Reflections on the study of infant perception and cognition: what does Morgan's Canon really tell us to do?

This commentary on Needham's (2001, this issue) work focuses on the types of evidence needed to make inferences concerning infant cognition. It is helpful to consider the history of the positions that have been held by scientists who have tried to explain the cognitive abilities of animals, deemed to be so very different from adult humans, and in that regard, similar to infants. The justification of inference is not a matter of personal taste or the application of a rigid doctrine. Rather, the study of infant cognition requires a high level of creativity in the creation and testing of alternative explanations. By understanding lessons from our past, current researchers should be better able to conduct their studies and draw appropriate conclusions.