Binocular unmasking with vertical disparity

We recently found (Schneider, Moraglia, & Jepson, 1989) that the contrast threshold for the detection of a visual signal in a noisy background can be considerably lower when binocular cues are available then when monocular cues only are present. Here, we investigated the occurrence of binocular unmasking with vertical interocular disparities. Subjects reported about the presence of Gabor signals in fields of two-dimensional broadband Gaussian noise surrounded by a frame of uniform noise. They saw these stimuli through a stereoscope; in all cases, the right-eye noise field was vertically displaced relative to the left one in either an upward or a downward direction, by up to 67.6'. In one condition, the right-eye signal was displaced by an amount equal to that of the noise, so that no opportunities for binocular unmasking existed; in the other, it appeared in exactly corresponding locations in the two fields--here, binocular disparities could be used to unmask the signal. Enhanced signal detectability, by up to 12.7 dB, was observed in the latter case for both directions of displacement, but only for displacements of 13.52' and only when the signal's orientation was horizontal. We argue that these effects result from the summation of monocular inputs carried out by linear binocular mechanisms.     

FUNCTIONAL ASSESSMENT,CURRICULAR REVISION,AND SEVERE BEHAVIOR PROBLEMS

An adolescent female with multiple handicaps and a long history of severely disruptive behavior participated in a functional assessment linked directly to specific revisions in her school curriculum. During Phase 1, reversal designs were used to test hypotheses pertaining to antecedent and auricular influences on problem behavior. During Phase 2, a multiple baseline across afternoon and morning time periods demonstrated that the auricular revisions were effective in eliminating severely disruptive behavior and increasing on-task responding. Data also showed that inappropriate “psychotic” speech was reduced and appropriate social interactions were increased. Follow-up results showed that the changes were maintained throughout the school year. Questionnaire data provided social validation of the procedures and outcomes. The findings are discussed in relation to their implications for functional assessment, individualized curricula, and positive programming for students with disabilities and serious behavior problems.     

Factor influencing suicide intent in gay and bisexual suicide ideators: differing models for men with and without human immunodeficiency virus.

Of 778 gay and bisexual men (none with acquired immunodeficiency syndrome [AIDS]), 27% (n = 212) reported suicidal ideation over the previous 6 months. Covariance structure models were used to explore predictors of suicide intent among (n = 112) suicide ideators with (n = 100) and without (n = 112) human immunodeficiency virus (HIV). Current AIDS-related stressors (deaths and illnesses and perceived AIDS risk) and past levels of adaptive functioning (social isolation and depression) were significantly more powerful predictors of suicide intent among HIV-positive than among HIV-negative ideators. Biological AIDS risk predicted neither suicide intent, current distress, nor perceived AIDS risk. Pathways to suicide intent appear to be psychologically, rather than biologically, mediated. Among HIV-positive ideators, AIDS-related death and illness events predicted suicide intent but not current distress symptoms. Some suicidal ideation in response to AIDS-related events may be an effort to cope rather than a manifestation of psychological distress.     

Dynamic role of social support in the link between chronic stress and psychological distress.

How a chronic environmental stressor can interfere with the buffering effects of social support by eroding social support was analyzed in this prospective, longitudinal study. A classic buffering effect of support was found after 2 months of exposure to the stressor, household crowding. Crowded residents with low perceived support had greater increases in psychological distress than did crowded residents with high perceived support. However, after 8 months exposure the buffering effect disappeared. Moreover, greater crowding had become directly associated with lower support, which in turn was associated with greater increases in psychological distress. All analyses controlled for prior distress. Under some types of chronic stress, the buffering effects of social support may be short-lived because the stressor eventually erodes social support.     

Research on the clinical usefulness of the Rorschach: 2. The assessment of cerebral dysfunction

A review of research on the use of the Rorschach in the assessment of cerebral dysfunction indicated that the Rorschachs of patients with cerebral dysfunction do not manifest any characteristic response in terms of percentages, ratios, or any unique response to any one of the stimulus determinants of the blots (color, shading, the stimulus for movement). The patient with cerebral dysfunction does manifest a unique style of thinking; responses tend to be concrete, perseverative, and stereotypic. This finding is similar to that found with schizophrenics where research, summarized by Frank in 1990, also indicated no uniquely 'objective' response style but reflected a unique cognitive style. These two reviews taken together suggest that the better way to use Rorschach data in clinical work is as an opportunity to assess patients' thinking as opposed to the Rorschach being used as a psychometric device, yielding 'numbers.'     

