A note on the nonmetric analysis of psychological intervals for an unknown ordering of stimuli

A modified version of a coordinate adjustment technique which permits the analysis of comparisons of psychological intervals for an unknown ordering of stimuli is described and compared to the original version and to TORSCA. For configurations with a large number of points, knowledge of the rank order of the stimuli does not improve the solution. For configurations with a small number of points, the performance of the new algorithm with an unknown ordering is equivalent to TORSCA.This research was supported by a grant from the Natural Sciences and Engineering Research Council of Canada.     

Effects of victim gender and physical vs. psychological trauma/injury on observers' perceptions of sexual assault and its aftereffects

Researchers have examined many underlying attitudes toward rape. Studies have focused on female victims while an increasing number of reported male rape victims has been overlooked. This study compared observers' attribution of guilt toward rape victims and their rapists. It also specified the trauma inflicted by either physical or psychological concomitants of rape victimization and compared the effect of such information on both blame and expectation of recovery. Participants were university students, primarily Caucasian, with mean ages 20.56 and 21.21 years for males and females, respectively. Female victims were judged more harshly than male victims. Length of imprisonment considered appropriate for guilty assailants was found to be greater when injury was done to one's own gender. Recovery was expected to be a lengthy process. Implications for social gender stereotyping and public attitudes concerning aftereffects of traumatic stress are discussed.

     

Adaptive Dynamics of the Leg Movement Patterns of Human Infants: II. Treadmill stepping in Infants and Adults

Infant treadmill steps have many temporal and kinematic similarities to adult walking. Kinematic similarities can result from different patterns of underlying torque, however. In this study, we used inverse dynamics to compare the patterns and contributions of active (muscle) and passive (gravity and motion-dependent) torques in the swing phase of treadmill stepping in 7-month-old infants and adults. Results indicated that adults consistently used muscle torque to initiate and terminate swing, but that passive torques accounted for leg motion during most of the swing phase. Infants, in contrast, displayed multiple patterns of torque contributions during swing. In the most frequently occurring infant pattern, muscle torque remained flexor throughout swing and joint reversals were due to the dominant passive gravitational torque. The kinetic data suggest that the temporally and kinematically similar treadmill steps produced by adults and infants do not emanate from a unique set of neural commands to the muscles, but from a flexible interplay between multiple internal as well as external elements. These data suggest that the intrinsic dynamics of the human system provide a medium out of which, given a supportive context, stable patterns can emerge spontaneously. During development, voluntary controlled movement patterns must build on these intrinsic dynamics.     

Adaptive Dynamics of the Leg Movement Patterns of Human Infants: III. Age-Related Differences in Limb Control

In this article, the development of the increasingly differentiated control of the joints necessary to transform the spontaneous leg movements of early infancy into adaptive and functional actions is described. The hypothesis-that increasing joint control requires the capability for disassociation of joint action, the active modulation of joint stiffness, and a transition from proximal to distal control of the joints-is proposed. Kinematic and kinetic analyses of the vertical kicks of infants 2 weeks, 3 months, and 7 months of age (as well as a comparative group of adults) indicated increasing joint independence as well as phase-dependent and joint-dependent control modifications. The kicks of the younger infants were dominated by a proximal control strategy and minimal adjustments of the limb energetics during the flexion and extension phases of the kick. By 7 months of age, much larger modulations of the kick phases were observed as well as increasing evidence of distal control. These results revealed kinematic and kinetic patterns of emerging limb control between 2 weeks and 7 months of age.     

Age-related changes in temporal resolution: envelope and intensity effects.

