James R. Antes

Sex and coding strategy effects on reaction time to hemispheric probes

Two experiments were conducted to investigate the influence of coding instructions on cerebral laterality differences. Experiment I required 20 subjects (10 female) to use either rehearsal or imagery coding strategies in a recognition task with word probes to the right and left hemispheres. No hemispheric differences were found, but sex of subject was found to be related to coding strategy. Ten subjects (5 female) in Experiment II performed a similar task, except picture probes were used. Subjects using rehearsal coding responded faster to left-hemisphere probes, but faster to right-hemisphere probes when imagery coding was employed. The differing laterality effects in these experiments were attributed to naming responses implicitly required in Experiment II.

Processing global information in briefly presented pictures

SummaryThe effect on object recognition of the processing of the global information in contextually coherent scenes was investigated in two experiments. In Experiment 1 subjects saw 100 ms presentations of line drawings containing objects that were either usual or unusual given the picture context. Following each exposure they were required to select from among four objects the one that had been contained in the scene. The consistency of the three distractor alternatives with the meaning of the picture was varied. Recognition accuracy was poor for unusual objects and when the distractors were consistent with the picture meaning and did not substantially differ from the performance of subjects who selected response alternatives after being provided with a theme of the picture, without actually viewing the pictures. This supports the conclusion that subjects were responding on the basis of the global information but not the local object information in the pictures. When the exposure duration was increased to 2 s (Experiment 2), processing of local information was apparent for both usual and unusual objects but effects of the global information were still evident.

Gobal-local precedence in picture processing

SummaryPrevious investigations of the global precedence hypothesis (Navon, 1977) have utilized compound letter stimuli. In these stimuli there is no predictive relationship between the global and local levels. Pictorial stimuli, however, contain mutually predictable global and local levels. This study investigated the global precedence hypothesis with pictorial stimuli using a Stroop-like interference task similar to that used by Navon. Subjects were required to respond either to the global (e.g., beach or farm) or local (e.g., boat or tractor) level of a scene. The display size and consistency of the global and local levels were varied. Response latencies supported global precedence for small scenes (4°) but local precedence for large scenes (16°). The results are interpreted by a model in which the priority of processing is determined by a critical spatial frequency sampling bandwidth.

Visual attention and depression : cognitive biases in the eye fixations of the dysphoric and the nondepressed

The eye fixations of 20 dysphoric and 20 nondepressed subjects were recorded as the viewed a series of pictures with both happy and sad regions in order to test the hypothesis that dysphoric subjects would tend to fixate sad themes and that nondepressed subjects would tend to fixate happy themes. It was found that both the dysphoric and the nondepressed fixated happy regions significantly more often, longer, and sooner than they fixated sad regions. It was also found that the dysphoric fixated sad regions significantly more often than did the nondepressed. These results were interpreted as reflecting the operation of a visual attentional defense mechanism, which may work less effectively for the depressed, whose function may be to help the individual avert depression by avoiding negative themes and focusing on positive themes. The impact of negative cognitive biases in this study appeared to be to mitigate the strength of an overall more powerful positive cognitive bias.

The nature of processing early in picture perception

SummaryThe present study investigated the availability of information related to object identity and scene context during the initial stages of picture perception. Pictures were presented for 10, 30, 50, 75, 100, 150, 300, or 1000 ms and subjects were asked to determine if a probe was the portion of the scene which had appeared in that location. The probed sections had previously been rated on informativeness and high-, medium-, and low-rated areas were examined. Medium-informative sections were recognized better than high- or low-informative sections. A comparison of sections in the central and peripheral positions of the visual field indicated that medium-informative sections were recognized better in the periphery, while highly informative areas were recognized more accurately at central locations. These results are interpreted as supporting the concept that context develops prior to the identification of objects.

Hydrocortisone reduces auditory sensitivity at high tonal frequencies in adult males

The present study was designed to investigate the effects of treatment with cortisol on auditory tonal detection. College males were given either 20 mg of hydrocortisone or a placebo (dextrose) in a double blind design. Thereafter, thresholds were determined for frequencies of 500, 1,000 and 4,000 Hz using the method of limits. These results were then converted to change scores by using thresholds obtained for the same subjects at the same frequencies prior to treatment. Planned comparisons indicated that treatment with cortisol reduced sensitivity at 4,000 Hz but had no effects at other frequencies. Also, an overall analysis of variance indicated greater right ear improvement and greater improvement at lower frequencies. These findings are explained as resulting from the ability of glucocorticoids to alter cellular metabolism or reduce levels of adrenocorticotropic hormone.

Discriminating artists from nonartists by their eye-fixation patterns

Discriminant analysis was used to differentiate 15 artists from 15 nonartists on the basis of their eye-fixation patterns. Contributing significantly to the discriminant function were fixation densities on the less important aspects of familiar and unfamiliar paintings.

The Effect of a New City Traffic Route on the Cognitive Maps of Its Residents

This study addressed the question of how changes In travel paths through a city occasioned by the construction of a new connecting street, Influenced the cognitive maps of the citys residents. Grand Forks, North Dakota recently constructed an overpass over a railroad switching yard that bisects much of the city. Residents were asked to judge the distances between selected points In the city on two occasions, once before the overpass was completed and again six months later. Female residents showed Improved performance, especially In the areas of the city connected by the overpass, while male distance estimates did not change. It was suggested that the females made their judgments based upon Inferences from travel paths while males approached the task In a more spatlal manner, using a mental representation of the city.

Recognizing and localizing features in brief picture presentations.

In two experiments, subjects saw a series of brief picture flashes, each followed by a 10-sec presentation of a small picture section. In Experiment 1, subjects were required to decide if the section had been part of the 100-msec picture presentation. Experiment 2 had 100-msec and 500-msec presentations, and the task was to indicate the location of the section in the picture. Both recognition and localization accuracy depended upon the rated informativeness of the probed section and the section’s location with respect to point of focus. Performance on the recognition task was superior to that on the localization task, suggesting different rates of acquisition of identity and location information. The results were interpreted in terms of a model of picture perception based upon two kinds of processing: identification of individual objects and a holistic characterization of the scene. The results also have implications regarding the use of information in the guidance of initial eye fixations.

Effects of capacity demands on picture viewing

Effects of cognitive-resource demands on picture-viewing patterns were investigated. The eye fixations of 72 subjects were recorded as the subjects viewed pictures and concurrently performed one of three listening tasks. Half of the subjects were asked to remember certain objects from the pictures and half had no-memory instructions. Concurrent auditory monitoring increased interfixation distances and the frequency of fixations on regions of high informativeness, and decreased the area of the pictures explored and the memory for objects in the scenes. it is suggested that the demands on cognitive resources influenced subjects’ ability to encode and integrate fixated information and therefore prolonged the normal first phase of viewing, described by Buswell (1935).