Overextinction of the Evoked Skin Conductance Response: An EEG Study

The present study was designed to investigate Sokolov's (1963) proposal that overextinction of the orienting response (OR) is related to sleep onset. A series of 80 auditory stimuli was presented to 22 male and female Ss. Although re-evocation of the skin conductance response (SCR) component of the OR occurred, in the majority of Ss, after 40–50 stimulus presentations, this was not accompanied by any change in cortical alertness as measured by integrated EEG output in three frequency bands (2–4, 4–8, and 8–13 Hz). However, the results did indicate that Ss displaying SCR return required more stimulus presentations before initial SCR habituation and displayed more spontaneous fluctuations in skin conductance during the prestimulus period than did non-return Ss. Within the return group, latency of SCR return was negatively related to both spontaneous activity during the prestimulus period and number of stimuli to initial habituation.     

CLASSICAL CONDITIONING OF THE ELECTRODERMAL RESPONSE WITH NOVEL STIMULI

Most attempts to classically condition the electrodermal response (GSR) have used aversive stimuli. A series of 20 novel slides were used as unconditional stimuli in a delayed differential conditioning paradigm involving reinforced and unreinforced conditional stimuli. Thirty female Ss were given 10 habituation trials, 40 conditioning trials of which half were reinforced, and 10 extinction trials. Orienting response, anticipatory response, and post-conditional stimulus response components were analyzed separately for the different series. Differential conditioning was obtained for two of the responses during the conditioning and extinction series. The results indicate that a relatively mild novel stimulus can also effectively condition the GSR.     

EFFECTS OF STIMULUS ORDER AND NOVELTY ON ORIENTING RESPONSES

The effects of stimulus order and novelty upon habituation and dishabituation of the GSR component of the OR were investigated. The numbers 21 to 60 were presented in serial order (Ordered-Novel group), and in random order (Random-Novel group), and the number 21 was repeated 40 times (Similar group). The number 600 was occasionally interpolated among each series. No group differences in magnitude of OR to the first stimulus or in habituation of the OR during the series of numbers were found. Dishabituation due to the interpolated stimulus was found primarily in the Similar group. The results were related to Sokolov's concept of neuronal models used in his theory of habituation.     

Amplitude and Habituation of the Orienting Reflex as a Function of Stimulus Intensity

Two within-S experiments involving 20 Ss each and one between-S experiment employing 100 Ss were performed to examine effects of stimulus intensity on orienting response amplitude and habituation. Five intensities of a 1000 Hz tone were presented, ranging from 0 to 40 dB in Experiment I and from 0 to 80 dB in Experiments II and III. Response measures were skin conductance response (SCR) and heart rate (HR). Skin conductance response amplitude increased monotonically with stimulus intensity while HR deceleration was a generally decreasing function which tended to decrease, increase, and finally decrease again as intensity increased. Not only was deceleration greatest at 0 dB but it was more resistant to habituation. Several intensities of test stimulation were presented after habituating stimuli in the between-S experiment. Skin conductance response to test stimuli was facilitated by habituation at 0 dB and depressed by habituation at 80 dB. The results suggest a direct relationship between stimulus intensity and development of habituation.     

Effects of the Range of Stimulus-Variation Upon Habituation of the Orienting Response

The effects of the range of stimulus-variation upon the habitation and return of the skin resistance response (SRR) component of the orienting response (OR) were investigated in three experiments using human subjects. In Experiment I the habituation and return of the OR were studied in two groups with a wide (Group-W) und a narrow (Group-N) range of stimulus-variation. Habituation in the two groups did not differ, but a differential level of return of the OR to a novel stimulus was observed. In Experiment II the difference in the range was made large and a group presented with a constant stimulus (Group-C) was added. Again Group-W and -N habituated in the same way as Group-C. In Experiment III the upper end stimulus of each group was set at the same intensity. The differential return of the OR disappeared, and as before a differential habituation could not he detected between Groups-W and -N. These findings were discussed in reference to Sokolov's neuronal model of the OR.     

