What Is (Are) Executive Function(s)? Insights From Individual Differences Research

Naomi Friedman

Executive functions are high-level cognitive processes that enable control over thoughts and actions through their regulation of lower-level processes. They are central to many areas of psychology, including research on psychopathology, development, aging, and bilingualism, to name a few. Yet there is still considerable variability in how researchers measure these abilities, and how they conceptualize the cognitive and neural mechanisms that underlie individual differences in performance on executive tasks. Part of this variability stems from the fact that executive functioning is not a single ability, but rather is a family of interrelated but separable abilities. I will present an overview of one well-replicated model, the unity/diversity model, which describes the relationships among three of the most frequently studied executive functions: response inhibition, working memory updating, and task switching. The model is so named because these abilities show some unity, in that a common factor influences individual differences in all three, but also show diversity, in that there are also specific factors that influence individual differences in working memory updating and task switching. After discussing the genetic and environmental influences on these unity and diversity components, and what they may be measuring in terms of cognitive mechanisms, I will discuss implications and recommendations for incorporating them into bilingualism research.