Guided by evolutionary-developmental models, this study tested the hypothesis that children's exposure to parental relationship instability, defined by initiation and dissolution of caregiver intimate relationships, has both costs in cognitive impairments and benefits in enhanced learning skills. Participants included 243 mothers and their…

As the United States experiences greater income inequality, more and more students experience an early science achievement gap. This study tested several competing theoretical models of early science achievement with a longitudinal sample of 14,624 children who were followed from kindergarten entry to the end of 1st grade. To understand why and…

Theoretical perspectives on spelling characterize development as a progression through qualitatively different phases or as a process of more or less continuous growth. This study investigated the potential utility of a different perspective, the overlapping-wave model, for characterizing spelling development (Rittle-Johnson & Siegler, 1999). In…