Infants' perception of kinetic depth and stereokinetic displays.

Examined infants' perceptions of 3-dimensional form, using a kinetic depth effect (KDE) display and displays containing subsets of the motion present in the KDE display. One subset consisted of "between-contour" motion, and the second consisted of "within-contour" motion. Research with adults has suggested that only between-contour motion leads to a compelling depth percept. In Exps 1 and 2, infants generalized habituation from a KDE display to the between-contour but not the within-contour changes. In Exps 3 and 4, infants generalized habituation from a KDE display to the between-contour display viewed from a novel orientation but not to the within-contour display viewed from the original orientation. Results indicate sensitivity to between-contour but not within-contour information, suggesting that infants perceive the 3-dimensional form of these displays. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Homogeneous Sulfonation of Styrene-Divinylbenzene Copolymers with Oleum in Organic Solvents

In order to obtain homogeneously sulfonated cation exchangers, the copolymers were sulfonated by oleum in a mixture of methylene-chloride and nitromethane. The influences of the chemical interaction and of the diffusion process on the kinetic behavior of these systems were investigated, and it was shown that raising the temperature of the sulfonation mixture markedly increases the chemical reaction rate, while the effect on the diffusion is small. A curve-fitting technique was used for the interpretation of the degree-of-sulfonation-vs.-time curves. These investigations served as guidelines for the subsequent preparation of homogeneous highly sulfonated copolymers.     

Children's postural sway in response to low- and high-frequency visual information for oscillation.

Two experiments examined postural responses of 3- to 6-year-old children to visual information for oscillation. In Experiment 1, children saw oscillations of the surround, with these movements ranging in frequency between 0.2 and 0.8 Hz. Analyses of anterior-posterior postural sway revealed that, similar to previous developmental investigations, the frequency of sway matched the frequency of oscillations. Analyses of sway amplitude and timing, however, revealed patterns of results more in keeping with research on adults. Experiment 2 extended these findings, presenting oscillations in which the frequency changed during the trial. Analyses of anterior-posterior sway revealed that sway frequency matched both speeds of movement. In contrast, amplitude and timing measures were again in line with adult data. These results suggest that the postural sway of children contains both adultlike and nonadultlike parameters of balance control. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Expectancy effects in memory for melodies

Two experiments explored the relation between melodic expectancy and melodic memory. In Experiment 1, listeners rated the degree to which different endings confirmed their expectations for a set of melodies. After providing these expectancy ratings, listeners received a recognition memory test in which they discriminated previously heard melodies from new melodies. Recognition memory in this task positively correlated with perceived expectancy, and was related to the estimated tonal coherence of these melodies. Experiment 2 extended these results, demonstrating better recognition memory for high expectancy melodies, relative to medium and low expectancy melodies. This experiment also observed asymmetrical memory confusions as a function of perceived expectancy. These findings fit with a model of musical memory in which schematically central events are better remembered than schematically peripheral events.     

Perceptual Tests of an Algorithm for Musical Key-Finding.

Perceiving the tonality of a musical passage is a fundamental aspect of the experience of hearing music. Models for determining tonality have thus occupied a central place in music cognition research. Three experiments investigated 1 well-known model of tonal determination: the Krumhansl-Schmuckler key-finding algorithm. In Experiment 1, listeners' percepts of tonality following short musical fragments derived from preludes by Bach and Chopin were compared with predictions of tonality produced by the algorithm; these predictions were very accurate for the Bach preludes but considerably less so for the Chopin preludes. Experiment 2 explored a subset of the Chopin preludes, finding that the algorithm could predict tonal percepts on a measure-by-measure basis. In Experiment 3, the algorithm predicted listeners' percepts of tonal movement throughout a complete Chopin prelude. These studies support the viability of the Krumhansl-Schmuckler key-finding algorithm as well as a model of listeners' tonal perceptions of musical passages. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Detection of the traversability of surfaces by crawling and walking infants.

In four studies we investigated the perception of the affordance for traversal of a supporting surface. The surface presented was either rigid or deformable, and this property was specified either optically, haptically, or both. In Experiment 1A, crawling and walking infants were presented with two surfaces in succession: a standard surface that both looked and felt rigid and a deforming surface that both looked and felt nonrigid. Latency to initiate locomotion, duration of visual and haptic exploration, and displacement activity were coded from videotapes. Compared with the standard, the deforming surface elicited longer latency, more exploratory behavior, and more displacement in walkers, but not in crawlers, suggesting that typical mode of locomotion influences perceived traversability. These findings were replicated in Experiment 1B, in which the infant was presented with a dual walkway, forcing a choice between the two surfaces. Experiments 2, 3A and B, and 4A and B investigated the use of optical and haptic information in detecting traversability of rigid and nonrigid surfaces. Patterns of exploration varied with the information presented and differed for crawlers and walkers in the case of a deformable surface, as an affordance theory would predict. (PsycINFO Database Record (c) 2010 APA, all rights reserved)