Accurate perception of emotional (facial) expressions is an essential social skill. It is currently debated whether emotion categorization in infancy emerges in a "broad-to-narrow" pattern and the degree to which language influences this process. We used an habituation paradigm to explore (a) whether 14- and 18-month-old infants perceive…

The Japanese language has single/geminate obstruents characterized by durational difference in closure/frication as part of the phonemic repertoire used to distinguish word meanings. We first evaluated infants' abilities to discriminate naturally uttered single/geminate obstruents (/pata/ and /patta/) using the visual habituation-dishabituation…

Behne, Carpenter, Call, and Tomasello (2005) showed that 9- to 18-month-olds, but not 6-month-olds, differentiated between people who were unwilling and unable to share toys. As the outcome of the two tasks is the same (i.e., the toy is not shared), the infants must respond to the different goals of the actor. However, visual habituation paradigms…

When are the precursors of ordinal numerical knowledge first evident in infancy? Brannon (2002) argued that by 11 months of age, infants possess the ability to appreciate the greater than and less than relations between numerical values but that this ability experiences a sudden onset between 9 and 11 months of age. Here we present 5 experiments…

Three habituation experiments examined the necessary conditions under which infants invoked the principle of rational action, interpreting behavior as goal-directed action. Found that the rational action principle operated at 9 months but not at 6 months. Perceptual cues indicating agency were not necessary prerequisites for a goal-directed…

Three experiments used a familiarization/novelty or a habituation/dishabituation procedure to examine developmental change in infants' tendency to parse exemplars into separate categories. Results indicated that 10-month olds appeared to form differentiated categories, whereas 4- and 7-month olds formed a single category to include the range of…

A recognition-based paradigm was used to investigate possibility that past research failed to sensitively assess infants' perception of the unity of misaligned edges in partial occlusion displays. Results suggested that habituation designs tapping recognition processes may be particularly efficacious in revealing infants' perceptual organization.…

Two experiments examined development of the ordinality concept in infants. Found that 11-month-olds successfully discriminated, whereas 9-month-olds failed to discriminate sequences that descended in numerical value from sequences increasing in numerical value. Nine-month-olds could discriminate the ordinal direction of sequences that varied in…

Assessed development of infants' sensitivity to two nested amodal temporal relations in audible and visible events. Found that sensitivity to synchrony was present by 4 weeks, remaining stable across age. Sensitivity to composition emerged by 7 weeks, increasing dramatically with age. Noted pattern of increasing specificity in perception…

Examines differences in habituation in a visual attention task as a function of chronological age, mental age, and handicapping condition. Subjects were 102 children who ranged in age from 3 to 36 months and who were classified as Down Syndrome, cerebral palsied, developmentally delayed, or multiply handicapped. (Author/RH)

Two experiments investigated whether preverbal infants distinguish between humans and mammals. Study 1 found that 7-, 9-, and 11-month-olds distinguished humans from mammals in an object-examination task. Study 2 found that 7-month-olds but not 5-month-olds showed evidence for category discrimination with the 2-dimensional color photos of toy…

Examined predictive validity of measures of infant habituation and later aspects of temperament. Found babies who habituated sooner (fewer trials to criterion) at five months of age and had fewer peak fixations during habituation were rated by mothers as more active, intense, and negative in mood, and less persistent and adaptable. Age differences…

Two experiments investigated infants' sensitivity to amount of continuous quantity and to changes in amount of continuous quantity. Found that 6-month-olds looked significantly longer at a novel quantity than at the familiar quantity. Nine-month-olds looked significantly longer at an impossible event than at a possible event. Findings question…

Three experiments investigated 4-, 6-, and 8-month-olds' perception of the audible, visible, and combined attributes of bimodally specified syllables. Results suggested that at 4 months, infants attended primarily to the featural information, at 6 months primarily to the asynchrony, and at 8 months to both features independently. (Author/KB)