Early Childhood Research Quarterly 29 (2014) 95–105 Contents lists available at ScienceDirect Early Childhood Research Quarterly Executive function and verbal self-regulation in childhood: Developmental linkages between partially internalized private speech and cognitive flexibility David Alarcón-Rubio ∗ , José A. Sánchez-Medina, José R. Prieto-García Universidad Pablo de Olavide de Sevilla, Spain a r t i c l e i n f o Article history: Received 12 February 2013 Received in revised form 29 October 2013 Accepted 4 November 2013 Keywords: Executive function Verbal mediation Private speech Cognitive development a b s t r a c t Recent studies have noted that executive function and the use of self-regulatory private speech are related in childhood, and proposed that the critical leap that occurs in the development of executive function between the ages of three and six years may be due to the onset of language-based self-regulatory func- tions at this age. This research explored the relationship between executive function and private speech in a cross-sectional study of 81 children between four and seven years of age. The children performed an executive function task, the Dimensional Change Card Sort (DCCS), and children’s use of private speech was observed during a categorization task. The results indicated that, after controlling for children’s age, gender, verbal abilities, and fluid reasoning, children’s use of partially internalized private speech dur- ing the categorization task was significantly related to the number of phases successfully passed on the DCCS task, which required them to switch between card sorting rules. Children who used more partially internalized private speech were more likely to pass the most challenging phase of the DCCS task that assesses the ability to flexibly use different sorting rules according to a higher-order rule. We discuss the role of verbal mediation in the development of cognitive flexibility and its implications for the design of intervention programs for children who possess deficits of executive function. © 2013 Elsevier Inc. All rights reserved. 1. Introduction A significant number of recent studies have analyzed the devel- opment of executive function (EF) during childhood (Brocki & Bohlin, 2004; Carlson & Meltzoff, 2008; Davidson, Amso, Cruess, & Diamond, 2006; Henning, Spinath, & Aschersleben, 2011). EF is defined as the skill set that allows the child to plan, moni- tor, and evaluate his or her performance when solving a problem (Zelazo & Frye, 1997; Zelazo, Müller, Frye, & Marcovitch, 2003). EF is an integrated construct that consists of different subcompo- nents: response inhibition, working memory, and attentional set shifting (Miyake et al., 2000; Zelazo, Carter, Reznick, & Frye, 1997). Each of these EF components develops gradually from the earliest years of life; however, researchers have frequently observed a crit- ical change in the development of EF between three and six years of age (Garon, Bryson, & Smith, 2008). Despite the consistency of the evidence regarding this qualitative change in the development ∗ Corresponding author at: Department of Social Sciences, Universidad Pablo de Olavide de Sevilla, Carretera de Utrera, Km. 1, 41013 Sevilla, Spain. Tel.: +34 954977406; fax: +34 954349199. E-mail addresses: dalarub@upo.es (D. Alarcón-Rubio), jasanmed@upo.es (J.A. Sánchez-Medina), jrprigar@upo.es (J.R. Prieto-García). of EF, there is not complete agreement on possible explanations about its nature and the mechanisms that support its occurrence. Our study’s main objective was to investigate the characteristics of this critical leap in the development of EF in early childhood by examining the relationship between children’s performance on an EF task and children’s self-regulatory private speech observed in a categorization task. The Dimensional Change Card Sort task (DCCS; Frye, Zelazo, & Palfai, 1995; Zelazo & Frye, 1997) is a simplified version of the Wis- consin Card Sort Task (WCST; Grant & Berg, 1948) that is similar in purpose and form. The DCCS is a very useful tool to evaluate the EF of children between the ages of three and six years (Carlson, 2005; Jacques, Zelazo, Kirkham, & Semcesen, 1999; Müller, Zelazo, & Imrisek, 2005). In the standard version of the DCCS task (Zelazo, 2006), children are first asked to order a series of bivalent cards according to a rule (e.g., color), the pre-shift phase. In the second phase of the task, post-shift, the sorting rule is changed (e.g., to shape). Finally, in the most advanced phase, border phase, the chil- dren are asked to use both rules at the same time depending on the presence of a third marker on the card (e.g., a black border). In the DCCS task, children’s cognitive flexibility is increasingly chal- lenged by switching from one rule to another; first, in the post-shift phase, children have to switch to the new sorting criterion and not persevere to ordering the bivalent test cards with the rule of 0885-2006/$ – see front matter © 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ecresq.2013.11.002