Individual Differences in Executive Function from 14 to 24 Months

• In Event: 3-203 - Development of Self-Regulation in Infancy and Toddlerhood

Integrative Statement

Introduction and Aims
Children’s ability to control their own thoughts and actions, or ‘executive function’ (EF), has been a topic of intense interest in the field of developmental science for the past two decades but relatively little attention has centered on individual differences in EF in the first two years of life. Unlike studies of preschool children, small-scale studies using EF task batteries in the first two years of life indicate little overlap between EF tasks and only limited rank-order stability over time (e.g., Miller & Marcovitch, 2015). Our first aim was to extend the current literature using a large-scale longitudinal study to investigate the relations EF tasks at 14 and 24 months and the longitudinal stability of EF across this period.
Aspects of temperament, such as effortful control (i.e., regulation of motor behaviour, attention and emotion) and negative affect (i.e., poor emotional regulation in response to environmental change) are conceptually overlapping with EF but the links between these constructs have yet to be investigated in the first two years of life (Hendry et al., 2016). Likewise, children’s language ability is hypothesised to underpin the development of self-regulation (Vygotsky, 1978) but relations between language and EF have yet to be studied in the second year of life. Our second and third aims were therefore to investigate the associations between temperament, language ability and EF at 14 and 24 months.

Sample. 438 typically developing infants (218 boys) from the UK, USA and the Netherlands participated in home visits as part of a large longitudinal study when they were 14 months old (M = 14.42 months, SD = 0.57) and 24 months old (M = 24.47 months, SD = 0.79).

Method. At 14 months infants completed a battery of three age-appropriate EF tasks based on standard paradigms: the Prohibition Task (a measure of inhibition – Friedman et al., 2011), the Multi-Location Search Task (a measure of working memory – Diamond et al., 1997), and the Ball Run Task (a measure of shifting). At 24 months infants completed the same tasks alongside the Baby Stroop task (a measure of conflict inhibition – Hughes & Ensor, 2005). Parents rated infant negative affect and effortful control at 14 and 24 months using the Early Childhood Behavior Questionnaire (Putnam, Garstein & Rothbart, 2006). Language ability was measured at 14 months using the MCDI (Fenson et al., 1994) and at 24 months using both the MCDI and the WPPSI receptive vocabulary test (Wechsler, 2003).

Results. There were marked individual differences in performance on EF tasks at both 14 and 24 months. Correlations revealed little evidence of cohesion among EF tasks at 14 months but stronger associations at 24 months (Table 1). Regression models indicated no evidence for longitudinal stability in EF. There was no consistent evidence for either concurrent or longitudinal associations between EF and temperament or between EF and language ability (Table 2). As the largest study of its kind, our results add to a growing body of research on EF in the first two years of life.

Group Authors

The New Fathers and Mothers Study

Authors

• Rory Thomas Devine, University of Birmingham
  Presenting Author

• Claire Hughes, University of Cambridge
  Non-Presenting Author