Visual search through words and nonwords in horizontal and vertical orientations.

In a repeated measurement design, 18 college women searched for target letters in 18 lists of common words, rare words, and nonwords arranged either vertically or horizontally. The mean search time in seconds for three trials in each of six conditions was expected to be significantly slower for nonwords than for words and for vertical orientations than for horizontal orientations. More importantly, a significant interaction was predicted between direction of search and the type of list searched. Results confirmed earlier findings that the two main effects were significant; the significant interaction provided empirical evidence that consideration needs to be given to both intraword redundancy and direction of visual search.     

The Rathus Assertiveness Schedule modified for early adolescents

The 30-item Rathus Assertiveness Schedule was modified for the seventh-grade population using the method of peer ratings. Split-half reliability scores are of moderate to high acceptability (N=108, 0.69<r's<0.81,P's<0.01). The method of peer rating itself attained a moderate to high split-half reliability (N=108, 0.46<r's<0.95,P's<0.01). Correlation of the Modified Rathus Assertiveness Schedule with peer ratings established validity in three of the four experimental populations (P<0.05). The results obtained from the present study are comparable to those obtained by S. A. Rathus (Behavior Therapy, 1973b,4, 398–406).The research for this article was cofunded by the National Interagency Council on Smoking and Health and the American Heart Association of Western New York.     

College women with differential linguistic-quantitative ability patterns: performance on two visual serial-search tasks

Two groups of 14 college women, equated on College Entrance Examination Board Scholastic Aptitude Test scores but showing a discrepancy of at least 150 points between the scores on the Verbal and Mathematical Aptitude Test, were compared on two visual serial-search tasks; a 2 X 2 mixed factorial design was used. There was a trend in the direction of more rapid visual serial-search by the low linguistic-high quantitative subjects than for the high linguistic-low quantitative subjects. Consonant with earlier findings, visual serial-search time was significantly faster for number targets than for letter targets. Between ability patterns and target characteristics there was no significant interaction. The need to include more complex visual serial-tracking tasks in any reexamination of the observed results was noted.     

Differentiated perceptions of exertion: part II. relationship to local and central physiological responses

Differentiated ratings of perceived exertion in the legs and chest were compared to local and central physiological adjustments during submaximal cycle ergometer exercise. 50 male subjects performed three separate cycle ergometer tests. Power output was held constant at 840 kpm/min., while pedalling rate was randomly set at 40, 60, or 80 rpm. Differentiated reports of exertion from the legs were considered to be local signals and reports from the chest to be central signals. Ratings of exertion for the legs, chest and over-all body were each significantly higher at 40 rpm than 60 or 80 rpm. Heart rate, oxygen uptake, ventilation and respiratory rate were also higher at 40 rpm. Lactic acid, pH, and pCO2 were similar between pedalling rates. Lactic acid did not operate differentially to influence local perceptual signals from the legs. Central measures of respiratory and aerobic metabolic adjustments were consistent with the more intense regional report of chest exertion at 40 rpm.     

Leaving patches: An investigation of a laboratory analogue

Five pigeons were trained on a procedure that has been used as a laboratory analogue to natural patch residence. Trials commenced with two responses available. One of these might provide a reinforcer if the patch was a prey patch; the other ended the residence time in the patch and, after a fixed travel time in blackout, produced another patch that might or might not provide a reinforcer. Patch residence also ended, and was followed by the same travel time, after a reinforcer was obtained or after a fixed maximum time was spent in the patch. The dependent variable was patch residence time, from the commencement of the patch to the time at which the subject emitted a response to exit from the patch or until the maximum patch residence time had elapsed. In Parts 1 to 3, the duration of the imposed travel time was varied from 0.25 to 16 s at three different probabilities (.05, .1, and .2) of food per second (λ) in prey patches. As reported in previous research, both increasing travel time and decreasing probabilities of reinforcers per second increased patch residence time. In Parts 4 to 7, the probability of prey trials (ρ) was varied in an irregular order from .1, through .2, .5, and .7, to .9 for different combinations of λ and travel time. Respectively, these were in Part 4, .05 per second and 0.25 s; in Part 5, .05 per second and 16 s; in Part 6, .2 per second and 0.25 s; and in Part 7, .2 per second and 16 s. A previously offered model, based on optimization assumptions, substantially and consistently underpredicted patch residence time. However, a modification of that model, which assumes that the subjects could not accurately discriminate the residence time that provided the minimum interreinforcer interval, described the data well. The same model also described previously reported residence times in a different species with a uniform distribution of prey-arrival times.     

Stimulus control and response bias in an analogue prey-detection procedure

The present study compared the performance of 6 pigeons trained to detect luminance differences in two different signal-detection procedures. Exposed to a three-key array, the pigeons were trained to peck the left key when the brighter of two light intensities had been presented on the center key and to peck the right key when the dimmer of two light intensities had been presented on the center key. Procedure A was a standard signal-detection procedure in which left/bright and right/dim responses produced food reinforcement and left/dim and right/bright responses produced periods of timeout. Procedure B was designed to simulate some of the contingencies operating in a prey-detection situation. Left-key responses produced reinforcement following the brighter center-key stimulus and a period of timeout following the dimmer center-key stimulus. Right-key responses always produced a short period of timeout irrespective of the stimulus. Within each procedure, the duration of timeout arranged for false alarms (left/dim responses) was varied between 3 s and 120 s. Measures of accuracy and response bias were compared between the two procedures. The timeout manipulation produced systematic, but relatively small, changes in these measures when right/dim responses (i.e., correct rejections) produced reinforcement (Procedure A). Arranging timeout for right/dim responses in Procedure B produced greater variability in accuracy and response bias than did arranging reinforcement, but this variability was not related to timeout duration. Overall, discrimination accuracy was considerably higher when right/dim responses produced timeout than when they resulted in reinforcement, and accuracy was accompanied by a large bias toward the response associated with reinforcement. These results are consistent with a recently proposed model of signal detection.