their study found that children at 18, 20, 22, and Cuevas and Bell (2014) demonstrated that the type of atten- 24 months old chose the correct tool after seeing another tion used at 5 months old is potentially associated with EFs person apply it, increasing substantially the performance as at older ages. The authors classified the participants accord- the age group was older, especially between 20 (45%) and ing to attention style in short lookers (SL) and long lookers 22 months old (63%). Children who scored higher on WM (LL) as reported by Colombo et al. (1991). They found that made fewer perceptual errors after feedback; for example, SL process information faster than LL since they encode those who waited longer before starting to eat the cookie in global features, while LL tend to encode more localized the inhibition task chose the wrong tool less frequently than features. Subsequently, they assessed the EFs of the same those who did not wait; also, in CF, it was observed that participants at 24, 36, and 48 months old, showing that SL switching skills helped to shift children’s perspective from scored higher on EFs throughout early childhood compared paying attention on perceptually salient information toward to LL, even when controlling verbal intelligence in the com- paying attention on functionally relevant information. The parison. Likewise, Marcovitch et al. (2016) also included results revealed that EFs are likely to impact the knowledge attention for 5-month-old children in two measures: (a) the transfer of tools in young children. percentage of looking time that was spent focusing on a pup- Finally, language is an important variable related to EF pet over the entire task and (b) the length of the longest look development. Language skills operate as a support tool to that was recorded. The most relevant of their results were inhibit impulsive responses, improve self-control, and have as follows: (a) Attention is a predictor of the location of an adequate social interaction (Matte-Gagné & Bernier, 2011). object when it is hidden from the child’s view. (b) Maternal Several of the reviewed studies included a measure of verbal education is associated with the child’s maximum focus time ability, language, or vocabulary to control for the influence on the object; for example, children of mothers who did not on EFs (Bernier et al., 2012; Cuevas & Bell, 2014). The complete university or technical school present lower focus instructions of the EF tasks should also be adapted to the time. (c) Babies who hold attention for longer periods find level of verbal development of children at this age. the correct hiding place more often because the longer time of holding attention allows them to encode a greater amount Biological and Environmental Factors Related to EF of information, including the location of the hidden object. Development And, (d) at 7 months old, the child can relate the location of an object to its features; however, separate coding of features The review shows that basic EFs before 36 months old are and location occurs at earlier ages. influenced by variables such as prematurity, ASD, parent- Second, locating hidden objects is tied to the develop- ing, attachment, adverse early life experiences, bilingualism, ment of object permanence; however, when multiple loca- and screen exposure. The findings about these variables are tions are used to hide objects, the EFs are practiced (Marco- described below. vitch et al., 2016). This shows that difficulties in developing Premature birth is a relevant risk factor associated with object permanence reflect deficiencies in inhibition and EF difficulties and neurodevelopmental disorders. Pozzetti WM. For example, Pauen and Bechtel-Kuehne (2016) stud- et al. (2014) studied this condition in children without sig- ied how tool use is associated with the development of EFs. nificant brain damage and assessed the three basic EFs at They used Bechtel et al.’s (2013) tool selection task, which 24 months old. The authors compared 72 premature infants requires a transparent box with a tube and a ball (reward), and 73 as controls, finding that premature infants without as well as three sticks (tool) of different appearances and significant brain damage have adequate cognitive develop- lengths. The sticks must be inserted through the tube, but ment with difficulties only in CF which could be a precur- only the longest one can reach the ball to drop it down a sor to deficits in young children. These difficulties could ramp and for the child to get it. First of all, the examiner become more evident as they reach school age, when they inserts each tool into the apparatus in three consecutive are subjected to more complex tasks and the demands of the attempts, from the shortest to the longest stick, showing the environment increase, resulting in academic and behavioral child that only the longest stick pushed the ball out of the problems. Espy et al. (2004) considered a single sample that tube (learning about the tool by observing others). The task included typically developing children and premature chil- continues with a training phase, which consists of several dren at 28 weeks gestation or more but without significant 13 Advances in Neurodevelopmental Disorders brain damage. They made this decision to increase the vari- strategies learned during emotionally evocative child-caregiver ability of performance by including children more likely to interactions and (2) more advanced psychobiological regula- experience later mathematical difficulties. In their study, tion, which supports the development of neural systems that they determined that WM and inhibition could predict math underlie children’s ability to