HABITUATION OF THE ORIENTING RESPONSE TO MULTIPLE STIMULUS SEQUENCES

The purpose of the study was to test the hypothesis that rate of habituation of the orienting response (OR) to multiple stimulus sequences is a negative function of the uncertainty (H) in the stimulus series. Seven groups of 30 Ss received 10 presentations of a 10 sec light stimulus (S₁) followed immediately by a 1 sec 70 db auditory stimulus (S₂) on 0, 10, 20, 50, 80, 90 or 100 percent of trials. The response measure was change of skin conductance to S₁. Mean conductance change scores of the various groups were closely related to the degree of uncertainty (H) in the stimulus series. The results were interpreted as offering support for Sokolov's OR theory, and the view that, in human information processing, information concerning stimulus probabilities is integrated continuously to form the basis of predictive extrapolation.     

RESPIRATION AND SUCKING AS COMPONENTS OF THE ORIENTING REACTION IN NEWBORNS

Respiratory and non-nutritive sucking responses to auditory stimulation were studied in 1- to 5-day old human newborns. Each S was presented 5 stimuli, each 4 times, during 4 sessions at 24 hour intervals. The stimuli varied in intensity and intermittency. Stimulus onset and offset shortened sucking bursts during Sessions I-III, but in Session IV stimulus offset lengthened sucking bursts. In general, respiration was accelerated by stimulus onset and decelerated by stimulus offset. However, in Session IV respiratory deceleration occurred to both stimulus onset and offset. Respiratory deceleration also occurred to low intensity stimuli in Sessions I-III. Respiratory acceleration and sucking inhibition were discussed as components of the newborn's defense reaction (DR) to most stimulation. Respiratory deceleration was related to appearance of orienting reaction (OR) after habituation of DR. Ss' respiratory responsivity and sucking responsivity were highly correlated.     

THE INFLUENCE OF SOME PSYCHOLOGICAL FACTORS ON LATENCY OF THE GALVANIC SKIN REFLEX

The purpose of this study was to examine the effect of differences in motivativation and in attention on latency of the endosomatic GSR. Using verbal instructions, two different levels of motivation were induced in a group of 37 Ss who performed a simple reaction task in which they pressed a button whenever a 250 cycle tone was presented. The same tone also served as a stimulus for eliciting the GSR. In a second experiment, 42 different Ss performed a similar reaction task, but in this case the stimulus was the 250 cycle tone or a 1,000 cycle tone of equal subjective intensity. Ss were asked to give a voluntary response to all tones irrespective of frequency and then, later on, to respond only when the 1,000 cycle tone was presented. Although voluntary reaction times were significantly shorter under conditions of high as compared with low motivation, latency of the GSR did not differ for the two conditions. In the second experiment, significantly shorter GSR latencies were recorded under the condition where Ss were required to pay closer attention to the stimulus.     

PERSONALITY AND AROUSAL CORRELATES OF SPECIFIC GALVANIC SKIN RESPONSES

Basal skin resistance (BSR) and galvanic skin responses (GSR) to five intensities of sound and light were recorded on four occasions in 32 student subjects (Ss). These occasions were assumed to include unfamiliarity and basal and real life stress conditions. All Ss completed the MMPI, California Personality Inventory, Wechsler Adult Intelligence Scale, Clyde Mood Scale and Examination Anxiety Scale. GSR amplitude was greater under conditions of unfamiliarity, alertness (by electroencephalographic criteria), and higher intensities of stimulation in both stimulus modalities. It was not greater during the presumed stress period. High ego strength-high Barrier score Ss showed a greater GSR amplitude than low ego strength-low Barrier Ss. Test indices of anxiety generally were not related to GSR amplitude, nor were other personality and mood variables.     

