This study examined the coevolution of prosocial and aggressive popularity norms with popularity hierarchy (asymmetries in students' popularity). Cross-lagged-panel analyses were conducted on 2,843 secondary school students (N[subscript classrooms] = 120; M[subscript age] = 13.18; 51.3% girls). Popularity hierarchy predicted relative change in…

Three studies examined preschool children's understanding of categorical hierarchies, testing their ability to form categories at different levels of generality and to include the same objects in multiple categories. Found that, contrary to the implications of previous studies, two- and three-year olds appear to have both categorization skills.…

Three experiments explored four and seven year olds' and adults' knowledge of taxonomy, including horizontal relations between items at the same hierarchical level and vertical relations between items at different hierarchical levels. Results showed that four year olds' taxonomic knowledge was restricted to one type of horizontal relationship. (BC)

Examines the relative utility of exemplar and linguistic information for acquiring basic and superordinate categories. Developmental differences were predicted in the ability to benefit from the linguistically specified information. Preschool, kindergarten, and first-grade children were tested. (Author/SS)

Asked children and adults to recall events from "Sesame Street." Found that subjects' memory was influenced by causal factors (number of causal relations to other events, place in the story's causal chain) and this influence increased with age; children recalled actions, whereas adults recalled protagonists' goals; and children's recall…

Two studies of development of spatial representation with two dimensions found that children as young as five years use the same two independent dimensions in fine-grained spatial coding of location in a circle as adults use--radius and angle. The adult pattern, where angle as well as radius is coded hierarchically, emerges by nine years. (HTH)