The natural pedagogy hypothesis proposes that human infants preferentially attend to communicative signals from others, facilitating rapid cultural learning. In this view, sensitivity to such signals is a uniquely human adaptation and as such nonhuman animals should not produce or utilize these communicative signals. We test these evolutionary…

It has been suggested that due to functional similarity, sortal object individuation might be a primordial form of psychological essentialism. For example, the relative independence of identity judgment from perceived surface features is a characteristic of essentialist reasoning. Also, infants engaging in sortal object individuation pay more…

Adults preferentially use information from the left side of face images to judge gender, emotion, and identity. In this study, we examined the development of this visual-field bias over middle childhood (5-10 years). Our goal was to both characterize the developmental trajectory of the left-side bias (should one exist) and examine the selectivity…

A theory of how concept formation begins is presented that accounts for conceptual activity in the first year of life, shows how increasing conceptual complexity comes about, and predicts the order in which new types of information accrue to the conceptual system. In a compromise between nativist and empiricist views, it offers a single…

Spatial construction tasks are basic tests of visual-spatial processing. Two studies have assessed spatial construction skills in chimpanzees (Pan troglodytes) and young children (Homo sapiens sapiens) with a block modelling task. Study 1a subjects were three young chimpanzees and five adult chimpanzees. Study 1b subjects were 30 human children…

A milestone in human development is coming to recognize that how something looks is not necessarily how it is. We tested appearance-reality understanding in chimpanzees ("Pan troglodytes") with a task requiring them to choose between a small grape and a big grape. The apparent relative size of the grapes was reversed using magnifying and…