Stereoscopic depth and the occlusion illusion

In the occlusion illusion, the visible portion of a partly occluded object appears larger than a physically identical nonoccluded region. Stereoscopic displays allowed for a direct test of the apparent-distance hypothesis. In Experiments 1A and 1B, we measured both the perceived size and the perceived depth of partly occluded targets when the binocular disparity of both targets and occluders was varied. Stereoscopic occlusion greatly increased perceived target size but not perceived target distance. A reduced illusion was still present when the target was stereoscopically in front of the abutting rectangle, however. Experiments 2A and 2B showed similar results, even when the occluding figures were illusory rectangles that formed no explicit T-junctions. Experiment 3 showed that an unexpected negative size illusion on control trials was primarily due to adaptation to the occlusion illusion on other trials. The present findings eliminate apparent-distance explanations of the occlusion illusion but are consistent with other hypotheses, such as partial modal completion and selective dimensional expansion.     

What Do We Know About Neuropsychological Aspects Of Schizophrenia?

Application of a neuropsychological perspective to the study of schizophrenia has established a number of important facts about this disorder. Some of the key findings from the existing literature are that, while neurocognitive impairment is present in most, if not all, persons with schizophrenia, there is both substantial interpatient heterogeneity and remarkable within-patient stability of cognitive function over the long-term course of the illness. Such findings have contributed to the firm establishment of neurobiologic models of schizophrenia, and thereby help to reduce the social stigma that was sometimes associated with purely psychogenic models popular during parts of the 20th century. Neuropsychological studies in recent decades have established the primacy of cognitive functions over psychopathologic symptoms as determinants of functional capacity and independence in everyday functioning. Although the cognitive benefits of both conventional and even second generation antipsychotic medications appear marginal at best, recognition of the primacy of cognitive deficits as determinants of functional disability in schizophrenia has catalyzed recent efforts to develop targeted treatments for the cognitive deficits of this disorder. Despite these accomplishments, however, some issues remain to be resolved. Efforts to firmly establish the specific neurocognitive/neuropathologic systems responsible for schizophrenia remain elusive, as do efforts to definitively demonstrate the specific cognitive deficits underlying specific forms of functional impairment. Further progress may be fostered by recent initiatives to integrate neuropsychological studies with experimental neuroscience, perhaps leading to measures of deficits in cognitive processes more clearly associated with specific, identifiable brain systems.     

Suppression effects on musical and verbal memory

Three experiments contrasted the effects of articulatory suppression on recognition memory for musical and verbal sequences. In Experiment 1, a standard/comparison task was employed, with digit or note sequences presented visually or auditorily while participants remained silent or produced intermittent verbal suppression (saying "the") or musical suppression (singing "la"). Both suppression types decreased performance by equivalent amounts, as compared with no suppression. Recognition accuracy was lower during suppression for visually presented digits than during that for auditorily presented digits (consistent with phonological loop predictions), whereas accuracy was equivalent for visually presented notes and auditory tones. When visual interference filled the retention interval in Experiment 2, performance with visually presented notes but not digits was impaired. Experiment 3 forced participants to translate visually presented music sequences by presenting comparison sequences auditorily. Suppression effects for visually presented music resembled those for digits only when the recognition task required sensory translation of cues.     

The Collective Preference for Shared Information

Decision-making groups prefer to discuss shared information that all members know instead of unshared information that a single member knows. This bias toward discussing shared information can lead groups to make suboptimal decisions when unshared information is critical for good decision making. This preference for discussing shared information may stem from group members' positive evaluations of each other's task capabilities when shared information is communicated. Members who already are perceived as capable (i.e., those high in status, experts, and leaders) need not bolster their image by communicating shared information. Instead, they discuss unshared information more than members perceived as less capable. As members low in status gain respect by communicating shared information, they may risk mentioning unshared information later during discussion. Assigning group leaders, informing members of their expert roles, and allowing ample time for discussion may increase groups' discussion of unshared information.     

Validation of a clerical test using work samples

zWork simulation performance tests of filing and proofreading were the principal criteria in a validation study of a paper and pencil clerical selection test constructed by content-oriented methods; supervisory ratings were also used. Experiment 1 was a concurrent study using as subjects 59 provisional employees. Experiment 2 was a predictive study using as subjects 184 employees actually selected on the basis of test scores. In both studies, substantial correlations were found between scores on the selection test and performance on the work samples: Estimates of correlations in the original selection group ranged from .4 to .8. Correlations between the selection test and the supervisor ratings were significant in Experiment 1, but not in Experiment 2; even when significant, they were much lower than the correlations with the work samples. These results suggest the value of using work samples as criteria for validation studies. Implications for other validation efforts are considered.     

Infant crying: Acoustics,perception and communication

This paper first reviews briefly the literature on the acoustics of infant cry sounds and then presents two empirical studies on the perception of cry and noncry sounds in their social-communicative context. Acoustic analysis of cry sounds has undergone dramatic changes in the last 35 years, including the introduction of more than a hundred different acoustic measures. The study of cry acoustics, however, remains largely focused on neonates who have various medical problems or are at risk for developmental delays. Relatively little is known about how cry sounds and cry perception change developmentally, or about how they compare with noncry sounds. The data presented here support the notion that both auditory and visual information are important in caregivers' interpretations of infant sounds in naturalistic contexts. When only auditory information is available (Study 1), cry sounds become generally more recognizable from 3 to 12 months of age; perception of noncry sounds, however, generally does not change over age. When auditory and visual information contradict each other (Study 2), adults tend to perform at chance levels, with a few interesting exceptions. It is suggested that broadening studies of acoustic analysis and perception to include both cry and noncry sounds should increase our understanding of the development of communication in infancy. Finally, we suggest that examining the cry in its developmental context holds great possibility for delineating the factors that underlie adults' responses to crying.