Abstract
Similarity and categorization are usually formulated as operations over a set of available features at time t of conceptual development. In this paper, we discuss possible constraints on the development of the feature space such as the history of categorization, perceptual biases in the selection and the construction of features, and the role of higher-level knowledge and beliefs. The history of categorization is defined as the feature vocabulary and the set of concepts people have acquired as a result of representing and categorizing objects. Perceptual and developmental biases refer to the salience of specific aspects of the stimuli which influence the selection and the construction of features at different stages of development. The constraining role of general knowledge on the selection and the creation of features is also discussed. It is argued that theories may need the constraints they are supposed to provide. We conclude by discussing issues related to the interactions of perceptions and conceptions in developing feature spaces for higher-level cognition.