Significant Increase In Reaction Time Research Articles

Performance on a reciprocal tapping task with variations in intertapping interval.

Fitts' law was investigated in a study of the effect of the index of difficulty (ID) and intertapping interval upon reaction time (RT) and movement time (MT) for a reciprocal tapping task. ID showed its well-established relationship with MT as described by Fitts' law: MT = aID + b. Improvement in the linearity of this relationship was, however, demonstrated by expressing MT in logarithmic units. While ID had an unsubstantial (though significant) effect on RT, increases in intertapping interval from zero to any level of discrete tapping led to significant increases in RT of about 135 msec. The results are interpreted as lending support to Fitts' thesis that RT and MT reflect independent phases of information processing.

Scanning memory for multidimensional stimuli with extended practice

Memory load and the similarity between positive and negative sets were varied orthogonally in an information-reduction task which required S to respond either “yes” or “no” to the question of whether or not a visually displayed two-dimensional pattern had been contained in a previously memorized set of patterns. Six Sa were given 8 days of practice. The results showed that throughout practice, there was a significant increase in reaction time with increaaes in the similarity of positive and neptive sets. The memory load differences sipificantly decreaaed to zero with practice, and this drop was independent of the similarity effect.. It was concluded that extended practice influences memory load differences and effects that reflect the complexity of the memory comparison process differentially.

The effects of hypoxia on choice reaction time and movement time.

An investigation was made of the effects on choice reaction time and movement time of hypoxia (oxygen deprivation) induced by a reduction in total air pressure inside a decompression chamber. The subjects were adult humans who were given no pre training on the task used, were tested once at a pressure level equivalent to some altitude between ground level and 15,000 ft, and were given no information on the altitude attained. A variety of tasks were used with simple and complex spatial and code relationships between stimulus and response. In three experiments on 92 subjects in all the most consistent finding was that from gTOund level to 7,000 ft or 10,000 ft there was a significant increase in reaction time and a significant decrease in movement time. Above 10,000 ft the results were less consistent, reaction time showing further increase or a decrease to that found at ground level and movement times varying in the opposite direction to these changes. It was suggested that in young adult subjects and in tasks of low ‘ mental load ’ the inverse variation of reaction time and movement time was quite consistent and was possibly a result of an unimpaired total response time plus a selective impairment of the time taken to initiate a response found only at intermediate altitudes. In tasks with mora ’ mental work ’ involved, hypoxic impairment of total response time was found at altitudes as low as 5,000 ft. Above 10,000 ft there was little further impairment, possibly as a result of some compensatory adjustment in drive or arousal level which might also have been the reason for the lack of impairment of reaction time at the highest altitudes in the simple tasks. The great discrepancy between these results and previous literature, and the additional finding of quicker response times with prolonged exposure to the experimental conditions, were attributed to the separate analysis of reaction time and movement time and the use of naive subjects in a novel experimental design,

EFFECT OF THREE KINDS OF KNOWLEDGE-OF-RESULTS INFORMATION ON THREE MEASURES OF VIGILANCE PERFORMANCE.

Tea Ss in each of 8 groups individually performed a watchkeeping task of 1 hr. duration. Each group was presented one of the 8 factorial combinations of the presence (or absence) of 3 different kinds of knowledge of results (KR), i.e., KR regarding missed signals, correctly detected signals, and false responses. The results indicated that KR regarding missed signals produced a significant decrease in the total number of false responses, and that KR regarding correct detections produced a significant decrease in the proportion of missed signals. When KR regarding false responses was given, there was both a significant increase in reaction time to correct detections and a significant decrease in the number of false responses. In short, the effect of providing a specific type of information in a watchkeeping task appears to be specific to the measure of performance efficiency employed. A discussion is included of the interpretation of these results.

Experimental Finger Dyspraxia

Subjects were required to perform discrete finger movements in accordance with a pre-arranged sequence of instructions. In all cases, any movement made by any finger was recorded by means of a constant-speed kymograph equipped with levers designed to record separately the movements of the individual fingers. This experiment was carried out under three conditions: (a) with no vision of the hand; (b) with direct vision of the hand; and (c) with the hand presented in mirror-image. It was found that, whereas deprivation of visual control was without effect on the efficiency of finger movements, presentation of the hand in mirror-image gave rise to significant increases in reaction time of three fingers and to an increase in the percentages of prior and substitute movements of other digits. Phenomena akin to depersonalisation were reported in some cases. It was also found that the rank order of mean reaction times of the five digits was approximately constant under all conditions and that the two fingers with the shortest reaction times were preceded by the fewest movements of other digits. These two digits were also the most frequently moved in advance when movements of other digits were requested and it is suggested that they have a certain “signpost function” in guiding identification of the remaining fingers. Some implications of these results for an understanding of “finger agnosia” are briefly indicated in an Appendix.