Sensory and motor impairment in the nerve compression block

Recently nerve compression block as a method of investigating movement control without kinaesthetic feedback has been questioned on the grounds that motor impairment (as measured by nerve conduction parameters) is a confounding factor. In order to clarify the relationship between sensory and motor function, behavioural data was obtained on both at systematic time intervals throughout the duration of the block. The findings indicated that significant decrements in tapping measures occurred somewhat earlier in the time course of the block than decreases in kinaesthetic discrimination. Also, contrary to assumption, the majority of subjects ceased to perform prior to total kinaesthetic loss. The data suggest that motor impairment is a “crucial” issue (Laszlo, 1966) in the use of this technique, and provide further behavioural support for the neurological findings of Kelso, Stelmach and Wanamaker (1974).     

The effects of intensity and interval rhythms on the perception of auditory and visual temporal patterns

Repeating temporal patterns were presented in the auditory and visual modalities so that: (a) all elements were of equal intensity and were equally spaced in time (uniform presentation); (b) the intensity of one element was increased (accent presentation); or (c) the interval between two elements was increased (pause presentation). Intensity and interval patterning serve to segment the element sequence into repeating patterns.

For uniform presentation, pattern organization was by pattern structure, with auditory identification being faster. For pause presentation, organization was by the pauses; both auditory and visual identification were twice as fast as for uniform presentation. For auditory accent presentation, organization was by pattern structure and identification was slower than for uniform presentation. In contrast, the organization of visual accent presentation was by accents and identification was faster than for uniform presentation. These results suggest that complex stimuli, in which elements are patterned along more than one sensory dimension, are perceptually unique and therefore their identification rests on the nature of each modality.     

The free-operant partial reinforcement effect: A discrimination analysis

Twelve continuously reinforced rats were extinguished in a modified operant chamber, with an S^D for goal-approach after each bar-press. Three groups of twelve rats each trained under FR 10 were extinguished with the S^D for goal-approach after every 6, 10, or 14-bar-presses, respectively. Results showed: (1) number of bar-presses to extinction was a direct function of the bar-press to S^D ratio during extinction, (2) number of food or goal-approaches was independent of both training and extinction conditions, and (3) prior to the breakdown in discrimination a revised response-unit hypothesis, based on a discrimination analysis of the effect of intermittent reinforcement, accurately predicted the number of bar-presses for each FR group.     

A test of expectancy theory in a field setting using female clerical employees

Female clerical workers were rated on seven dimensions of job performance using behaviorally based rating scales, these 266 subjects responded to questionnaire items concerned with their expectations dealing with (1) whether their job effort resulted in effective performance (Expectancy I), and (2) whether job performance leads to reward outcomes (Expectancy II). These Expectancies were found not to be highly related to the measures of job performance in contrast to expectancy theory predictions. Satisfaction with reward outcomes was found to be differentially related to individuals' expectations that performance results in the attainment of particular outcomes.     

A note on a paper by Rumelhart and Greeno

The parameters of the models described by Rumelhart and Greeno in this journal (1971) are constrained in certain ways. Neglect of this fact in their paper leads them to an inadmissible set of parameter values, and an invalid argument and statement concerning the equivalence of two models. However, their conclusion that the Restle model fits their data better than the Luce model remains unchanged.     

On-line monitoring of eye-position signals in contingent and noncontingent paradigms

This paper presents a research methodology for the study of human attentional and perceptual processes by means of on-line monitoring of eye-position signals. The first part of the presentation considers techniques by which commercially available apparatus may be interfaced to a minicomputer for purposes of monitoring eye-position signals during psychological experiments. Hardware and software techniques related to automating the calibration, recording, and analysis of eye-position data are discussed. The second part of the paper discusses a more advanced research methodology, one in which visual stimuli are contingent upon momentary eye-position signals. The methodology is appropriate to a variety of studies in which eye movements are considered to be part of an attentional control system. Several experimental applications are described. The implementation of eye-position-stimulus contingencies on a small computer poses additional technical problems, several of which are discussed.     

Modeling strategy shifts in a problem-solving task

A computer simulation model was fitted to human laboratory data for the Missionaries and Cannibals task to explain (1) the effects upon problem performance of giving a hint, and (2) the effects of solving the problem a second time after one successful solution had been achieved. Most of the variance in the relative frequencies of different moves can be explained by positing that the effect of the hint, or of previous experience in solving the problem, is to cause subjects to switch more promptly from a strategy of balancing the numbers of missionaries and cannibals on both sides of the river, to a means-ends strategy.     

REDUCING TIME LIMITS: A MEANS TO INCREASE BEHAVIOR OF RETARDATES1

A common assumption in special education is that temporal limits for a task should be expanded so that ample time is provided for completing the work. This study describes the opposite strategy of restricting temporal limits to augment academic performance. Three educable retarded children received token reinforcement contingent on the number of correct math problems answered during daily sessions. A reversal design was used to assess the effects of an abrupt reduction in time limits (20-5-20 min) and a graduated sequence of reductions (20-15-10-5-20 min). The graduated sequence resulted in rate increases of correct responding ranging from 125% to 266% and these gains endured when temporal limits were again expanded. In contrast, the abrupt shift produced interfering emotional behaviors and rate decreases in academic performance of 25% to 80%. The findings indicate that systematically restricting temporal limits for an academic task can further enhance the performance of slow learners already maintained by a token system.