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Habituation of the electrodermal response as a function of stimulus similarity
Acta Psychologica 41 (1977) 415-417 0 North-Holland Publishing Company
SHORT REPORT HABITUATION OF THE ELECTRODERMAL FUNCTION OF STIMULUS SIMlLARITY
J. G. O’GORMAN
Srptembcr
AS A
and B. CRASSINI
Dept. of Pswzhology, University of‘~Vew England, Armidale, of‘Psycholog_v, l2niversit.v of Queensland, Australia
Received
RESPONSE
,Y.S. IV., Australia,
and Dept.
1976
Lists of nonsense syllables varyin g in inter-Item similarity were presented visually to independent groups of female Ss (II = 9) while the electrodermat response was monitored. (;roups in which inter-item similarity was low showed a significantly higher freqtiency of responding throughout the series, F(2. 74) = 12.08, p < 0.0 1. and a significantly larger mean response to the final stimulus in the series, F(_,? 14) = X.84. p < 0.01. The results were interpreted as support for Sokolov’s theory of stimulus coding in habituation.
Studies of the stimulus properties determining habituation of human autonomic responses have been mainly concerned with physical features of the stimulus such as intensity, duration, and interstlmulus interval (Graham 1973). Few studies have examined the importance of qualitative aspects of the stimulus. Berlyne et al. (1963) and Spinks and Saddle (1976) have shown, however, that habituation of the electrodermal response (EDR) is more rapid with simple rather than complex visual stimuli. The present study was undertaken to explore a further quahtative aspect of the stimulus. its similarity‘to other stimuli used to produce habituation. Similarity was mampulated in terms of the duplication of elements in lists of WC trigrams and habituation of EDR was examined.
416
f. C. O’Gorman, 8. CrassinilHabituation
of EDR
Method Twenty-seven female student volunteers within the age range of 17 to 25 years were randomly assigned to one of three treatment groups. From the list supplied by Runquist (1966), 16 CVC trigrams, low in both association value and meanmgfulness, were chosen. They were selected to constitute three series, one of low inter-item similarity (HUJ, QIY, GAQ, WIJ, ZIH, CIJ, KUQ. XOC), one of medium inter-item similarity (XAW, XAB, XIQ, XAK, XIN, XEV, XEP, XOC), and one of high inter-item similarity (XOC repeated eight times). Photographic slides containin g, these syllables in upper-case type were presented to the S using a Kodak carousel projector. Blank slides were interposed between stimulus slides so that projected light was not present during the inter-stimulus interval. A pre-programmed tape driven by the deck of a Sony tape-recorder controlled the interstimulus interval which varied randomly from 15 to 25 sec. Exposure duration of each slide, 2 set, was controlled by a timer which also activated the event marker on an E & M Physiograph 6 used for measurement of EDR. Silver silver-chloride electrodes and a saline jelly electrolyte were used to record EDR from the palmar surface of the middle finger of the left hand and the left wrist. The S reclined on a dental couch 1.8 m in front of the projection screen. The projector and Physiograph were housed in a room adjacent to the experimental room. The S was told that slides containing nonsense syllables would be projected on the screen in front of her, and that there was nothing she was required to do but relax and look at the slides. She was not told how many slides were to be presented. To a question whether an attempt should be made to memorize the syllables, the E replied that this was not necessary. Following electrode attachment and a 5 min resting period, the stimulus programme commenced without warning and continued until the eight stimuli appropriate to the particular condition had been presented. Order of presentation of the trigrams was the same for all Ss and followed the sequence listed above. The eighth trial was thus similar for all Ss, XOC.
Results
and discussion
For each trial, EDRs of 100 ohms or greater occurring within 1 to 5 set of slide onset were scored as responses evoked by the stimulus. There were no differences in magnitude of response between the three groups on trial 1 (F< 1). The mean number of responses over the eight trials and the mean magnitude of response of trial 8 for each group are presented in table 1. Both these indices of habituation showed significant differentiation between the groups: for total number of responses, F(2, 24) = 12.09, p < 0.01, and for mean magnitude on the eighth trial, /;‘(3, 24) = 8.84, p < 0.01. In neither case, however, was the test for linear trend significant: for total number of responses, F( 1, 24) = 3.40, p > 0.05, and for mean magnitude, F(1, 24) = 3.43, p > 0.05.