regulate thoughts and behaviors skills later in development. However, the authors consid- (Bernier et al., 2012). This is because care is presented in a ered the limitation that the sample included children born harmonious environment, reducing negative emotional stimu- preterm, as their findings might have differed with a more lation, which can affect physiological processes such as para- homogeneous sample. sympathetic responses and cortisol reactivity. Parents’ early Among the studies reviewed, only one included a sample traumatic experiences could also impact the quality of care of children with ASD in the age group of interest. Garon and as a consequence influence child EFs, specifically on lower et al. (2018) applied their EF battery to 34 children with performance in WM and inhibitory control scores due to harsh ASD and compared them with 255 children with typical parenting attitudes (Treat et al., 2019). development. Their results showed deficits in children with Likewise, adverse experiences in a child’s first year of life ASD in all the basic EFs assessed which were more evident can negatively influence child development. Hostinar et al. when the tasks were appropriate for their level of develop- (2012) showed that post-adopted children with early life ment. These authors observed significant deficits in cogni- deprivation have lower performance in EFs, even after con- tive flexibility and inhibition rather than in WM, regardless trolling for intelligence quotient (IQ) as a covariate. Specifi- of age. This implies that these ability deficits are not only cally, the amount of time children spend in their biological observed in children with ASD but are also evident at early family before being placed for adoption and the physical and ages in the preschool period. The two abilities that most dis- social quality of the orphanage environment (reported by the tinguished the groups were inhibition (simple and complex parents and an expert from the adoption agency) influence phase) and CF (simple and complex phase). In WM, the sim- the EF composite (WM, inhibition, and CF). These authors ple phase score had a slightly higher load than the complex showed that even at the age of 2.5 years old, difficulties in phase, indicating that these deficits may be associated with EFs due to exposure to these experiences can manifest. developmental delays and not specifically with ASD symp- Proficiency in two languages may be a protective factor tomatology. Although deficits in inhibition were observed, for EFs. Likewise, bilingualism may predict the develop- CF was the one that best marked the severity of the symp- ment of EFs at later ages. Translation equivalents (TEs) toms in children with ASD. The study concluded that these are lexical representations of the same concept in differ- measures could be candidates for endophenotypes, which ent languages, which predict cognitive benefits in bilingual would be an important line of research to further understand children. Increased TEs predicted stronger EF mechanisms, neurodevelopmental disorders. particularly in conflict tasks. In monolinguals, there was no The parent-child interaction and the quality of the environ- relationship between increased vocabulary and conflict EF ment at an early age also influence EFs. A favorable environ- tasks, supporting that bilingualism produces this cognitive ment can have a positive impact, while an unfavorable one can advantage. Bilinguals also showed superior selective atten- have a negative structural and functional influence (Bernier tion and inhibitory control, because they must focus their et al., 2010; Bernier et al., 2012). Maternal care, specifically attention on one language while ignoring the other (Crivello mind-mindedness, sensitivity, and autonomy support appear et al., 2016). to influence conflict EF tasks, operating as a central mecha- Finally, exposure to screens is associated with lower nism in both cognitive and behavioral psychophysiological scores in inhibition (considering the response time to the regulation, being maternal autonomy support the most impor- prohibition task with a 5-s delay); this difference is not tant predictive factor of EFs at all ages (Bernier et al., 2010). observed in WM or CF, suggesting a longitudinal associa- Individual differences and aspects related to the family (e.g., tion between exposure to screens and inhibition only. These stressful parenting or lack of opportunities) or the child’s ver- results were observed even with other risk variables such as bal ability can affect the development of EFs (Matte-Gagné parental mental health problems or relationship difficulties & Bernier, 2011). The longitudinal study of Bernier et al. (McHarg et al., 2020). Table 4 shows the variables that influ- (2012) looked at possible links between the quality of early ence specific EFs (WM, inhibition, CF, or composite score). care environment and EFs later in life and demonstrated that parenting and secure attachment were linked to conflict tasks at the age of three, even when taking into account socioeco- Discussion nomic status, child’s language, and previous performance on conflict tasks. Authors argued that the association between This review highlights the advances and challenges in the conflicting EFs and secure attachment is mainly attributable study of EFs before 36 months old. The study of EFs at early to two mechanisms: (1) the independent use of regulation ages has great research potential; however, it has only been 13 Advances in Neurodevelopmental Disorders Table 4  Variables influencing Variables influencing EFs Basic EFs basic EFs CS/CT WM In CF Preterm birth ✓ ASD ✓ ✓ The severity of symptoms in ASD ✓ Maternal autonomy support ✓ Parent’s early traumatic experiences ✓ Secure attachment ✓ Parenting (moderated by language) ✓ The amount of time children spend in their biological family ✓ before being placed for adoption The physical and social quality of the orphanage environment ✓ Bilingualism ✓ The number of translation equivalents ✓ Exposure to screens ✓ Object permanence development ✓ ✓ Short lookers (fast and efficient information processing) ✓ WM working memory, In inhibition, CF cognitive flexibility, CF conflict tasks, CS composite score (including WM, In, CF) understood in greater depth in recent decades. Nonetheless, et al., 2014). Another challenge for correct assessment is there is still much to be known about its development in the to understand which of these basic EFs develops first and first years of life due to the challenges of observing, meas- what influence they have on each other, as well as their uring, and differentiating it from other constructs (García- impact on different populations. For example, Garon et al. Molina et al., 2009; Tirapu-Ustárroz et al., 2002). (2018) reported a greater impact on CF in their ASD sample. The following points are discussed in this section: (1) Therefore, it has been found essential to develop sensitive the existing measures to assess the three basic EFs, (2) the and validated measurements of EF in longitudinal studies evidence in favor of the unidimensional model before 36 (Diamond, 2015). In this review, the battery of Garon et al. months old, (3) the relevant findings relevant to understand- (2014) showed sensitivity from 1.5 to 5 years old, and the ing the complexity of measuring these three EFs at early questionnaire of Hendry and Holmboe (2021) showed sen- ages, and (4) the benefits for the study of neurodevelop- sitivity from 9 to 30 months old. As previously mentioned, mental disorders at early ages. In each of the above points, studies with samples of children younger than 36 months the advances and challenges extracted from the review are old are complicated to carry out, so it is essential to work presented. on increasing the number of these younger participants. For Regarding the existing measures and scales, 66 tasks were instance, two studies in our review, that aim to describe psy- identified that allowed measuring EFs before 36 months old. chometric properties, have 261 (Garon et al., 2014) and 486 There are current efforts by researchers to adapt the tasks to participants (Hendry & Holmboe, 2021). The other studies simpler versions for application to children at younger ages were not intended to show psychometric properties, some of (Pozzetti et al., 2014). Nevertheless, more complex tasks them had large samples (Cuevas & Bell, 2014; Garon et al., have been successfully applied at older ages. The tasks for 2018; Marcovitch et al., 2016; McHarg et al., 2020; Pauen each EF have common goals, such as finding an object, con- & Bechtel-Kuehne, 2016; Pozzetti et al., 2014), and the rest trolling behavior, or being able to switch from one task to had samples of less than 100 participants (see Table 2). On a another (WM, inhibition, and CF respectively). Describing sample of more than two thousand 2-year-old children, a bat- and applying the simple and complex tasks would allow for tery divided the EFs into hot and cool, meeting psychomet- longitudinal studies to explain the development process of ric quality, and predictive and convergent validity (Mulder these basic EFs from very early ages. The diversity of tasks et al., 2014). The adequate platforms and data collection described generates the challenge of carrying out strict vali- procedures can allow for bigger samples to corroborate the dation processes; however, they are not always reported in structure of EF measurements. The review identified three the publications. The process of test standardization is nec- tests that showed statistical evidence on the assessment of essary to obtain more reliable results. However, EF tasks EFs at the ages relevant for our study (Garon et al., 2014; are reliable and can be applied to large samples (Mulder Gioia et al., 2016; Hendry & Holmboe, 2021), one was a 13 Advances in Neurodevelopmental Disorders battery of tasks, and the rest are questionnaires for caregiv- shown to mediate between inhibitory control and impulsive ers. However, some EF tasks require an individual applica- responses, so it should be taken into account in future studies tion and specific devices, hindering the accessibility for large (Matte-Gagné & Bernier, 2011). Child attention has been samples (Johansson et al., 2014; Pozzetti et al., 2014). shown to have a significant relationship and influence with Concerning the second discussion point, there is evidence EFs as early as 5 months old; furthermore, there is evidence of the use of specific tasks to measure the three basic EFs that it is related to EF performance at later ages as well (Cue- before 36 months old which applied factorial analysis to vas & Bell, 2014). This implies that attention should always corroborate the internal structure and correlations between be considered in the measurement of EFs, not as part of the observed variables and thus reduce variables to factors (see construct, but as an effective influencing variable. Likewise, Table 3). Most of the reviewed studies showed common the development of the child’s attention must be determined scores for WM, CF, and inhibition, which were referred to in each stage of life with greater specification. Attention, as conflict tasks or composite scores (Bernier et al., 2012; object permanence, and tool use, while not part of the same Matte-Gagné & Bernier, 2011). Though, other research still construct, are precursors to the