Young infants can learn statistical regularities and patterns in sequences of events. Studies have demonstrated a relationship between early sequence learning skills and later development of cognitive and language skills. We investigated the relation between infants' visual response speed to novel event sequences, and their later receptive and productive vocabulary. Using a modified visual expectancy paradigm (VExP; Haith, Wentworth, & Canfield, 1993), we tested 6-month-old infants' speed at responding to novel but predictable contingent event sequences. In addition, parental reports and behavioral measures of infants' vocabulary were obtained at 12, 16, and 22 months. In order to estimate the separate effects of linguistic input on vocabulary, maternal speech from a play session at 12 months was analyzed for lexical diversity and quantity. Results suggest that infants' speed of responding to novel but predictable events at 6 months robustly predicted both receptive and productive vocabulary at 22 months. This relation cannot be attributed to general cognitive maturity, as measured by a standardized test (Bayley Scales of Infant Development; Bayley, 2005). Maternal input predicted additional unique variance in infant processing speed. The results suggest that infants' capacity to quickly learn and respond to sequential patterns, over and above the quality of the speech input they receive, contributes to vocabulary size in the second year. © 2014 Copyright Taylor & Francis Group, LLC.

Background

The Adolescent Brain Cognitive Development ™ Study (ABCD Study®) is an open-science, multi-site, prospective, longitudinal study following over 11,800 9- and 10-year-old youth into early adulthood. The ABCD Study aims to prospectively examine the impact of substance use (SU) on neurocognitive and health outcomes. Although SU initiation typically occurs during teen years, relatively little is known about patterns of SU in children younger than 12.

Methods

This study aims to report the detailed ABCD Study® SU patterns at baseline (n = 11,875) in order to inform the greater scientific community about cohort's early SU. Along with a detailed description of SU, we ran mixed effects regression models to examine the association between early caffeine and alcohol sipping with demographic factors, externalizing symptoms and parental history of alcohol and substance use disorders (AUD/SUD).

Primary results

At baseline, the majority of youth had used caffeine (67.6 %) and 22.5 % reported sipping alcohol (22.5 %). There was little to no reported use of other drug categories (0.2 % full alcohol drink, 0.7 % used nicotine, <0.1 % used any other drug of abuse). Analyses revealed that total caffeine use and early alcohol sipping were associated with demographic variables (p's<.05), externalizing symptoms (caffeine p = 0002; sipping p = .0003), and parental history of AUD (sipping p = .03).

Conclusions

ABCD Study participants aged 9-10 years old reported caffeine use and alcohol sipping experimentation, but very rare other SU. Variables linked with early childhood alcohol sipping and caffeine use should be examined as contributing factors in future longitudinal analyses examining escalating trajectories of SU in the ABCD Study cohort.