417
J. G. O’Gorman, B. CrassinilHahituatiorz of’ EDR
Table 1 Total number groups.
of responses
and magnitude
Group
Number
Low similarity Medium similarity High similarity
5.9 5.3 3.9
These
data
indicate
some
of EDR on the final trial for the three experimental
of responses
sensitivity
X hlagnltutlc on trial 8 m ohms 2,000 1,100 600
of electrodermal
habituation
to I qualitative
of the stimulus, similarity. As such they are consistent with Sokolov’s (1969) theory which argues that habituation depends on the neural encoding of characteristics of the stimulus. Stimuli which vary from trial to trial would be expected to slow such a coding process and hence delay habituation. as in the present study. Only differences between identical and dissimilar stimuli were demonstrated, however, and subsequent parametric studies with larger numbers of subjects are necessary to explore the sensitivity of habituation, and hence of the neuronal coding process in Sokolov’s terms, to variation in the elements of a stimulus. Since EDK habituation has been shown to relate to learning m the paired-associate paradigm (Kintsch 1965), mvestigation of the effects of similarity on habituation may provide an approach to the psychophysiological analysis of the long-established concepts of retroactive and proactive inhibition. aspect
References Berlyne, D. E., M. A. Craw, P. H. Salapatck and J. L. Lewis, 1963. Novelty, complexity, incongruity, extrinsic motivation, and the GSR. Journal of Experimental Psycholopy 66, 560-567. Graham, 1;. K., 1973. Habituation and dishabituation of responses innervated by the autonomic nervous system. In: H. V. S. Peeke and M. J. Herz (edA.), Ilabituation. Vol. 1. London: Academic Press. Kintsch, W., 1965. Habituation of the GSR component of the orienting reflex during paired of Mathematical associated learning before and after learning has taken place. Journal Psycllology 2, 330-341. Runquist. W. N., 1966. Verbal behavior. In: J. B. Sidowski (ed.), Experimental methods and instrumentation in psychology. NW York: McGraw-Hill. Sokolov, E. N., 1969. The modcling properties of the nervous system. In: M. Cole and I. Maltzman (eds.), A handbook of contemporary Soviet psychology. New York: Basic Books. Spinks, J. A. and D. A. T. Siddle, 1976. Effects of stimulus information and stimulus duration on amplitude and habituation of the electrodermal orienting response. Biological Psychology 4, 29-40.
SHORT REPORT HABITUATION OF THE ELECTRODERMAL FUNCTION OF STIMULUS SIMlLARITY
J. G. O’GORMAN
Srptembcr
AS A
and B. CRASSINI
Dept. of Pswzhology, University of‘~Vew England, Armidale, of‘Psycholog_v, l2niversit.v of Queensland, Australia
Received
RESPONSE
,Y.S. IV., Australia,
and Dept.
1976
Lists of nonsense syllables varyin g in inter-Item similarity were presented visually to independent groups of female Ss (II = 9) while the electrodermat response was monitored. (;roups in which inter-item similarity was low showed a significantly higher freqtiency of responding throughout the series, F(2. 74) = 12.08, p < 0.0 1. and a significantly larger mean response to the final stimulus in the series, F(_,? 14) = X.84. p < 0.01. The results were interpreted as support for Sokolov’s theory of stimulus coding in habituation.
Studies of the stimulus properties determining habituation of human autonomic responses have been mainly concerned with physical features of the stimulus such as intensity, duration, and interstlmulus interval (Graham 1973). Few studies have examined the importance of qualitative aspects of the stimulus. Berlyne et al. (1963) and Spinks and Saddle (1976) have shown, however, that habituation of the electrodermal response (EDR) is more rapid with simple rather than complex visual stimuli. The present study was undertaken to explore a further quahtative aspect of the stimulus. its similarity‘to other stimuli used to produce habituation. Similarity was mampulated in terms of the duplication of elements in lists of WC trigrams and habituation of EDR was examined.