Developmental perspectives on the localization and detection of auditory signals

Responsiveness of 1-, 3-, and 5-year-old children and adults to octave-band noises at .4 and 10 kHz was assessed with a go/no-go version of visual reinforcement audiometry (VRA) (Moore, Thompson, & Thompson, 1975) and a two-alternative, forced-choice version (Suzuki & Ogiba, 1961; Trehub, Schneider, & Endman, 1980). Infants performed better on the two-alternative, forced-choice version in quiet and in noisy backgrounds, and adults performed better on the two-alternative, forced-choice version in quiet but not in noisy backgrounds. Performance on the two tasks was essentially equivalent for 3- and 5-year-old children. Superior performance on two-alternative VRA over go/no-go may be due to lesser cognitive demands in the case of infants and to the engagement of superior decision strategies in the case of adults.     

Spatial and conjoint models based on pairwise comparisons of dissimilarities and combined effects: Complete and incomplete designs

In pairwise multidimensional scaling, a spatial representation for a set of objects is determined from comparisons of the dissimilarity of any two objects drawn from the set to the dissimilarity of other pairs of objects drawn from that set. In pairwise conjoint scaling, comparisons among the joint effects produced by pairs of objects, where the objects in a pair are drawn from separate sets, are used to determine numerical representations for the objects in each set. Monte Carlo simulations of both pairwise dissimilarities and pairwise conjoint effects show that Johnson's algorithm can provide good metric recovery in the presence of high levels of error even when only a small percentage of the complete set of pairwise comparisons are tested.     

Polysemy and the acquisition of the cognitive internal state lexicon

Previous research (Hall, Scholnick, & Hughes, 1987) suggested that cognitive word meanings denote six increasingly abstract and complex cognitive processes. In this paper, we further investigated two interrelated aspects of this framework. A set of 36 conversations with children aged 4:5 to 5 provided the data. In Study 1, issues related to the optimal ordering of levels were examined by comparing the original sequence with a restructured model. In Study 2, the hypothesis that, in addition toknow, other polysemous cognitive internal state words would be hierarchically organized was tested. The findings lent support to the restructured model, but rejected the hypothesis that polysemous words within the domain were characterized by equivalent,hhierarchically organized levels. We conclude by proposing that cognitive internal state words were related by complementarity of levels rather than equivalence.The research on which this paper is based was supported by a grant from the Carnegie Corporation of New York to William S. Hall. Data analysis was supported by the Computer Science Center at the University of Maryland, College Park.     

A developmental study of the relationship between geometry and kinematics in drawing movements.

Trajectory and kinematics of drawing movements are mutually constrained by functional relationships that reduce the degrees of freedom of the hand-arm system. Previous investigations of these relationships are extended here by considering their development in children between 5 and 12 years of age. Performances in a simple motor task--the continuous tracing of elliptic trajectories--demonstrate that both the phenomenon of isochrony (increase of the average movement velocity with the linear extent of the trajectory) and the so-called two-thirds power law (relation between tangential velocity and curvature) are qualitatively present already at the age of 5. The quantitative aspects of these regularities evolve with age, however, and steady-state adult performance is not attained even by the oldest children. The power-law formalism developed in previous reports is generalized to encompass these developmental aspects of the control of movement.     

Fluid noncompliance and symptomatology in end-stage renal disease: cognitive and emotional variables

Fluid noncompliance in patients with end-stage renal disease (ESRD) is a widespread problem with severe consequences for health. In addition, ESRD patients report considerable stress in relation to their illness and dialysis treatment. The present study examined the role of cognitive and emotional variables in fluid noncompliance, symptomatology, and stress. Fifty hemodialysis patients were assessed (a) on the cognitive variables of locus of control, self-evaluations of their past compliance, and self-efficacy to resist fluid intake and (b) on the emotional variables of depression, anger, and anxiety. Results showed that cognitive variables accounted for fluid noncompliance and predicted future adherence. Patients high in negative emotions complied equally as well as patients low in negative emotions but were found to report substantially more symptomatology and distress associated with their treatment. The implications of these findings for treatment of ESRD patients and future research are discussed.