Genetics and Environment
Young children vary considerably in their readiness to learn to select behaviours that lead to reward and avoid behaviours that lead to failure. Some children, for example, are impulsive and act quickly given the prospect of immediate reward. Other children are more reticent, and hesitate given the prospect of failure. Interestingly, these differences in cognitive and behavioural self-regulation early in development are a strong predictor of later psychological, social, and physical well-being. Understanding their origin is therefore a priority for both basic and applied developmental scientists.
Research to date has focused largely on either the gentic or enviornmental contributions to such differences. Our current project is unique in that it examines how genetics and experience interact to produce differences in self-regulation early in development at the level of both brain and behaviour. To this end, we are combining data obtained from DNA, behavioural measures of self-regulation, and fMRI-based measures of brain activity. This multi-modal perspective will allow us to unravel some of the complexity surrounding questions such as what ultimately makes us who we are, and how developmental processes contribute to who we eventually become.
Bilingual Language Status and Collectivist/Individualist Cultural Values
Children vary widely in terms of how effectively they can regulate their thoughts and behaviours. Whereas some children have little difficulty focusing on assigned tasks, others are easily distracted by irrelevant or misleading information. Understanding why children differ in their capacity for self-regulation is important because a child's capacity to focus on assigned tasks is predictive of their future academic achievement and social adjustment.
On some accounts, growing up speaking two languages rather than one gives children a slight advantage in problems of self-regulation. Bilingual children, for example, appear to be less vulnerable to distraction than their monolingual counterparts, even in tasks that do not involve language. This so-called bilingual advantage in cognitive control has been attributed to a lifetime of practice managing separate language systems, experience which is unique to bilingual children and which is thought to strengthen children's capacity for self-regulation.
One important shortcoming of available evidence however is that bilingual and monolingual children differ in a variety of ways beyond simply language status. Beyond speaking two languages rather than one, bilingual children in many seminal studies are immigrants from cultures with highly collectivistvalues whereas monolingual children are non-immigrant members of cultures with individualist values. Bilingual and monolingual children may have differed in other ways as well, such as in terms ofsocio-economic status, although we don't know for certain as these socio-cultural variables are typicallynot measured.
In order to properly understand the nature of the bilingual advantage, and to gain insight into the development of self-regulation, it is critically important that the possible effects of bilingual language status be disentangled from the effects of socio-cultural influences like cultural values and socio-economic status. Differences in cultural value systems and socio-economic status are both associated with differences in self-regulation. Moreover, emerging evidence suggests that when these factors are more carefully controlled, the bilingual advantage is either significantly attenuated or absent altogether.
The goal of the proposed study is to disentangle the effects of cultural values and language status on children's capacity for self-regulation through a comparison of bilingual and monolingual children from cultures with collectivist (Arabic children from Lebanon) and individualist (Caucasian children fromCanada) value systems.
Development of Fluid Intelligence
Questions concerning the growth of human intelligence have occupied great minds in psychology for over 100 years. Recent advances in the theoretical characterization of human intelligence and methods for probing its genetic and neurophysiological correlates create an unprecedented opportunity to trace the developmental origins of this foundational aspect of our cognitive phenotype. The current study will provide a baseline measure of the growth of two facets of higher-intelligence -- Reasoning and Short-term memory -- which will in turn establish a database to support future investigations of the growth of intelligence.
This study is a longitudinal investigation of the development of fluid intelligence. Children aged 6- to 12-years of age complete an on-line battery of short engaging computer tasks designed to measure fluid intelligence. Multiple measures will be collected from each participant over the course of 5 years. Findings provide insight into the normative growth trajectory of higher-order thought and will form the basis of future investigations of genetic, experiential, and neurophysiological correlates of the growth of intelligence.