In this study, we examined the hypothesis that preschoolers' performance on emotion and cognitive tasks is organized into discrete processes of control and understanding within the domains of emotion and cognition. Additionally, we examined the relations among component processes using mother report, behavioral observation, and physiological measures of emotion control. Participants were 263 children (42 percent non-White) and their mothers. Results indicated that the three approaches of measuring emotion control were unrelated. Regardless of the measurement method, a four-factor solution differentiating emotion control and understanding and cognitive control and understanding fits the data better than did either of two two-factor models, one based on domains of emotion and cognition across processes, and one based on processes of control and understanding across domains. Results of this research replicate those of Leerkes et al. in describing a differentiated underlying structure of emotion and cognition processes in early childhood while also extending these conclusions across samples and across measurement approaches for assessing emotion control. (Contains 4 tables and 1 figure.)