In the McGurk effect, perceptual identification of auditory speech syllables is influenced by simultaneous presentation of discrepant visible speech syllables. This effect has been found in subjects of different ages and with various native language backgrounds. But no McGurk tests have been conducted with prelinguistic infants. In the present series of experiments, 5-month-old English-exposed infants were tested for the McGurk effect. Infants were first gaze-habituated to an audiovisual /va/. Two different dishabituation stimuli were then presented: audio /ba/-visual /va/ (perceived by adults as /va/), and audio /da/-visual /va/ (perceived by adults as /da/). The infants showed generalization from the audiovisual /va/ to the audio /ba/-visual /va/ stimulus but not to the audio /da/-visual /va/ stimulus. Follow-up experiments revealed that these generalization differences were not due to a general preference for the audio /da/-visual /va/ stimulus or to the auditory similarity of /ba/ to /va/ relative to /da/. These results suggest that the infants were visually influenced in the same way as English-speaking adults are visually influenced.

Speech perception is inherently multimodal. Visual speech (lip-reading) information is used by all perceivers and readily integrates with auditory speech. Imaging research suggests that the brain treats auditory and visual speech similarly. These findings have led some researchers to consider that speech perception works by extracting amodal information that takes the same form across modalities. From this perspective, speech integration is a property of the input information itself. Amodal speech information could explain the reported automaticity, immediacy, and completeness of audiovisual speech integration. However, recent findings suggest that speech integration can be influenced by higher cognitive properties such as lexical status and semantic context. Proponents of amodal accounts will need to explain these results.

Isolated kinematic properties of visible speech can provide information for lipreading. Kinematic facial information is isolated by darkening an actor's face and attaching dots to various articulators so that only moving dots can be seen with no facial features present. To test the salience of these images, experiments were conducted to determine whether they could visually influence the perception of discrepant auditory syllables. Results showed that these images can influence auditory speech and that this influence is not dependent on subjects' knowledge of the stimuli. In other experiments, single frozen frames of visible syllables were presented with discrepant auditory syllables to test the salience of static facial features. Results suggest that while the influence of the kinematic stimuli was perceptual, any influence of the static featural stimuli was likely based on subject misunderstanding or post-perceptual response bias.

Objects for throwing to a maximum distance were selected by hefting objects varying in size and weight. Preferred weights increased with size reproducing size-weight illusion scaling between weight and volume. In maximum distance throws, preferred objects were thrown the farthest. Throwing was related to hefting as a smart perceptual mechanism. Two strategies for conveying high kinetic energy to projectiles were investigated by studying the kinematics of hefting light, preferred, and heavy objects. Changes in tendon lengths occurring when objects of varying size were grasped corresponded to changes in stiffness at the wrist. Hefting with preferred objects produced an invariant phase between the wrist and elbow. This result corresponded to an optimal relation at peak kinetic energy for the hefting. A paradigm for the study of perceptual properties was compared to size-weight illusion methodology.A task familiar to many from childhood is that of standing on a beach, in a field, or on a cliff and selecting, by hefting, the stone that can be thrown the farthest distance. Like the perfect skipping stone, the optimal throwing stone evokes an ardent glow of confidence in one's ability to discover and use this appealingly simple, yet distinct tool. What is the optimal throwing stone? Assuming a spherical shape and a fairly homogeneous mass distribution, the relevant object properties are size and weight. What is the appropriate configuration of size and weight and how is it determined? Are people truly able to select from objects varying in size and weight those optimal for throwing to a maximum distance? If so, how?The human perception-action system has been described as a system that temporarily assembles smart, special purpose, deterministic machines over relevant physical properties of the organism and the environment to perform specific tasks

A study is reported in which it is shown that observers can use at least three types of acoustic variables that indicate reliably when a moving sound source is passing: interaural temporal differences, the Doppler effect, and amplitude change. Each of these variables was presented in isolation and each was successful in indicating when a (stimulated) moving sound source passed an observer. These three variables were put into competition (with each indicating that closest passage occurred at a different time) in an effort to determine their relative importance. It was found that amplitude change dominated interaural temporal differences which, in turn, dominated the Doppler effect stimulus variable. The results are discussed in terms of two interpretations. First, it is possible that subjects based their judgements on the potential discriminability of each stimulus variable. However, because the stimuli used involved easily discriminable changes, subjects may instead have based their judgements on the independence of a stimulus variable from different environmental situation conditions. The dominance ordering obtained supports the second interpretation.