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…

Two experiments examined whether 4-month-olds (n = 120) who were induced to assign two objects to different categories would then be able to take advantage of these contrastive categorical encodings to individuate and track the objects. In each experiment, infants first watched functional demonstrations of two tools, a masher and tongs (Experiment…

Category information is used to predict properties of new category members. When categorization is uncertain, people often rely on only one, most likely category to make predictions. Yet studies of perception and action often conclude that people combine multiple sources of information near-optimally. We present a perception-action analog of…

The development of the ability to categorize speech sounds is often viewed as occurring primarily during infancy via perceptual learning mechanisms. However, a number of studies suggest that even after infancy, children's categories become more categorical and well defined through about age 12. We investigated the cognitive changes that may be…

Adults' judgments of another person's gaze reflect both sensory (e.g., perceptual) and nonsensory (e.g., decisional) processes. We examined how children's performance on a gaze categorization task develops over time by varying uncertainty in the stimulus presented to 6- to 11 year-olds (n = 57). We found that younger children responded…

To examine key parameters of the initial conditions in early category learning, two studies compared 5-month-olds' object categorization between tasks involving previously unseen novel objects, and between measures within tasks. Infants in Experiment 1 participated in a visual familiarization-novelty preference (VFNP) task with two-dimensional…

Two experiments examined infants' ability to form a spatial category when habituated to few (only 2) or many (6) exemplars of a spatial relation. Sixty-four infants of 10 months and 64 infants of 14 months were habituated to dynamic events in which a toy was placed in a consistent spatial relation ("in" or "on") to a referent…

This article presents an eye-tracking study using a novel combination of visual saliency maps and "area-of-interest" analyses to explore online feature extraction during category learning in infants. Category learning in 12-month-olds (N = 22) involved a transition from looking at high-saliency image regions to looking at more…

Several different explanations have been proposed to account for the search asymmetry (SA) for angry schematic faces (i.e., the fact that an angry face target among friendly faces can be found faster than vice versa). The present study critically tested the perceptual grouping account, (a) that the SA is not due to emotional factors, but to…

An eye tracking methodology was used to evaluate 3- and 4-year-old children's sensitivity to speaker affect when resolving referential ambiguity. Children were presented with pictures of three objects on a screen (including two referents of the same kind, e.g., an intact doll and a broken doll, and one distracter item), paired with a prerecorded…

Humans have an extremely flexible ability to categorize regularities in their environment, in part because of attentional systems that allow them to focus on important perceptual information. In formal theories of categorization, attention is typically modeled with weights that selectively bias the processing of stimulus features. These theories…

We compared the primacy of affective versus semantic categorization by using forced-choice saccadic and manual response tasks. Participants viewed paired emotional and neutral scenes involving humans or animals flashed rapidly in extrafoveal vision. Participants were instructed to categorize the targets by saccading toward the location occupied by…

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…

Although it is generally accepted that labels facilitate categorization in infancy, recent evidence suggests that infants and young children are more likely to process visual input when presented in isolation than when paired with nonlinguistic sounds or linguistic labels. These findings suggest that auditory input (when compared to a no-auditory…