Converging operations revisited: assessing what infants perceive using discrimination measures.

The study of visual perception in human infants is confronted by a number of special problems arising from the inaccessibility of verbal reports. In this paper, we discuss the experimental strategy of converging operations in the context of investigating the phenomenal experience of infants. The goal of this strategy is to logically and empirically delimit alternative explanations for a given behavior. Knowledge about the mature functioning of a perceptual competence, as well as knowledge about its developmental course, constrains the selection of viable explanations, but cannot produce a unique interpretation. This goal is pursued through the implementation of an iterative strategy in which competing interpretations are tested until only one plausible alternative remains. A series of experiments investigating infants' sensitivity to biomechanical motions are reviewed as a way of illustrating how this methodology is operationalized.