development of EFs and can divides the three basic EFs (McHarg et al., 2020; Pozzetti be observed at very early ages (Decker et al., 2016; Pauen & et al., 2014). This discrepancy reflects the challenges in Bechtel-Kuehne, 2016). Additionally, temperament, similar measuring EFs. The unidimensional model seems to better to EFs, predicts inhibition outcomes. However, the challenge explain EFs at these ages (Karr et al., 2018; Rose, 2022). is to understand how to differentiate the measurement of Several studies reported a factor structure to divide EFs into these variables from a multi-theoretical and multi-method hot and cool (Goldstein & Naglieri, 2014; Zelazo, 2020). approach (Aguilera Lázaro & Ostrosky-Shejet, 2013; Rocha The challenge here is to continue analyzing the factorial et al., 2019). It should be considered that to measure EFs, it model that is reported in literature, especially in studies with is necessary to maintain the child’s interest, avoid fatigue, large samples. Challenges also include well-documented val- provide situations that require reasoning and integration of idation processes, and assessments of the evolution over time various sources of information, and consider the procedure, (Hunter & Sparrow, 2012). Again, researchers are encour- errors, and context (Hoskyn et al., 2017). aged to report all EFA data as well as internal, external, and Returning to environmental influences, positive parenting interrater reliability. favors verbal skills that help develop inhibitory control in The third discussion point is the complexity of the devel- the child, a basic skill of executive functioning at an early opment of EFs that influences how researchers measure age. In this way, it has been shown that competent parenting them. Understanding the influence of environmental vari- influences infant development since the caregiver is involved ables, in addition to the statistical requirements mentioned in the child’s self-regulatory skills (psychophysiological, earlier, can provide insight into whether the tasks truly assess cognitive, and behavioral) (Matte-Gagné & Bernier, 2011). what they are intended to assess. Variables such as socio- The genetic influence of these factors and the order of pro- economic level, maternal education, history of neurode- tective importance have yet to be determined. Nonetheless, velopmental disorders in the family, limited opportunities, these findings have shown the importance of including par- conditions of adversity, bilingualism, child temperament, IQ, ents in early intervention models. Taking into account that language, and early trauma can influence the development family involvement is crucial for the development of EFs, of EFs (Motsan et al., 2021; Waters et al., 2021). Related to questionnaires directed to parents/caregivers may provide parenting, factors such as parent-child interaction, the qual- reliable evidence of children’s executive functioning at these ity of care, the environment in which a child is educated, early ages (Gioia et al., 2016). secure attachment, autonomy support, mind-mindedness, The study conducted in institutionalized children (Hosti- adversities in life, and stress can also influence children’s nar et al., 2012) highlights the need to address aspects that EFs (Brown et al., 2022; Werchan et al., 2022). Therefore, can prevent and reduce the impact of adversity on cognitive it is relevant to control these variables in early EF research. development in the short and long term. Extensive practice One challenge is to separate developmental processes that of a second language appears to be effective in EF devel- are highly influential in children’s performance, such as lan- opment (Crivello et al., 2016). Even minimal exposure to guage, attention, and temperament. EFs are influenced by screens appears to decrease executive functioning skills very knowledge acquired during development, beliefs, norms, and early in life (McHarg et al., 2020). Parents should be advised values, which must be taken into account in understanding to reduce screen use at an early age, especially when screen children’s task performance to assess executive functioning interaction is not possible. (Doebel, 2020). The level of language developed by the child In recent years, substantial advances in the study of EFs influences the comprehension of the given task. Hence, the have been made due to neuroimaging technologies (Fiske & less verbal instruction required, the better we can control Holmboe, 2019). The main difficulties include the complex- the child’s actual performance. Besides, language has been ity of developmental research, such as intergenerational and 13 Advances in Neurodevelopmental Disorders longitudinal studies with large samples, although this could other biological, environmental, and social variables that help to better understand EF behavior (Deater-Deckard, may influence the measurement of EFs before 36 months 2014). There may be an endophenotype related to EFs, spe- old. Measuring these functions at early ages can allow early cifically in the study of ASD (Demetriou et al., 2019; Garon identification and intervention when warning signs for neu- et al., 2018). Nevertheless, hormonal influences have been rodevelopmental disorders appear, preventing and reducing described in EF development such as cortisol in psycho- the impact on quality of life and improving the adaptation biological regulation (DePasquale et al., 2021; Feola et al., of the child and family. Some of the study’s limitations are 2020). These endogenous factors have a strong influence and related to the diversity of topics that had to be analyzed sepa- must be considered separately, but how they interact with rately and the