The relationships among working memory, inhibition and temperament in the third year of life

Abstract

The third year of life depicts the transition period during which children gradually become more competent in controlling their thoughts and emotions. Recent studies with preschool children suggest that delay inhibition and conflict inhibition are the two types of inhibition, the former requiring the child to suppress a dominant behavior, while the latter requiring not only to suppress it but also to enact a subdominant behavior conflicting with it. The aim of the present study is to investigate whether or not delay inhibition and conflict inhibition relate to working memory and temperament differentially in younger children. Thirty-four Turkish children aged 24-to-36 months and their mothers participated in the study. Two separate sessions were arranged for each child individually. For half of the children, the first session involved Imitation Sorting Tasks (IST) as the working memory measure, and the second involved a total of six inhibition measures including three tasks for delay inhibition and three for conflict inhibition; whereas for the other half, the order of the sessions were reversed. The mothers rated temperament of their children on the very short form of Early Childhood Behavior Questionnaire (ECBQ). Using hierarchical regression, it was found that working memory capacity predicted conflict inhibition performance beyond delay inhibition performance even when controlled for age. Contrary to the expectations, temperamental characteristics measured by the ECBQ in terms of negative affectivity, surgency and effortful control did not predict delay inhibition performance. Nor there was any relationship between conflict inhibition performance and any of the temperamental characteristics. However, there was a significant association between conflict and delay inhibition even after age was controlled. These results support both the distinction and the relation between delay inhibition and conflict inhibition as well as highlight the role of working memory capacity in predicting conflict inhibition performance in the third year of life.