Why is instructional gesture ineffective in some contexts? And what is it about learners that predicts whether they will learn from gestures? This between-subjects linear measurement training study compares gesture instruction to two controls--operant action and transient action--in a diverse sample of first-grade students (N = 174, M[subscript…

For many decades, tool use has been viewed primarily as a cognitive achievement, an ability that separates not only adults and older children from infants, but humans from virtually all other species. According to this standard account, tool use and associated means-ends behaviors are dependent on symbolic or representational thinking. Organisms…

Language and social interactions were examined between a father and mother and their twin children, one with Down syndrome and one developing typically. Systematic observations were made of videotaped segments and coded in real time using a computerized behavior coding program. Codes for the parents' interactions consisted of total vocalizations,…