lack of studies using the early age range con- environmental variables should be considered. There is still sidered in our review. Longitudinal studies with large sam- much to be done to understand in greater detail the impact of ples should also be conducted to achieve ecological validity. the environment on EFs, and new theories, innovative meas- The inclusion of measurement of the three basic EFs in their urements, and novel interventions should be developed since simple and complex versions will help to understand how there are many factors that can affect them (Doebel, 2020). they evolve. Although the unidimensional model appears to Finally, for our fourth discussion point, it remains to be explain EFs before 36 months old, it is important to compare determined with greater precision how performance on EF studies reporting the bidimensional model of hot and cool tasks before 36 months old is related to neurodevelopmental EFs. Research with children at risk for neurodevelopmental disorders. Until now, ASD assessment has shown signifi- disorders (even if undiagnosed) will provide a better under- cant results because its identification has been achieved at standing of behavior before 36 months old. younger ages, but the current differentiation of signs and Acknowledgements The collaboration of the División Académica symptoms between boys and girls leaves much to be discov- Multidisciplinaria de Comalcalco, Universidad Juárez Autónoma ered regarding the development of EFs in early ages (Garon de Tabasco in the development of this article is also gratefully et al., 2018; Tomaszewski et al., 2020). Future research acknowledged. should focus on understanding the relationship between Author Contribution VER: designed and executed the study and early EF difficulties with symptoms of risk for neurodevel- assisted with the data analyses and paper writing. PA: collaborated opmental disorders and, if possible, differentiate them from with the design and writing of the study and assisted with the data other impairments. The most plausible one is to analyze the analyses. CT: collaborated with the design and writing of the study. signs and symptoms of risk for neurodevelopmental disor- ED: collaborated with the design and writing of the study. MJ: col- laborated with the design and writing of the study. All authors approved ders in children younger than 36 months old and compare the final version of the manuscript for submission. them with EF tasks at early ages. With all this information, we not only provide treatment Funding Open Access Funding provided by Universitat Autonoma de alternatives or intervention programs but also recommenda- Barcelona. This work was supported by the Mexican National Council of Humanities, Science, and Technology (CONAHCYT) through the tions for the study of the measurement of EFs at early ages. funding of a Ph.D. studentship to Valeria Escobar-Ruiz at Universitat Intervention should consider changes in different contexts Autònoma de Barcelona. ranging from the inclusion of physiological measures, the promotion of resilience, the reduction of screen use, and Declarations the implementation of strategies to reduce adversity or to Competing Interests The authors declare no competing interests. create healthy parent-child relationships. More longitudinal studies, with large samples and involving gene-environment Open Access This article is licensed under a Creative Commons Attri- interaction, are required to obtain firm conclusions about bution 4.0 International License, which permits use, sharing, adapta- their influence on EFs (Deater-Deckard, 2014; Inguaggiato tion, distribution and reproduction in any medium or format, as long et al., 2017). as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are Limitations and Future Research included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in The interest of researchers in EF development before 36 the article's Creative Commons licence and your intended use is not months old is increasing; hence, new studies must contem- permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a plate the earliest stages of EF development. Psychometric copy of this licence, visit http://​creat​iveco​mmons.​org/​licen​ses/​by/4.​0/. research on EF tasks at these ages can allow for a clearer definition of the construct, to have valid measures that explain the evolution of basic EFs. The development of EFs is complex and multifactorial, so future research should con- trol factors such as language, attention, temperament, and 13 Advances in Neurodevelopmental Disorders References Cuevas, K., & Bell, M. A. (2014). Infant attention and early childhood executive function. Child Development, 85(2), 397–404. https://​ doi.​org/​10.​1111/​cdev.​12126 Aguilera Lázaro, E. C., & Ostrosky-Shejet, F. (2013). Componentes Deák, G. O. (2004). The development of cognitive flexibility and del temperamento y su relación con funciones ejecutivas en tar- language abilities. Advances in Child Development and Behav- eas de inhibición y toma de decisiones en niños [Temperament ior, 31(C), 271–327. https://​doi.​org/​10.​1016/​S0065-​2407(03)​ components and their relationship with the executive functions in 31007-9 inhibition tasks and decision making in children]. Revista Neu- Deater-Deckard, K. (2014). Family matters: Intergenerational and inter- ropsicología, Neuropsiquiatría y Neurociencias, 13(1), 15–26 personal processes of executive function and attentive behavior. http://​neuro​cienc​ias.​udea.​edu.​co/​revis​t a/​PDF/​REVNE​URO_​ Current Directions in Psychological Science, 23(3), 230–236. vol13_​num1_5.​pdf https://​doi.​org/​10.