Assimilative hue shifts in color depend on bar width

Hue shifts were measured in isoluminant color gratings whose bar width was varied from 2′ to 20′ of visual angle. Subjects matched the hues in each grating with individual Munsell swatches. Hue shifts were largest for bar widths of 2′; however, they depended on the color combination used. Green and red shifted toward (i.e., assimilated with) whatever second grating color they were paired with. Blue, on the other hand, assimilated with red and with yellow, but remained relatively unchanged when combined with green. Yellow shifted only minimally, regardless of the second grating color. Hue shifts decreased with increasing stripe width and disappeared between 4.5′ and 7.5′. Compared with the assimilative hue shifts, color contrast effects were slight or absent. These results cannot be attributed merely to chromatic aberration, macular pigment, eye movements, or field size.     

Use of the Sleep Assessment Device (Kelley and Lichstein, 1980) to validate insomniacs' self-report of sleep pattern

A comparison is presented of insomniacs' self-reported sleep pattern and objectively monitored sleep using the Sleep Assessment Device (SAD; Kelley & Lichstein, 1980). Analysis of 110 subject nights revealed modest but significant subjective overestimates of both sleep latency and sleep duration which were accounted for by the demands of the task (i.e., longer time periods are harder to estimate accurately). Correlations between self-report and SAD measures were, however, consistently high, suggesting that self-report may be a valid index of sleep disturbance. Results are discussed with reference to the clinician's task in evaluating sleep complaints.This research stury was supported by a grant from the Research Fund of Lanarkshire Health Board, Scotland.     

Sex and gender bias in self-report personality disorder inventories: item analysis of the MCMI-II, MMPI, and PDQ-R

There has been considerable controversy and research regarding sex bias in the diagnosis of personality disorders, but little has involved self-report inventories. Thus this study investigated items from the Millon Clinical Multiaxial Inventory-II (Millon, 1987), the Minnesota Multiphasic Personality Inventory (Morey, Waugh, & Blashfield, 1985), and the Personality Diagnostic Questionnaire-Revised (Hyler & Rieder, 1987). Subjects (N = 189) completed the Histrionic, Dependent, Antisocial, and Narcissistic scales from these inventories, along with the Bem Sex Role Inventory (Bem, 1974) and the Symptom Checklist-90-Revised (Derogatis, 1977). Items were considered to evidence sex or gender bias if they (a) failed to correlate with dysfunction and (b) exhibited sex or gender role differences. At least 13 items evidenced sex bias (76 items using a more liberal threshold). The majority were from Narcissistic scales; few Histrionic items evidenced sex or gender bias. Implications with respect to sex-bias assessment and item construction are discussed.     

Predictors of Recycling Behavior: An Application of a Modified Health Belief Model1

In an examination of environmentally related behavior, the health belief model (HBM) was applied to the recycling behavior of a random sample of Missouri residents. The results indicated that both the basic and modified versions of the HBM significantly predict recycling behavior; significant predictors include perceived barriers, perceived likelihood of negative outcomes due to failure to recycle, self-efficacy, and consideration of future consequences. These findings are consistent with applications of the HBM to health-related actions. The poor performance of several variables provides evidence of the psychological processes underlying decisions to recycle.     

Transfer of a response controlling stimulus duration across discrimination problems

In the acquisition phase, pigeons learned to peck at a changeover key to shorten the duration of S? but not of S+ presented on the food key in a discrimination problem. In the transfer phase, the significance of S+ and S? was changed through extinction of both, equal reinforcement, or discrimination reversal, while the changeover key was not available. Transfer tests then showed appropriate modification of the changeover response. Similar transfer was demonstrated across orthogonal stimulus dimensions. Further analytic studies showed that this transfer of the changeover response did not depend upon mediation due to differential response rates to the food key. This research strategy enriches the study of the “second learning process” by providing an indicator of stimulus control in all phases of the procedure. Direct transfer between different problems also indicates that discriminative stimuli, although physically dissimilar, have the same “psychological value” for the subject.     

Computer signal detection by monitoring auditory evoked potentials

A digital computer, using a simple decision algorithm, attempted to determine when an acoustical signal had been presented to a cat by monitoring the amplitude of the evoked potentials (EP) at brainstem auditory nuclei. The signal-to-noise level at threshold and the shape and range of the decision model “psychometric functions” were similar to those obtained from humans in the same task. In addition, the detection performance obeys Weber’s law, the mean amplitude of the EP increases monotmonically with signal level, the variance of the amplitude is independent of both signal and noise level, and both the mean latency and the variance of the latency of the peaks decrease with increasing signal level. These findings suggest that the synchronization in firing of a population of single units plays a part in determining the amplitude of the EP. Interaural effects in detection performance were found at the inferior colliculus and, to a lesser extent, at the superior olive.     

Rhythmical body movement in sleep: a brief review and treatment study

Vigorous and damaging head-banging and head and body-rocking can occur in normal subjects of average intelligence before and during sleep. Reports of behavioural treatments for this are reviewed. Data from the present case and others suggest that waking plus efficient response prevention is sufficient to substantially reduce or eliminate the activity even when the treatment has been withdrawn for up to one year. The aetiology of the activity is not understood. However, this case suggests that head- and body-rolling, when long-established, need not enhance the quality of sleep since this was unimpaired on completion of treatment and was possibly even improved by the elimination of the movements. The present case also demonstrates that the behaviour can be treated successfully even when considerable environmental stresses occur.     

Attention and multidimensional discrimination1

Observers’ ability to perform several discrimination tasks at the same time was tested using a two-alternative temporal forced-choice procedure. Discrimination of two auditory dimensions (pitch and intensity) and two visual dimensions (horizontal position and vertical position) was measured under conditions where one, two or all four dimensions required attention. Three signal durations were used: 67, 133, and 200 msec. Increasing the number of dimensions requiring attention systematically reduces the precisions of discrimination for each dimension. Auditory and visual discrimination is affected similarly. The amount of reduction in discrimination is independent of whether the dimensions requiring attention involve the same or different sensory modalities. The data are analyzed for evidence of a constant processing capacity employed in both single and multidimensional discrimination. The possibility that the observed performance levels could be achieved by sequentially processing the simultaneous inputs is also considered.