In this chapter, we examine how language relates to executive function (EF) in preschoolers. EF consists of higher cognitive functions that are involved in the control of thought, action, and emotion and that have been linked to neural systems involving the prefrontal cortex. Despite its importance, the meaning of EF has remained elusive (Lehto, Juujäarvi, Kooistra, & Pulkkinen, 2003). Broadly defined, EF is “an umbrella term for all of the complex set of cognitive processes that underlie flexible goal-directed responses to novel or difficult situations” (Hughes & Graham, 2002, p. 131). Recent empirical work has clarified the composition and development of EF. Factor analytic studies have identified working memory, flexibility, and inhibition as three key components of executive function (Lehto et al., 2003; Miyake et al., 2000).
EF and its development has recently received considerable attention in developmental psychology, and several studies have charted the developmental trajectory of children's performance on numerous EF tasks (see Diamond, 2002; Zelazo & Müller, 2002, for reviews). This interest has been driven by findings that (a) EF is implicated in various developmental disorders such as autism (e.g., Hill, 2004; Pennington & Ozonoff, 1996; Russell, 1997) and attention-deficit hyperactivity disorder (e.g., Barkley, 2004; Mulas, Capilla, & Fernández, 2006), and (b) the development of executive function is significantly correlated with the development of social understanding, specifically false belief understanding (e.g., Frye, Zelazo, & Palfai, 1995; Perner & Lang, 1999; Sabbagh, Xu, Carlson, Moses, & Lee, 2006).