Detection of Information and GSR Habituation: An Attempt to Derive Detection Efficiency From Two Habituation Curves

The study attempts to describe the detection of information paradigm, based on differential GSR reactivity in terms of basic habituation processes. Two GSR habituation curves, for relevant and neutral stimuli, were generated rated on a sample of 83 Ss. Relevant and neutral stimuli exhibited similar habituation curves, From these two habituation curves it was possible to predict in a meaningful fashion the characteristics of standard information detection experiments using a notion of dichotomization. This notion refers to separate habituation processes for the relevant and neutral stimulus categories. The predictions were tested on an additional sample of 102 Ss. It was found that without additional assumptions it was possible to predict, at least the order, of the efficiencies of detection in various information detection tasks. In light of the present results, consideration was given to Sokolov's concept of “signal value.”     

A COMPARISON OF GSR AND SUBJECTIVE ADAPTATION TO STRESSFUL STIMULI

The purpose of this study was to compare subjective and physiological adaptation, as measured by magnitude of GSRs, to electric shock and auditory noise. In Exp. I, 48 Ss received 15 shocks of constant intensity, one subgroup always receiving low shocks and the other high. Subjects were told that shock intensity would vary and rated the intensity of each shock immediately following its presentation. In Exp. II, the same procedure was followed with 50 different Ss, using noises instead of shocks. Shock Ss showed subjective adaptation but no GSR adaptation. Noise Ss showed GSR adaptation with an increase in subjective intensity reports. The importance of anticipation, in terms of level of arousal at the onset of the session, is discussed.     

ELECTRODERMAL AND CARDIAC RESPONSES OF SCHIZOPHRENIC CHILDREN TO SENSORY STIMULI

The reactivity and habituation of autistic schizophrenic and normal children were compared using a variety of stimuli. The first two stimulation conditions were 15 tone trials followed by a novel tone stimulus, and 15 periods of darkness followed by a single period of partial illumination. Order of these stimulation conditions was counterbalanced in a groups × order × trials anova factorial design. Other stimuli were tones varying in intensity and photic flashes presented in fixed order following the first two conditions. The two groups differed in magnitude of response to the first 3 tone and illumination change trials, and thereafter showed no differences in habituation or reinstatement to the novel stimulus. This difference consisted of greater responsivity for the normals and was independent of base level, spontaneous activity, order of condition, and type of stimulus. The schizophrenics showed a relationship between GSR magnitude and tone intensity that was similar to the normals' physiological tracking of changing intensity. Results for photic stimulation were the same as for the first two stimulus conditions. The peak-to-valley cardiac measure failed to yield any reliable group differences under any stimulation condition.     

ONSET AND TERMINAL ORIENTING RESPONSES AS A FUNCTION OF TASK DEMANDS

The frequency of response and trials to habituation of the electrodermal onset and terminal orienting response were manipulated as a function of discrimination tasks involving either stimulus content (pitch) or duration. There were no significant differences between the groups on either measure for onset ORs; however, the duration task group demonstrated more TORs and required a greater number of trials to habituate than the content task group. The results, interpreted in terms of the development of cortical models, supported Stern's suggestion that OR and TOR habituation are related to the content and duration of the stimulus respectively.     

RATE OF HABITUATION AND THE LAW OF INITIAL VALUES

The galvanic skin response (GSR) data of two experiments were analyzed in an attempt to determine the effects of tonic shifts in baseline conductance on apparent rate of habituation. The results of the first experiment indicated that rate of habituation is exaggerated when response measures which are not base-independent are employed. The positive correlation found between habituation slope and an index of base-level change in conductance was significantly reduced when autonomic lability scores (ALSs) were used. Thus, base-corrected responses produced less steep habituation functions. The second experiment demonstrated that a tonic increase in conductance occurs to an intense auditory stimulus and that rate of habituation is consequently over-estimated in comparison to that associated with repeated presentation of a mild stimulus.     

