- Email: [email protected]
Effects of an attention-demanding task on habituation and recovery to change of the skin conductance response
278
D. Papakostopoulos,
ed. / Psychophysiology
Socret,v ahstructs, 1981
the absence of a button-press response. Additionally, the effect of stimulus degradation is examined separately for stimulus- and response-synchronized ERP waveforms. Nine right-handed male subjects were instructed to discriminate between two tachistoscopically presented letters by pressing a button under the right hand (Go), or to withhold the response (No-Go). Letters could be either intact or degraded. The four trials types (No-Go Intact, No-Go Degraded, Go Intact, Go Degraded) were presented randomly with equal probabilities. Stimulus synchronized ERP’s were averaged separately for each trial type and analysed with the principal components (PCA) technique. Factor-scores of the first three rotated factors were submitted to independent repeated ANOVA’s. Response-synchronized ERP’s, associated with the Go trials, were analysed with a peak scoring technique. The main results can be summarized as follows: - Degraded stimuli elicited a late slow positive component (labelled P750) of greater amplitude than intact stimuli. The effect was manifested most clearly in No-Go trials at central and parietal electrode sites. ~ Stimulus degradation did not affect the amplitude of peaks of response-synchronized ERP’s associated with the Go trials. ~ The motor requirements of the task also had a strong effect on the late slow positive (P750) component; this component showed a greater amplitude for Go trials than for No-Go trials. This effect was greatest for Intact stimuli.
Reference R. Kok, A. and Looren de Jong. H. (1980). Components of the event-related potential degraded and ungraded visual stimuli. Biological Psychology, 1I. I 17- 133.
following
EFFECTS OF AN ATTENTION-DEMANDING TASK ON HABITUATION AND RECOVERY TO CHANGE OF THE SKIN CONDUCTANCE RESPONSE Biza STENFERT University
KROESE
of Southampton,
and David SIDDLE
Southampton,
U.K.
Previous work has shown that habituation of the skin conductance response (SCR) component of the orienting response to a task-irrelevant stimulus is
D. Papakostopoulos,
ed. / Psychophysiology
So&t?; crbstructs, 1981
219
delayed as a function of other processing demands. These results can be interpreted in terms of an information-processing analysis of habituation in that the processing resources required by a central task reduce the resources available for analysis of the habituation stimulus. However, despite the lack of observed differences in tonic electrodermal measures, an arousal interpretation of the data cannot be rejected. In these terms, it could be argued that central task performance increases arousal which in turn, retards response habituation. The present experiment was designed to distinguish between informationprocessing and arousal accounts of these findings in a way that did not rely on tonic measures of arousal. Subjects (N ==64) performed a monitoring (central) task in which stimuli were presented at different rates (800 msec and 1000 msec) to create two levels of task demand. During task performance, half the subjects received a series of 21 task-irrelevant tones of 70 dB and 1000 Hz (control groups); the other half (experimental groupsl received the same series except that tone frequency on trial 21 was 670 Hz. Tones were presented at randomly ordered intervals of 20, 30, 40 and 50 set, and skin conductance was measured throughout using a constant voltage system (0.5 V) and a Grass (Model 7) polygraph. An information-processing account argues that stimulus representation in short-term memory will be less well-developed in the high demand (800 msec rate) than in the low demand (1000 msec rate) condition. Thus, the increase in responsiveness from the last training trial to the test trial should be smaller in the former than in the latter. An arousal interpretation simply predicts that all responses will be larger in the high demand condition than in the low, and that the increase in responsiveness from trial 20 to trial 21 will not vary as a function of other processing demands. The results indicated that performance on the central task was better in the low demand groups than in the high, thus validating the rate of presentation manipulation. With regard to electrodermal activity, SCR habituation was slower in the high demand groups than in the low, thus replicating previous results, and stimulus change on trial 21 resulted in a reliable increase in SCR magnitude in experimental groups. More importantly, the increase in SCR magnitude from trial 20 to trial 21 was reliably smaller in the high demand group than in the low. Finally, tonic measures (skin conductance level and frequency of non-specific fluctuations) did not differ between groups. These findings were interpreted as supporting an information-processing approach to habituation.