Gap-detection thresholds were determined for 10 younger and 10 older adults at two sensation levels (40 and 60 dB SL) for tone pips with Gaussian amplitude envelopes whose standard deviations were 0.5, 1, 1.5, and 2 ms. Gap-detection thresholds were larger for the older participants under all conditions. For all participants, gap-detection thresholds increased with the standard deviation of the Gaussian amplitude envelope, were relatively independent of sensation level, and were independent of the degree of hearing loss. Because spectral splatter decreases with increasing standard deviation of the Gaussian amplitude envelope, the age-related differences in gap-detection cannot be attributed to differences between how young and old listeners are affected by off-frequency cues. Furthermore, the consistent age difference in gap-detection at all amplitude envelope standard deviations was shown to be incompatible with the hypothesis that temporal integration time is longer for older listeners.     

Separation and individuation issues in psychosocial rehabilitation.

This paper utilizes the theoretical formulations of Margaret Mahler and her colleagues on separation and individuation in order to understand how to plan psycho-rehabilitation programs for emotionally disturbed adolescents and young adults. The separation-individuation process and anxiety issues are discussed and analyzed in terms of both theory and practical application.     

Binocular unmasking with unequal interocular contrast: the case for multiple Cyclopean eyes.

Under certain conditions, the detection threshold for a sinusoidal grating embedded in a noisy background may be an order of magnitude lower when binocular cues are available than when monocular cues only are present. Such binocular unmasking occurs only when the degree of interocular disparity for the target differs from that of the background. Two classes of models have been advanced to account for such unmasking. The first assumes that orientation-specific, spatial frequency channels in each eye encode the amplitude and phase of the spatial frequency component of the pattern the channel is tuned to detect. Thus, a difference in interocular disparity between target and background could result in interocular amplitude and/or phase differences in left- and right-eye spatial frequency channels. When, however, there are no disparity differences between target and background, there will be no interocular differences in amplitude and phase in the left- and right-eye channels. In this model, then, binocular unmasking reflects the binocular system's ability to respond to interocular amplitude and/or phase differences in the patterns presented to the two eyes. In the second class of models, it is assumed that the left- and right-eye patterns are first summed to form a "Cyclopean" eye. In these models, detection depends on the effect this summation process has on the power spectrum of the summated patterns. To decide between these two classes of models, we observed the occurrence of binocular unmasking when (1) the contrast of masker and signal was varied identically in both eyes and (2) the contrast of masker and signal was varied in one eye only. Consistent with our previous research, we found that the results can be accounted for in terms of a linear summation model of binocular unmasking; the alternative interocular phase detection model was disproved. The implications of these findings for binocular contrast summation in the absence of visual noise are discussed.     

Binocular unmasking with unequal interocular contrast: The case for multiple Cyclopean eyes

Under certain conditions, the detection threshold for a sinusoidal grating embedded in a noisy background may be an order of magnitude lower when binocular cues are available than when monocular cues only are present. Such binocular unmasking occurs only when the degree of interocular disparity for the target differs from that of the background. Two classes of models have been advanced to account for such unmasking. The first assumes that orientation-specific, spatial frequency channels in each eye encode the amplitude and phase of the spatial frequency component of the pattern the channel is tuned to detect. Thus, a difference in interocular disparity between target and background could result in interocular amplitude and/or phase differences in left- and right-eye spatial frequency channels. When, however, there are no disparity differences between target and background, there will be no interocular differences in amplitude and phase in the left- and right-eye channels. In this model, then, binocular unmasking reflects the binocular system’s ability to respond to interocular amplitude and/or phase differences in the patterns presented to the two eyes. In the second class of models, it is assumed that the left and right-eye patterns are first summed to form a “Cyclopean” eye. In these models, detection depends on the effect this summation process has on the power spectrum of the summated patterns. To decide between these two classes of models, we observed the occurrence of binocular unmasking when (1) the contrast of masker and signal was varied identically in both eyes and (2) the contrast of masker and signal was varied in one eye only. Consistent with our previous research, we found that the results can be accounted for in terms of a linear summation model of binocular unmasking; the alternative interocular phase detection model was disproved. The implications of these findings for binocular contrast summation in the absence of visual noise are discussed.