Stabilized images: Dependent variable specificity of pattern-specific effects with prolonged viewing

Two studies report results of viewing lines in different orientations in stabilized Maxwellian view. The first study examined the time course of four dependent variables-whole- and partial-fade frequencies and whole- and partial-fade durations. Whole-fade frequencies increased systematically throughout 10 min of the 15-min viewing session and were sensitive to line orientations. Partial-fade frequencies increased for 3–5 min during which orientation specificity occurred. Thereafter, partial-fade rate was constant and pattern-specific effects disappeared. Mean fade duration, which increased throughout the 15-min session for whole fades but for only 5 min for partial fades, was not pattern-specific. The second study demonstrated that the pattern specificity of whole fades could not be accounted for in terms of time-dependent extraneous variables. It was concluded that partial and whole fades may reflect the operation of different visual processes. The complete fading of images was attributed to the operation of supraretinal pattern processing units.     

Event-related potential studies of cerebral specialization during reading: I. Studies of normal adults

A number of methodological features were incorporated in a paradigm designed to maximize the likelihood of finding reliable event-related potential (ERP) signs of functional specializations between and within the cerebral hemispheres. Every subject was more accurate in identifying words presented to the right than to the left visual field. The morphology of the ERPs elicited by these words varied considerably as a function of electrode position both within and between the hemispheres. Amplitude asymmetries of ERP components recorded from occipital regions of the two hemispheres varied systematically with the position of the word in the visual field. On the other hand, ERPs from more anterior (temporal and frontal) regions displayed large asymmetries which were in the same direction regardless of the visual field of word presentation. The most prominent such asymmetry was in the negativity in the region 300–500 msec (N410) which was larger in the left than the right hemisphere in every subject. These results demonstrate that in this paradigm which demands specialized language processing ERPs are sensitive to aspects of cerebral organization both within and between the two hemispheres.     

Persuasion,surveillance, and voting behavior

More than 4000 students received one of three letters urging them to vote in a campus primary election. Two letters suggesting that voting behavior would be monitored produced 37% turnout compared with 32% for a nonsurveillance letter and 26% for noletter controls. Differences among these three groups are significant at p < .01. The letters also increased turnout in a runoff election held one week after the primary; however there were no differences among the three letters. These results are discussed in terms of Thibaut and Kelley's three-step process for enforcing group norms.     

Effects of group contingent events upon classroom noise

The first study investigated a group control procedure for suppression of excessive sound-intensity levels in a regular public school classroom. Reinforcement consisted of a 2-min addition to the class gym period and a 2-min break after maintenance of an unbroken 10-min quiet period as monitored on a decibel meter. Transgressions of the sound limit (42 decibels) resulted in a delay of reinforcement by the resetting of the timer to the full 10-min interval. The results indicated that these procedures were highly effective in suppression and control of sound intensities. The second experiment utilized a similar procedure coupled with a procedure of eliminating out-of-seat behavior. Experiment III studied the effects of Exp. II procedures on a single student's out-of-seat behavior rate. All procedures were found effective.     

Motivational control of motor performance by goal setting in a dual-task situation

Summary The goal-setting approach to task motivation is applied to examine the way in which subjects control their performance on two concurrently performed tasks under the guidance of different goals in a dual-task situation. The tasks were a simple auditory-manual reaction time (RT) task and a visual-manual pursuit-tracking task. The goal conditions assigned alternatively to the tasks differed with respect to goal specificity and feedback information (KR) given after the trials. It is shown that the improvement of performance in the task with hard, specific goals is achieved in both cases at the cost of the concurrently performed other task which, on the basis of a lack of feedback and a rather unspecific goal instruction, should have a lower priority. The data reveal some strategies hidden behind these overall changes of the average performance at both tasks. For the RT task, the adjustment to the different goals is mainly achieved by changes in the temporal control or preparatory processes as can be inferred from the RT distributions as well as from the analysis of some typical errors. For the tracking task, changes in the tracking accuracy within the overlapping RT intervals are the best indicators for the performance control under the different goal conditions.This research was supported by a grant from the Deutsche Forschungsgemeinschaft (Kl 408/4-2)