416
f. C. O’Gorman, 8. CrassinilHabituation
of EDR
Method Twenty-seven female student volunteers within the age range of 17 to 25 years were randomly assigned to one of three treatment groups. From the list supplied by Runquist (1966), 16 CVC trigrams, low in both association value and meanmgfulness, were chosen. They were selected to constitute three series, one of low inter-item similarity (HUJ, QIY, GAQ, WIJ, ZIH, CIJ, KUQ. XOC), one of medium inter-item similarity (XAW, XAB, XIQ, XAK, XIN, XEV, XEP, XOC), and one of high inter-item similarity (XOC repeated eight times). Photographic slides containin g, these syllables in upper-case type were presented to the S using a Kodak carousel projector. Blank slides were interposed between stimulus slides so that projected light was not present during the inter-stimulus interval. A pre-programmed tape driven by the deck of a Sony tape-recorder controlled the interstimulus interval which varied randomly from 15 to 25 sec. Exposure duration of each slide, 2 set, was controlled by a timer which also activated the event marker on an E & M Physiograph 6 used for measurement of EDR. Silver silver-chloride electrodes and a saline jelly electrolyte were used to record EDR from the palmar surface of the middle finger of the left hand and the left wrist. The S reclined on a dental couch 1.8 m in front of the projection screen. The projector and Physiograph were housed in a room adjacent to the experimental room. The S was told that slides containing nonsense syllables would be projected on the screen in front of her, and that there was nothing she was required to do but relax and look at the slides. She was not told how many slides were to be presented. To a question whether an attempt should be made to memorize the syllables, the E replied that this was not necessary. Following electrode attachment and a 5 min resting period, the stimulus programme commenced without warning and continued until the eight stimuli appropriate to the particular condition had been presented. Order of presentation of the trigrams was the same for all Ss and followed the sequence listed above. The eighth trial was thus similar for all Ss, XOC.
Results
and discussion
For each trial, EDRs of 100 ohms or greater occurring within 1 to 5 set of slide onset were scored as responses evoked by the stimulus. There were no differences in magnitude of response between the three groups on trial 1 (F< 1). The mean number of responses over the eight trials and the mean magnitude of response of trial 8 for each group are presented in table 1. Both these indices of habituation showed significant differentiation between the groups: for total number of responses, F(2, 24) = 12.09, p < 0.01, and for mean magnitude on the eighth trial, /;‘(3, 24) = 8.84, p < 0.01. In neither case, however, was the test for linear trend significant: for total number of responses, F( 1, 24) = 3.40, p > 0.05, and for mean magnitude, F(1, 24) = 3.43, p > 0.05.
417
J. G. O’Gorman, B. CrassinilHahituatiorz of’ EDR
Table 1 Total number groups.
of responses
and magnitude
Group
Number
Low similarity Medium similarity High similarity
5.9 5.3 3.9
These
data
indicate
some
of EDR on the final trial for the three experimental
of responses
sensitivity
X hlagnltutlc on trial 8 m ohms 2,000 1,100 600
of electrodermal
habituation
to I qualitative
of the stimulus, similarity. As such they are consistent with Sokolov’s (1969) theory which argues that habituation depends on the neural encoding of characteristics of the stimulus. Stimuli which vary from trial to trial would be expected to slow such a coding process and hence delay habituation. as in the present study. Only differences between identical and dissimilar stimuli were demonstrated, however, and subsequent parametric studies with larger numbers of subjects are necessary to explore the sensitivity of habituation, and hence of the neuronal coding process in Sokolov’s terms, to variation in the elements of a stimulus. Since EDK habituation has been shown to relate to learning m the paired-associate paradigm (Kintsch 1965), mvestigation of the effects of similarity on habituation may provide an approach to the psychophysiological analysis of the long-established concepts of retroactive and proactive inhibition. aspect
References Berlyne, D. E., M. A. Craw, P. H. Salapatck and J. L. Lewis, 1963. Novelty, complexity, incongruity, extrinsic motivation, and the GSR. Journal of Experimental Psycholopy 66, 560-567. Graham, 1;. K., 1973. Habituation and dishabituation of responses innervated by the autonomic nervous system. In: H. V. S. Peeke and M. J. Herz (edA.), Ilabituation. Vol. 1. London: Academic Press. Kintsch, W., 1965. Habituation of the GSR component of the orienting reflex during paired of Mathematical associated learning before and after learning has taken place. Journal Psycllology 2, 330-341. Runquist. W. N., 1966. Verbal behavior. In: J. B. Sidowski (ed.), Experimental methods and instrumentation in psychology. NW York: McGraw-Hill. Sokolov, E. N., 1969. The modcling properties of the nervous system. In: M. Cole and I. Maltzman (eds.), A handbook of contemporary Soviet psychology. New York: Basic Books. Spinks, J. A. and D. A. T. Siddle, 1976. Effects of stimulus information and stimulus duration on amplitude and habituation of the electrodermal orienting response. Biological Psychology 4, 29-40.