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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.

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 nonadult-like parameters of balance control.

This paper concerns how motor actions are neurally represented and coded. Action planning and motor preparation can be studied using a specific type of representational activity, motor imagery. A close functional equivalence between motor imagery and motor preparation is suggested by the positive effects of imagining movements on motor learning, the similarity between the neural structures involved, and the similar physiological correlates observed in both imaging and preparing. The content of motor representations can be inferred from motor images at a macroscopic level, based on global aspects of the action (the duration and amount of effort involved) and the motor rules and constraints which predict the spatial path and kinematics of movements. A more microscopic neural account calls for a representation of object-oriented action. Object attributes are processed in different neural pathways depending on the kind of task the subject is performing. During object-oriented action, a pragmatic representation is activated in which object affordances are transformed into specific motor schemas (independently of other tasks such as object recognition). Animal as well as human clinical data implicate the posterior parietal and premotor cortical areas in schema instantiation. A mechanism is proposed that is able to encode the desired goal of the action and is applicable to different levels of representational organization.

Studies 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 Experiments 1 and 2, infants generalized habituation from a KDE display to the between-contour but not the within-contour changes. In Experiments 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.

The observation that natural curves and surfaces are often fractal suggests that people may be sensitive to their statistical properties. The perceptual protocols that underlie discrimination between fractals and between other types of random contour and fractals are examined. Discrimination algorithms that have precisely the same sensitivities as human observers are constructed. These algorithms do not recognize the integrated scale hierarchy intrinsic to fractal form and operate by imposing a metatheory of structure that is based on a signal-noise distinction. The success of the algorithms implies that (a) self-affinity in random fractals is not perceptually recovered and (b) people have a natural disposition to view contour in terms of signal and noise. The authors propose that this disposition be understood as a principle of perceptual organization.

A series of experiments examined auditory contour formation, investigating listeners' sensitivities to a family of random fractals known as fractional Brownian noises. Experiments 1A and 1B looked at identification of contours when 3 different noises were portrayed using variations in the pitch, duration, or loudness of successive notes of a sequence. Listeners could categorize pitch and loudness encodings, but not duration mappings. Experiment 2 looked at the effect of simultaneous presentation of pitch and loudness information, finding that these dimensions combined additively to increase identification of the noise distributions. Experiment 3 looked at discrimination of pitch contours as a function of changing fractal dimension. Discrimination curves approximated an inverted U shape, a finding that is not understandable in terms of sensitivity to differences in fractal dimension per se, nor in terms of 'tuned' perceptual sensitivity to statistical regularities of the environment.

Jeannerod (1994) advocates studying motor images to understand the representation of action. We identify an unsettled issue that complicates the use of motor images to study the representation of action and present some evidence for a clear absence of equivalence between motor imagery, and movement preparation. We then elaborate and emphasize the relevance of the mental practice literature, which was introduced in the first round of commentary. Finally, we suggest two methods that will allow motor imagery theorists to address these points.