Stimulus compatibility effects of an accessory visual stimulus on auditory sensitivity

Studies have reported that an accessory stimulus in a second modality can have a facilitative effect on sensory detection in a primary modality. However, performance declines when the subject has the additional task of reporting on the accessory stimulus. The facilitative effect has been attributed to an arousal or warning process, while the interference effect has been characterized as a result of limited channel capacity. Auditory sensitivity was assessed under accessory visual stimulation. Visual stimulus intensity (arousal), processing demand, and interstimulus compatibility (same or opposite direction of change of primary and secondary stimuli) were manipulated. The results indicated that interstimulus compatibility, not arousal, accounted for the obtained facilitation effect. Interference due to additional task demands was not observed. It was proposed that the facilitation effect was due to selective sensory encoding.     

Foreground and background in dynamic spatial orientation

The dependency of visually induced self-motion sensation upon the density of moving contrasts as well as upon additional stationary contrasts in the foreground or background was investigated. Using two different optokinetic stimuli, a disk rotating in the frontoparallel plane, and the projection of horizontally moving stripes onto a cylindrical screen, it was found that: (1) visually induced self-motion depends upon the density of moving contrasts randomly distributed within the visual field and, with a single contrast area of 1/4 %, is saturated when about 30% of the visual field is moving; (2) additional stationary contrasts inhibit visually induced serf-motion, proportional to their density; and (3) the location in depth of the stationary contrasts has a significant effect upon this inhibition. Their effect is considerable when located in the background of the moving stimuli but weak when appearing in the foreground. It is concluded that dynamic visual spatial orientation relies mainly on information from the seen periphery, both retinal and depth.     

Criterion adjustment and probability matching

Twenty subjects made all possible (136) pairwise-comparison judgments of pattern goodness between 17 five-dot patterns. Using multidimensional scaling and hierarchical clustering analyses, a two-dimensional representation was judged the most appropriate for the derived pattern space. The interpreted structure of the spatial-hierarchical configuration strongly supported previous findings that pattern redundancy is the most salient dimension underlying pattern goodness judgments and that patterns can be partitioned on this dimension according to the size of their equivalence sets, i.e., the number of patterns resulting from rigid rotations in 90-deg increments or reflection. A psychological mechanism that accounts for the effect of pattern redundancy on judged goodness was proposed.     

Cognitive processing and time perception

When a visual field is presented for 40 or 80 msec and a subject is asked to judge the duration of the stimulus, judged duration is found to be less when the field is blank than when the field contains three letters, but is the same whether the three letters form a word or not. The perceived difference between “filled” and “blank” fields increases when the subject is required to memorize the presented letters. These data are consistent with a theory which assumes,inter alia, that a stimulus is analyzed by a visual information processor and a timer, that attention is shared between these processors, and that temporal judgments are based on the output of both processors.     

A simple device for the preparation of exactly aligned dichotic tapes

A system is described involving three tape recorders and a control device whereby dichotic tapes can be prepared with onset alignment accurate to a few milliseconds, or to a measured asynchrony if required. No modifications of any sort are necessary for the three tape recorders. The two channels are separately recorded in the speaker’s own time, the only requirement being that the separate words be spoken with an interword interval of 350 msec or more, to provide sufficient time for starting and stopping the system. A tone burst is placed directly on tape on another channel ahead of each word, the latter being delayed by recording in tandem through two tape recorders. The first recorder is set to the delay (echo, NAB) facility, while the tone is recorded directly on the second. Subsequently, when this is done for each item on the two speech channels, the device, described below. utilizes the tone bursts to align the two input recorders. It then rerecords each pair of words on to the third (output or dichotic) machine, to the desired synchrony/asynchrony, and interitem interval. The system can be left to align the two channels automatically. A maximum repetition rate of two dichotic pairs every 1.3 sec can be achieved with Revox A77 tape recorders.     

Design considerations for an on-line computer system for automated psychiatric assessment

The computer-assisted multidisciplinary Psychiatric Assessment Unit at the Salt Lake City VA Hospital required a unique computer system. Design considerations and procedures for development of a Psychiatric Real-Time Information System for Management (PRISM) are outlined. This design is presented as an example for others considering implementing on-line systems. Advantages of the approach are discussed.     

The deceleration of inappropriate comments by a natural consequence

The characters of this study were two boys in a class for pupils with learning disabilities. The subject was a nine-year-old boy who emitted certain inappropriate comments in class. The manager throughout this study was a peer of the subject.Following a period of initial assessment, which revealed that the inappropriate verbalizations occurred about twice each day, the peer-manager, contingent on each inappropriate remark, moved away from the subject to another desk. Furthermore, before he moved, he explained to the subject why he was displeased. The peer-manager, after a period of time, returned to his original location contingent on appropriate verbalizations of the subject.This technique proved effective in that the subject rarely responded inappropriately throughout the remainder of the school term. Further, it was reported that follow-up observations taken the next year, when the pupil was in a different class, revealed that the inappropriate verbalizations had not reoccurred.     

The effects of familiarity in a perceptual matching task

Latencies of same-different judgments to pairs of two-digit numerals were recorded for stimuli presented in familiar or unfamiliar (inverted) orientation. Familiar stimuli were responded to more quickly than unfamiliar. For both stimulus types, latencies were correlated with the syllable length of the verbal representation of the numerals, allowing the interpretation that the effect of stimulus orientation is on encoding processes. In two other experiments, it was found that familiarity had no effect on different judgments when the stimuli were relatively simple (e.g., a single digit), but did affect different judgments with more complex stimuli. These results were related to the hypothesis that the complexity of verbal material determines whether different judgments are instigated by visual or by verbal representations of the stimuli.