Accession Number : AD0721213

Title :   Variability in the Timing of Simple Motor Responses,

Corporate Author : BOLT BERANEK AND NEWMAN INC CAMBRIDGE MASS

Personal Author(s) : Nickerson,Raymond S.

Report Date : 24 JUL 1970

Pagination or Media Count : 77

Abstract : Five experiments were conducted to investigate variability in the timing of simple motor responses. The task was to make a response a specified period of time following the occurrence of a signal. Target intervals ranged from 250 msec to 8 sec in the first experiment, and from 250 msec to 2 sec in the others. Absolute variability was measured by the standard deviation and the interquartile range. Three indications of relative variability were used: the ratio of the standard deviation to the mean, the ratio of the interquartile range to the median, and the proportion of responses falling within specified regions of the time distribution. Absolute variability increased with target interval, although the difference between the results obtained with 250 and 500 msec intervals was small. Relative variability was largest with the shortest intervals used. Performance feedback, in the form of an analog display proved to be effective in decreasing variability, at least for the shortest intervals used. Also, variability was further reduced when S was allowed to initiate the interval being judged as well as to terminate it, again with the most pronounced effect being obtained with the shortest intervals. Extensive practice by one S did not reduce variability noticeably. (Author)

Descriptors :   (*MOTOR REACTIONS, TIME), REACTION(PSYCHOLOGY), PERIODIC VARIATIONS, STATISTICAL ANALYSIS

Subject Categories : Psychology
      Anatomy and Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE