Eisenberg and her colleagues found that 4- to 6-year old boys with good attentional control tend to deal with anger by using nonhostile verbal methods rather than overt aggressive methods (Eisenberg, Fabes, Nyman, Bernzweig, & Pinulas, 1994). In line with these data, the work by Kochanska and colleagues over the past decade has shown that effortful control plays an important role in the development of conscience. In studies of temperament and conscience, the early internalization of moral principles appears to be facilitated in fearful preschool-age children, es574 RUEDA, POSNER, ROTHBART pecially when their mothers use gentle discipline (see Kochanska, 1991, 1995, 1997). In addition, internalized control is greater in children who are high in effortful control (Kochanska, Murray, & Harlan, 2000; Kochanska, Murray, Jacques, Koenig, & Vandegeest, 1996). Individual differences in effortful control are also related to aspects of metacognitive knowledge, such as theory of mind (i.e., knowing that people’s behavior is guided by their beliefs, desires, and other mental states; Carlson & Moses, 2001). Tasks that require inhibitory control are correlated with performance on theory of mind tasks even when other factors such as age, planning skills, and receptive vocabulary are factored out (Carlson, Moses, & Claxton, 2004). All these data point to the idea that effortful control serves as the basis for the development from more reactive to more self-regulative behavior. Systems of effortful control may contribute to this development by providing the attentional flexibility required to manage negative affect, consider potential actions in light of moral principles, and coordinate reactions that are under voluntary control (Rothbart & Rueda, 2005).