​1177/​09637​21414​531597 Ameis, S. H., Lerch, J. P., Taylor, M. J., Lee, W., Viviano, J. D., Pipi- Decker, S. L., Ezrine, G. A., & Ferraracci, J. (2016). Latent dimen- tone, J., Nazeri, A., Croarkin, P. E., Voineskos, A. N., Lai, M. sions of executive Functions in early childhood. Journal of Pedi- C., Crosbie, J., Brian, J., Soreni, N., Schachar, R., Szatmari, P., atric Neuropsychology, 2(3–4), 89–98. https://​doi.​org/​10.​1007/​ Arnold, P. D., & Anagnostou, E. (2016). A diffusion tensor imag- s40817-​016-​0013-0 ing studyin children with ADHD, autism spectrum disorder, OCD, Demetriou, E. A., DeMayo, M. M., & Guastella, A. J. (2019). Execu- and matched controls: Distinct and non-distinct white matter dis- tive function in autism spectrum disorder: History, theoretical ruption and dimensional brain-behavior relationships. American models, empirical findings, and potential as an endophenotype. Journal of Psychiatry, 173(12), 1213–1222. https://​doi.​org/​10.​ Frontiers in Psychiatry, 10, 1–17. https://​doi.​org/​10.​3389/​fpsyt.​ 1176/​appi.​ajp.​2016.​15111​435 2019.​00753 Arksey, H., & O’Malley, L. (2005). Scoping studies: Towards a meth- DePasquale, C. E., Tyrell, F. A., Kalstabakken, A. W., Labella, M. H., odological framework. International Journal of Social Research Thibodeau, E. L., Masten, A. S., & Barnes, A. J. (2021). Life- Methodology: Theory and Practice, 8(1), 19–32. https://​doi.​org/​ time stressors, hair cortisol, and executive function: Age-related 10.​1080/​13645​57032​00011​9616 associations in childhood. Developmental Psychobiology, 63(5), Bechtel, S., Jeschonek, S., & Pauen, S. (2013). How 24-month-olds 1043–1052. https://​doi.​org/​10.​1002/​dev.​22076 form and transfer knowledge about tools : The role of percep- Diamond, A. (2002). Normal development of prefrontal cortex from tual , functional , causal , and feedback information. Journal of birth to young adulthood: Cognitive functions, anatomy, and bio- Experimental Child Psychology, 115(1), 163–179. https://d​ oi.o​ rg/​ chemistry. in D. T. Seuss & R. T. Knight (Eds.), Principles of 10.​1016/j.​jecp.​2012.​12.​004 frontal lobe function (pp. 466–503). Oxford University Press. Bell, M. A. (2012). A psychobiological perspective on working mem- Diamond, A. (2015). Why improving and assessing executive functions ory performance at 8 months of age. Child Development, 83(1), early in life is critical. Executive Function in Preschool-Age Chil- 251–265. https://​doi.​org/​10.​1111/j.​1467-​8624.​2011.​01684.x dren: Integrating Measurement, Neurodevelopment, and Transla- Bernier, A., Carlson, S. M., Deschênes, M., & Matte-Gagné, C. (2012). tional Research., 11–43. https://​doi.​org/​10.​1037/​14797-​002 Social factors in the development of early executive functioning: Díaz, M. C., & Guevara, P. (2016). Desarrollo de las Funciones Ejecu- A closer look at the caregiving environment. Developmental Sci- tivas durante la primera infancia y su afectación ante un Trau- ence, 15(1), 12–24. https://​doi.​org/​10.​1111/j.​1467-​7687.​2011.​ matismo Craneoencefálico [Development of Executive Functions 01093.x during first childhood and Traumatic Brain Injury consequences]. Bernier, A., Carlson, S. M., & Whipple, N. (2010). From external regu- Revista Chilena de Neuropsicología, 11(2), 40–44. https://d​ oi.o​ rg/​ lation to self-regulation: Early parenting precursors of young chil- 10.​5839/​rcnp.​2016.​11.​02.​07 dren’s executive functioning. Child Development, 81(1), 326–339. Doebel, S. (2020). Rethinking executive function and its development. https://​doi.​org/​10.​1111/j.​1467-​8624.​2009.​01397.x Perspectives on Psychological Science, 15(4), 942–956. https://​ Blair, C., Zelazo, P. D., & Greenberg, M. T. (2005). The measure- doi.​org/​10.​1177/​17456​91620​904771 ment of executive function in early childhood. Developmental Espy, K., McDiarmid, M., Cwik, M., Stalets, M., Hamby, A., & Senn, Neuropsychology, 28(2), 561–571. https://​doi.​org/​10.​1207/​s1532​ T. (2004). The contribution of executive functions to emergent 6942d​n2802_1 mathematic skills in preschool children. Developmental Neuropsy- Blanco Villaseñor, Á., i Riba, S. S., & Escolano Pérez, E. (2010). chology, 26(1), 465–486. Desarrollo ejecutivo temprano y teoría de la Generalizabilidad: Feola, B., Dougherty, L. R., Riggins, T., & Bolger, D. J. (2020). Pre- Bebés Típicos y prematuros [Executive function in early child- frontal cortical thickness mediates the association between cor- hood and generalizability theory: Typical babies and preterm tisol reactivity and executive function in childhood. Neuropsy- babies]. Psicothema, 22(2), 221–226 https://​www.​redal​yc.​org/​ chologia, 148(July), 107636. https://d​ oi.o​ rg/1​ 0.1​ 016/j.n​ europ​ sych​ artic​ulo.​oa?​id=​72712​496008 ologia.​2020.​107636 Brown, A., Yoder, J., & Fushi, K. (2022). Trauma and maternal car- Fiske, A., & Holmboe, K. (2019). Neural substrates of early executive egivers as risks for executive function deficits among youth who function development. Developmental Review, 52(July), 42–62. have sexually harmed. Sexual Abuse: Journal of Research and https://​doi.​org/​10.​1016/j.​dr.​2019.​100866 Treatment, 34(1), 24–51. https://​doi.​org/​10.​1177/​10790​63220​ Gagne, J. R., Barker, K., Chang, C. N., Nwadinobi, O. K., & Kwok, 988289 O. M. (2021). A multi-theoretical and multi-method family study Colombo, J., Mitchell, D., Coldren, J., & Freeseman, L. (1991). Indi- approach to preschool inhibitory control: Links to working mem- vidual differences in infant visual attention: Are short lookers ory, receptive vocabulary, behavioral maladjustment, and parent faster processors or feature processors? Child Development, 62(6), mental health in the context of temperament and executive func- 1247. https://​doi.​org/​10.