People change – across years, weeks, hours, and even seconds. The impetus of the work in the lab is to accurately describe these changes and to identify the factors that influence their unfolding. Because development concerns change over time and because girls and boys change in different ways (Beltz, Blakemore, & Berenbaum, 2013), there is particular emphasis on time-indexed analysis methods and on gendered developmental processes in the research conducted in the lab. For example, significant brain and behavioral changes occur during adolescence, and many of these changes are associated with puberty – a sex-typed biological process that has unique social consequences for boys and girls. Lab-related work shows that cognitive and affective consequences of pubertal timing persist into early adulthood via different mechanisms for girls and boys (Beltz, 2018; Beltz & Berenbaum, 2013), and that an understanding of how puberty differentially affects adolescent changes in girls and boys can depend upon the statistical models used to characterize pubertal development (Beltz, Corley, Bricker, Wadsworth, & Berenbaum, 2014).