D. Papakostopoulos,
ed. / Psychophysiology
Socret,v ahstructs, 1981
the absence of a button-press response. Additionally, the effect of stimulus degradation is examined separately for stimulus- and response-synchronized ERP waveforms. Nine right-handed male subjects were instructed to discriminate between two tachistoscopically presented letters by pressing a button under the right hand (Go), or to withhold the response (No-Go). Letters could be either intact or degraded. The four trials types (No-Go Intact, No-Go Degraded, Go Intact, Go Degraded) were presented randomly with equal probabilities. Stimulus synchronized ERP’s were averaged separately for each trial type and analysed with the principal components (PCA) technique. Factor-scores of the first three rotated factors were submitted to independent repeated ANOVA’s. Response-synchronized ERP’s, associated with the Go trials, were analysed with a peak scoring technique. The main results can be summarized as follows: - Degraded stimuli elicited a late slow positive component (labelled P750) of greater amplitude than intact stimuli. The effect was manifested most clearly in No-Go trials at central and parietal electrode sites. ~ Stimulus degradation did not affect the amplitude of peaks of response-synchronized ERP’s associated with the Go trials. ~ The motor requirements of the task also had a strong effect on the late slow positive (P750) component; this component showed a greater amplitude for Go trials than for No-Go trials. This effect was greatest for Intact stimuli.
Reference R. Kok, A. and Looren de Jong. H. (1980). Components of the event-related potential degraded and ungraded visual stimuli. Biological Psychology, 1I. I 17- 133.
following
EFFECTS OF AN ATTENTION-DEMANDING TASK ON HABITUATION AND RECOVERY TO CHANGE OF THE SKIN CONDUCTANCE RESPONSE Biza STENFERT University
KROESE
of Southampton,
and David SIDDLE
Southampton,
U.K.
Previous work has shown that habituation of the skin conductance response (SCR) component of the orienting response to a task-irrelevant stimulus is
D. Papakostopoulos,
ed. / Psychophysiology
So&t?; crbstructs, 1981
219
delayed as a function of other processing demands. These results can be interpreted in terms of an information-processing analysis of habituation in that the processing resources required by a central task reduce the resources available for analysis of the habituation stimulus. However, despite the lack of observed differences in tonic electrodermal measures, an arousal interpretation of the data cannot be rejected. In these terms, it could be argued that central task performance increases arousal which in turn, retards response habituation. The present experiment was designed to distinguish between informationprocessing and arousal accounts of these findings in a way that did not rely on tonic measures of arousal. Subjects (N ==64) performed a monitoring (central) task in which stimuli were presented at different rates (800 msec and 1000 msec) to create two levels of task demand. During task performance, half the subjects received a series of 21 task-irrelevant tones of 70 dB and 1000 Hz (control groups); the other half (experimental groupsl received the same series except that tone frequency on trial 21 was 670 Hz. Tones were presented at randomly ordered intervals of 20, 30, 40 and 50 set, and skin conductance was measured throughout using a constant voltage system (0.5 V) and a Grass (Model 7) polygraph. An information-processing account argues that stimulus representation in short-term memory will be less well-developed in the high demand (800 msec rate) than in the low demand (1000 msec rate) condition. Thus, the increase in responsiveness from the last training trial to the test trial should be smaller in the former than in the latter. An arousal interpretation simply predicts that all responses will be larger in the high demand condition than in the low, and that the increase in responsiveness from trial 20 to trial 21 will not vary as a function of other processing demands. The results indicated that performance on the central task was better in the low demand groups than in the high, thus validating the rate of presentation manipulation. With regard to electrodermal activity, SCR habituation was slower in the high demand groups than in the low, thus replicating previous results, and stimulus change on trial 21 resulted in a reliable increase in SCR magnitude in experimental groups. More importantly, the increase in SCR magnitude from trial 20 to trial 21 was reliably smaller in the high demand group than in the low. Finally, tonic measures (skin conductance level and frequency of non-specific fluctuations) did not differ between groups. These findings were interpreted as supporting an information-processing approach to habituation.