Size matters: Impact of item size and quantity on array choice by chimpanzees (Pan troglodytes)

The authors previously reported that chimpanzees ( Pan troglodytes ) showed a striking bias to select the larger of 2 candy arrays, despite a reversed reward contingency in which the animals received the smaller, nonselected array as a reward, except when Arabic numerals were used as stimuli. A perceptual or incentive-based interference occurred that was […]

Stages of Category Learning in Monkeys (Macaca mulatta) and Humans (Homo sapiens)

Smith and Minda (1998) and Blair and Homa (2001) studied the time course of category learning in humans. They distinguished an early, abstraction-based stage of category learning from a later stage that incorporated a capacity for categorizing exceptional category members. The present authors asked whether similar processing stages characterize the category learning of nonhuman primates. […]