Ontogeny of tool use in cottontop tamarins, Saguinus oedipus:: innate recognition of functionally relevant features

Adult cottontop tamarins are sensitive to the functionally relevant and irrelevant features of objects used as tools to gain access to food. We conducted four experiments designed to assess whether infant cottontop tamarins show comparable sensitivities to functionally relevant and irrelevant features. All subjects were reared in a species-typical social environment, but prior to the present studies had never participated in any experiments, and had no access to tools or other freely moving, manipulable objects with the exception of food. Despite their lack of experience, the pattern of object choice by infants precisely mirrored those obtained with adults. Specifically, having learned to use a hard blue cane to retrieve food (experiment 1), infant tamarins immediately generalized to other objects (experiments 2-4), recognizing that changes in colour and texture play no role in an object's functionality as a tool, whereas changes in size and shape do. These data suggest that for cottontop tamarins, a species that does not naturally use tools, and infrequently manipulates objects, that the capacity to distinguish between functionally relevant and irrelevant features develops in the absence of domain-specific experience. (C) 002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.