​2307/​11308​04 tioning perspecti. Frontiers in Psychology, 12. https://​doi.​org/​10.​ Crivello, C., Kuzyk, O., Rodrigues, M., Friend, M., Zesiger, P., & Pou- 3389/​fpsyg.​2021.​703606 lin-Dubois, D. (2016). The effects of bilingual growth on toddlers’ García-Molina, A., Enseñat-Cantallops, A., Tirapu-Ustárroz, J., & executive function. Journal of Experimental Child Psychology, Roig-Rovira, T. (2009). Maduración de la corteza prefrontal y 141, 121–132. https://​doi.​org/​10.​1016/j.​jecp.​2015.​08.​004 desarrollo de las funciones ejecutivas durante los primeros cinco años de vida [Maturation of the prefrontal cortex and develop- ment of the executive functions during the first five years of life]. 13 Advances in Neurodevelopmental Disorders Revista de Neurología, 48(08), 435. https://​doi.​org/​10.​33588/​rn.​ Marcovitch, S., Clearfield, M. W., Swingler, M., Calkins, S. D., & 4808.​20082​65 Bell, M. A. (2016). Attentional predictors of 5-month-olds’ per- Garon, N., Bryson, S. E., & Smith, I. M. (2008). Executive function formance on a looking A-not-B task. Infant and Child Develop- in preschoolers: A review using an integrative framework. Psy- ment, 25(4), 233–246. https://​doi.​org/​10.​1002/​icd.​1931 chological Bulletin, 134(1), 31–60. https://​doi.​org/​10.​1037/​0033-​ Matte-Gagné, C., & Bernier, A. (2011). Prospective relations between 2909.​134.1.​31 maternal autonomy support and child executive functioning: Garon, N., Smith, I. M., & Bryson, S. E. (2014). A novel executive Investigating the mediating role of child language ability. Journal function battery for preschoolers: Sensitivity to age differences. of Experimental Child Psychology, 110(4), 611–625. https://​doi.​ Child Neuropsychology, 20(6), 713–736. https://​doi.​org/​10.​1080/​ org/​10.​1016/j.​jecp.​2011.​06.​006 09297​049.​2013.​857650 McHarg, G., Ribner, A. D., Devine, R. T., & Hughes, C. (2020). Infant Garon, N., Smith, I. M., & Bryson, S. E. (2018). Early executive dys- screen exposure links to toddlers’ inhibition, but not other EF function in ASD: Simple versus complex skills. Autism Research, constructs: A propensity score study. Infancy, 25(2), 205–222. 11(2), 318–330. https://​doi.​org/​10.​1002/​aur.​1893 https://​doi.​org/​10.​1111/​infa.​12325 Gioia, G. A., Espy, K. A., & Isquith, P. K. (2016). BRIEF-P. evaluación Miyake, A., Friedman, N. P., Emerson, M. J., Witzki, A. H., Howerter, conductual de la función ejecutiva-versión Infantil [BRIEF-P. A., & Wager, T. D. (2000). The unity and diversity of executive Behavior Rating Inventory of Executive Function – Preschool functions and their contributions to complex “frontal lobe” tasks: Version] (E. Bausela y T. Luque, adaptadoras). Madrid: TEA A latent variable analysis. Cognitive Psychology, 41(1), 49–100. ediciones. https://​doi.​org/​10.​1006/​cogp.​1999.​0734 Gioia, G. A., Isquith, P. K., Guy, S. C., & Kenworthy, L. (2000). TEST Motsan, S., Yirmiya, K., & Feldman, R. (2021). Chronic early trauma REVIEW Behavior rating inventory of executive function. Child impairs emotion recognition and executive functions in youth; Neuropsychology, 6(3), 235–238. https://​doi.​org/​10.​1076/​chin.6.​ Specifying biobehavioral precursors of risk and resilience. Devel- 3.​235.​3152 opment and Psychopathology, 1–14. https://​doi.​org/​10.​1017/​ Goldstein, S., & Naglieri, J. A. (2014). Handbook of executive func- S0954​57942​10000​67 tioning. Handbook of executive functioning, 1–567. https://​doi.​ Mulder, H., Hoofs, H., Verhagen, J., van der Veen, I., & Leseman, P. P. org/​10.​1007/​978-1-​4614-​8106-5 M. (2014). Psychometric properties and convergent and predictive Hendry, A., & Holmboe, K. (2021). Development and validation of the validity of an executive function test battery for two-year-olds. Early Executive Functions Questionnaire: A carer-administered Frontiers in Psychology, 5(JUL). https://​doi.​org/​10.​3389/​fpsyg.​ measure of executive functions suitable for 9- to 30-month-olds. 2014.​00733 Infancy, 932–961. https://​doi.​org/​10.​1111/​infa.​12431 Pauen, S., & Bechtel-Kuehne, S. (2016). How toddlers acquire and Hoskyn, M., Iarocci, G., & Young, A. R. (2017). Executive functions in transfer tool knowledge: Developmental changes and the role children’s everyday lives: A handbook for professionals in applied of executive functions. Child Development, 87(4), 1233–1249. psychology. Oxford University Press. https://​doi.​org/​10.​1111/​cdev.​12532 Hostinar, C. E., Stellern, S. A., Schaefer, C., Carlson, S. M., & Gunnar, Piaget, J. (1954). The construction of reality in the child (Vol. xiii). M. R. (2012). Associations between early life adversity and execu- Basic Books. tive function in children adopted internationally from orphanages. Pozzetti, T., Ometto, A., Gangi, S., Picciolini, O., Presezzi, G., Gardon, Proceedings of the National Academy of Sciences of the United L., Pisoni, S., Mosca, F., & Marzocchi, G. M. (2014). Emerging States of America, 109(SUPPL.2), 17208–17212. https://​doi.​org/​ executive skills in very preterm children at 2 years corrected age: 10.​1073/​pnas.​11212​46109 A composite assessment. Child Neuropsychology, 20(2), 145–161. Hughes, C., & Devine, R. T. (2019). For better or for worse? Positive https://​doi.​org/​10.​1080/​09297​049.​2012.​762759 and negative parental influences on young children’s executive Rocha, M. S., Yaruss, J. S., & Rato, J. R. (2019). Temperament, execu- function. Child Development. https://​doi.​org/​10.​1111/​cdev.​12915 tive functioning, and anxiety in school-age children who stutter. Hughes, C., & Ensor, R. (2005). Executive function and theory of mind Frontiers in Psychology, 10, 1–14. https://​doi.​org/​10.​3389/​fpsyg.​ in 2 year olds: A family affair? Developmental Neuropsychology, 2019.