We tested 6- and 8-month-old White and non-White infants (N = 53 total, 28 girls) from Northern California in a visual search task to determine whether a unique item in an otherwise homogeneous display (a singleton) attracts attention because it is a unique singleton and "pops out" in a categorical manner, or whether attention instead…

We examined how infants' categorization is jointly influenced by previous experience and how much they shift their gaze back and forth between stimuli. Extending previous findings reported by K. A. Kovack-Lesh, J. S. Horst, and L. M. Oakes (2008), we found that 4-month-old infants' (N = 122) learning of the exclusive category of "cats" was related…

Six-month-old infants' ("N" = 168) memory for individual items in a categorized list (e.g., images of dogs or cats) was examined to investigate the interactions between visual recognition memory, working memory, and categorization. In Experiments 1 and 2, infants were familiarized with six different cats or dogs, presented one at a time…

Habituation of looking time has become the standard method for studying cognitive processes in infancy. This method has a long history and derives from the study of memory and habituation itself. Often, however, it is not clear how researchers make decisions about how to implement habituation as a tool to study processes such as categorization,…

When learning object function, infants must detect relations among features--for example, that squeezing is associated with squeaking or that objects with wheels roll. Previously, Perone and Oakes (2006) found 10-month-old infants were sensitive to relations between object appearances and actions, but not to relations between appearances and…

Two experiments demonstrate that 14- to 18-month-old toddlers can adaptively change how they categorize a set of objects within a single session, and that this ability is related to vocabulary size. In both experiments, toddlers were presented with a sequential touching task with objects that could be categorized either according to some…

We examined the effect of 4-month-old infants' previous experience with dogs, cats, or both and their online looking behavior on their learning of the adult-defined category of "cat" in a visual familiarization task. Four-month-old infants' (N = 123) learning in the laboratory was jointly determined by whether or not they had experience…

We investigated how exposure to pairs of different items (as compared with pairs of identical items) influences 10-month-olds' (n=79) categorization of horses versus dogs in an object-examining task. Infants responded to an exclusive category when familiarized with pairs of different items but not when familiarized with pairs of identical items…

Despite a large body of research demonstrating the kinds of categories to which infants respond, few studies have directly assessed how infants' categorization unfolds over time. Four experiments used a visual familiarization task to evaluate 10-month-old infants' (N=98) learning of exemplars characterized by commonalities in appearance or…

Three experiments directly compared infants' categorization in variations of the visual familiarization task. In each experiment, 4- or 6-month-old infants were familiarized with a collection of dogs or cats and then their response to novel dogs and cats was assessed. In Experiment 1, 4-month-old infants responded to the exclusive distinction of…

Infants were familiarized with plastic animals from one of two categories (land or sea) that were judged similar or variable by adults. Infants were then tested with novel animals from the same or a different category. Thirteen-month-olds in the similar familiarization condition dishabituated to novel animals of a different category and, to a…

Responds to Mandler's critique of authors' view of infant categorization. Maintains that their view of infant categorization is not characterized by a shift from one type of category to another but by gradual changes in the kinds of information infants can use in forming categories. Clarifies position regarding a single categorical process using…

Demonstrates the need for a process-oriented, constructivist approach to understanding infants' categorization abilities. Suggests that emphasizing the distinction between perceptual and conceptual categorization has been an obstacle to forging an approach. Proposes a more microanalytic consideration of features available to infants at different…

A sequential-touching task was used to investigate whether 14-month-old infants can rapidly change how they categorize a set of objects, recognizing new groupings of objects they had previously categorized in a different way. When presented with a collection of objects that could be categorized by shape (balls vs. blocks) or material (soft vs.…

Calls for a process-oriented approach to study of categorization in infancy. Maintains that further understanding of infant categorization and its changes with development requires a more direct assessment of infants' category formation. Argues that two research directions will enhance understanding of categorization: (1) contextual variations on…