Expectancy and Intermittency

Abstract

When a human subject responds to the second of two closely succeeding stimuli, his reaction time to the second stimulus tends to increase sharply as the interstimulus interval decreases. Controversy has centred on the issue of whether this increase is mainly due to the effects of the first stimulus in producing some kind of block in the central analysing systems or whether it is mainly due to the temporal uncertainty of the second signal, as determined by the distribution of interstimulus intervals used.

By substituting for the first stimulus a spontaneous response on the part of the subject and holding the distribution of interstimulus intervals constant, it is shown that the delays in responding to the succeeding signal are eliminated, even at intervals as short as 50 millisec. This is interpreted as evidence in support of the intermittency hypothesis and as a clear indication that the increase in reaction times normally observed is not a result of the distribution of interstimulus intervals.

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References

Bertelson

Boons

J. P.

(1960). Time uncertainty and choice reaction times. Nature 187, 531–2.

Broadbent

D. E.

(1958). Perception and Communication. London.

Borger

(1963). The refractory period and serial choice reactions. Quart. J. exp. Psychol. 15, 1–12.

Davis

(1956a). The limits of the “psychological refractory period.”. Quart. J. exp. Psychol. 8, 24–38.

Davis

(1956b). Comments on “Central inhibition: some refractory observations.”. Quart. J. exp. Psychol. 8, 39.

Davis

(1957). The human operator as a single channel information system. Quart. J. exp. Psychol. 9, 119–29.

Davis

(1959). The role of “attention” in the psychological refractory period. Quart. J. exp. Psychol. 11, 211–20.

Drazin

D. H.

(1961). Effects of foreperiod, foreperiod variability, and probability of stimulus occurrence on simple reaction time. J. exp. Psychol. 62, 43–50.

Elithorn

Lawrence

(1955). Central inhibition: some refractory observations. Quart. J. exp. Psychol. 7, 116–27.

10.

Elithorn

(1961). Central intermittency: Some further observations. Quart. J. exp. Psychol. 13, 240–7.

11.

Fraisse

(1957). La période réfractaire psychologique. L'Année Psychol. 57, 315–28.

12.

Halliday

A. M.

Kerr

Elithorn

(1960). Grouping of stimuli and apparent exceptions to the psychological refractory period. Quart. J. exp. Psychol. 12, 72–89.

13.

Hick

W. E.

(1948). Discontinuous functioning of the human operator in pursuit tasks. Quart. J. exp. Psychol. 1, 36–57.

14.

Hick

W. E.

Welford

A. T.

(1956). Comments on “Central inhibition: some refractory observations.”. Quart. J. exp. Psychol. 8, 39–41.

15.

Karlin

(1959). Reaction time as a function of foreperiod duration and variability. J. exp. Psychol. 58, 185–91.

16.

Kay

Weiss

A. D.

(1961). Relationship between simple and serial reaction time. Nature 191, 790–1.

17.

Klemmer

E. T.

(1956). Time uncertainty in simple reaction time. J. exp. Psychol. 51, 179–84.

18.

Klemmer

E. T.

(1957). Simple reaction time as a function of time uncertainty. J. exp. Psychol. 54, 195–200.

19.

Welford

A. T.

(1952). The “psychological refractory period” and the tuning of high speed performance—a review and a theory. Brit. J. Psychol. 43, 2–19.

20.

Welford

A. T.

(1959). Evidence of a single channel decision mechanism limiting performance in a serial reaction task. Quart. J. exp. Psychol. 11, 193–210.