​02244 28(2), 645–668. https://​doi.​org/​10.​1207/​s1532​6942d​n2802_5 Roid, G. H., & Pomplun, M. (2012). The Stanford-Binet Intelligence Hunter, S. J., & Sparrow, E. P. (2012). Models of executive function- Scales, Fifth Edition. In D. P. Flanagan & P. L. Harrison (Eds.), ing. Executive Function and Dysfunction, 5–16. https://​doi.​org/​ Contemporary intellectual assessment: Theories, tests, and issues 10.​1017/​cbo97​80511​977954.​003 (pp. 249–268). The Guilford Press. Inguaggiato, E., Sgandurra, G., & Cioni, G. (2017). Brain plasticity Ronan, L., Alexander-Bloch, A., & Fletcher, P. C. (2020). Childhood and early development: Implications for early intervention in neu- obesity, cortical structure, and executive function in healthy chil- rodevelopmental disorders. Neuropsychiatrie de l’Enfance et de dren. Cerebral Cortex, 30(4), 2519–2528. https://d​ oi.o​ rg/1​ 0.1​ 093/​ l’Adolescence, 65(5), 299–306. https://​doi.​org/​10.​1016/j.​neure​nf.​ cercor/​bhz257 2017.​03.​009 Rose, S. (2022). Measurement structures of hope: A review of single- Jirout, J., LoCasale-Crouch, J., Turnbull, K., Gu, Y., Cubides, M., factor and two-factor models across hope scales. Current Opinion Garzione, S., Evans, T. M., Weltman, A. L., & Kranz, S. (2019). in Psychology, 48, 101488. https://d​ oi.o​ rg/1​ 0.1​ 016/j.c​ opsyc.2​ 022.​ How lifestyle factors affect cognitive and executive function and 101488 the ability to learn in children. Nutrients, 11(8), 1953. https://​doi.​ Rose, S. A., Feldman, J. F., & Jankowski, J. J. (2012). Implications of org/​10.​3390/​nu110​81953 infant cognition for executive functions at age 11. Psychological Johansson, M., Forssman, L., & Bohlin, G. (2014). Development and Science, 23(11), 1345–1355. https://​doi.​org/​10.​1177/0​ 9567​97612​ aging individual differences in 10-month-olds’ performance on 444902 the A-not-B task. Scandinavian Journal of Psychology, 55(2), Scionti, N., & Marzocchi, G. M. (2021). The dimensionality of early 130–135. https://​doi.​org/​10.​1111/​sjop.​12109 executive functions in young preschoolers: Comparing unidimen- Karr, J. E., Areshenkoff, C. N., Rast, P., Hofer, S. M., Iverson, G. L., & sional versus bidimensional models and their ecological validity. Garcia-Barrera, M. A. (2018). The unity and diversity of executive Child Neuropsychology, 27(4), 491–515. https://​doi.​org/​10.​1080/​ functions: A systematic review and re-analysis of latent variable 09297​049.​2020.​18684​19 studies. American Psychological Association In Psychological Soto, E. F., Kofler, M. J., Singh, L. J., Wells, E. L., Irwin, L. N., Groves, Bulletin, 144(11), 1147. https://​doi.​org/​10.​1037/​bul00​00160 N. B., & Miller, C. E. (2020). Executive functioning rating scales: 13 Advances in Neurodevelopmental Disorders Ecologically valid or construct invalid? Neuropsychology, 34(6), parenting and executive functions development in early childhood. 605–619. https://​doi.​org/​10.​1037/​neu00​00681 Developmental Science, 1–38. https://d​ oi.o​ rg/1​ 0.1​ 111/d​ esc.1​ 3293 Sparrow, E. P. (2012). Section II: EdF in the neurodevelopmental and Wiebe, S. A., Lukowski, A. F., & Bauer, P. J. (2010). Sequence imita- acquired disorders. In S. J. Hunter & E. P. Sparrow (Eds.), Execu- tion and reaching measures of executive control: A longitudinal tive function and dysfunction (pp. 91–92). Cambridge University examination in the second year of life. Developmental Neuropsy- Press. chology, 35(5), 522–538. https://d​ oi.o​ rg/1​ 0.1​ 080/8​ 75656​ 41.2​ 010.​ Tirapu-Ustárroz, J., Muñoz-Céspedes, J. M., & Pelegrín-Valero, C. 494751 (2002). Funciones ejecutivas: necesidad de una integración con- Zelazo, P. D. (2015). Executive function: Reflection, iterative repro- ceptual [Executive Functions: the Need for the Integration of cessing, complexity, and the developing brain. Developmental Concepts]. Revista de Neurología, 34(07), 673. https://​doi.​org/​ Review, Executive function: Reflection, 55–68. https://​doi.​org/​10.​ 10.​33588/​rn.​3407.​20013​11 1016/j.​dr.​2015.​07.​001 Tomaszewski, B., Hepburn, S., Blakeley-Smith, A., & Rogers, S. J. Zelazo, P. D. (2020). Executive function and psychopathology: A (2020). Developmental trajectories of adaptive behavior from neurodevelopmental perspective. Annual Review of Clinical toddlerhood to middle childhood in autism spectrum disorder. Psychology, 16, 431–454. https://​doi.​org/​10.​1146/​annur​ev-​clinp​ American Journal on Intellectual and Developmental Disabilities, sy-​072319-​024242 125(3), 155–169. https://​doi.​org/​10.​1352/​1944-​7558-​125.3.​155 Zelazo, P. D., Müller, U., Frye, D., Marcovitch, S., Argitis, G., Boseo- Treat, A. E., Sheffield Morris, A., Williamson, A. C., Hays-Grudo, vski, J., Chiang, J. K., Hongwanishkul, D., Schuster, B. V., & J., & Laurin, D. (2019). Adverse childhood experiences, parent- Sutherland, A. (2003). The development of executive function ing, and child executive function. Early Child Development and in early childhood. Monographs of the Society for Research in Care, 189(6), 926–937. https://​doi.​org/​10.​1080/​03004​430.​2017.​ Child Development, 68(3), vii–137 http://​www.​ncbi.​nlm.​nih.​gov/​ 13539​78 pubmed/​14723​273 Waters, N. E., Ahmed, S. F., Tang, S., Morrison, F. J., & Davis-Kean, P. E. (2021). Pathways from socioeconomic status to early aca- Publisher’s Note Springer Nature remains neutral with regard to demic achievement: The role of specific executive functions. Early jurisdictional claims in published maps and institutional affiliations. Childhood Research Quarterly, 54, 321–331. https://​doi.​org/​10.​ 1016/j.​ecresq.​2020.​09.​008 Werchan, D. M., Ku, S., Berry, D., & Blair, C. (2022). Sensitive car- egiving and reward responsivity: A novel mechanism linking 13