Stimulus Repetition, Change, and Assessments of Sensitivities of and Relationships Among an Electrodermal and Two Plethysmographic Components of the Orienting Reaction

Twenty Ss were presented with 15 300-msec tones (for half the Ss) or lights (for the remaining Ss) followed by a change trial to the other modality. There was highly reliable habituation in the electrodermal skin resistance response (SRR) and the plethysmographic pulse volume (PV), but no clear habituation in the plethysmographic blood volume (BV). Change produced reliable increases in all three orienting-reaction (OR) components. Application of signal-detection methods showed SRR to be a more sensitive index of both initial OR and OR to change than either PV or BV, which were not different. Neither PV nor BV were correlated with SRR, but the BV-PV correlations were significant, and, when corrected for attenuation, approximated +.75. The problem of why the plethysmographic OR components sometimes habituate to stimulus repetition, and sometimes do not, was discussed, but it was concluded that while some possible explanations have been eliminated by the present results, the problem itself still awaits solution and poses a challenge to psychophysiologists.     

Race Differences and Experimenter Race Effect in Galvanic Skin Response

The present study was designed to ascertain whether racial differences exist in the several components of the skin resistance response and to assess the importance of the role of the experimenter's race in determining the subject's responsiveness. Basal measures, GSR magnitude, and spontaneous GSR activity of 12 Negro and 12 Caucasian Ss were recorded by 2 Negro and 2 Caucasian experimental assistants matched for age, physical stature, and dress. Following a 15 min resting phase, all Ss received 14 1-sec bursts of 75 dB white noise. Variable stimulus intervals were employed. Significant subject-race effects, but no experimenter-race effects, were found for base level measures. Negro Ss evidenced significantly higher basal resistance levels. Conversely, experimenter-race effects, but no subject-race effects, were apparent in the GSR magnitude data. White Ss showed a significantly slower rate of response magnitude decrease over trials when paired with black Es. A significant decrease in spontaneous activity over time was observed for all Ss.     

HEART RATE, SKIN CONDUCTANCE, AND INTENSITY RATINGS DURING EXPERIMENTALLY INDUCED ANXIETY: HABITUATION WITHIN AND AMONG DAYS

Twenty Ss were divided into two groups according to whether they received as a noxious stimulus in a count-up a mild shock or a punishing sound. Trials were varied over as well as within days. Among the findings: (1) There was considerable evidence of response fractionation among and within measures of heart rate, skin conductance, and rated stimulus intensity. (2) Trials over days exhibited an incubation effect for shock in the skin conductance data, a displacement of maximum heart rate reactivity toward the beginning of the time dimension, and a greater degree of habituation of the rated intensity of the shock stimulus than of the sound stimulus. It was concluded that habituation and incubation reflect cognitive processes, that the forward displacement of heart rate is the result of a centrally mediated inhibitory process, and that the gradient of such inhibition is steeper than the gradient of anxiety.     

Change in Stimulus Conditions and the Orienting Response

A review of studies of the orienting response (OR) to variation in the properties of a stimulus following habituation indicates that not all human Ss respond with an OR to changes of which they are aware and that the only conditions which have been found consistently to elicit the OR are an increase in the intensity of the stimulus and change in the modality of its presentation. These findings pose problems for the theory of the OR advanced by Sokolov (1960) which makes no allowance for a failure to respond to a detectable change in stimulation and which relies for support on evidence that the OR is not elicited solely as a consequence of the activating effects of stimulation. To clarify some of these problems it is suggested that future work should investigate the effect of complete omission of the stimulus on the OR and the contribution of individual differences in physiological responsiveness and perceived significance of a change to elicitation of the OR.     

AUTONOMIC RESPONSES TO AFFECTIVE VISUAL STIMULATION

Physiological responses were recorded while 48 male Ss viewed a series of 30 slides of homicide scenes, nude females, or ordinary objects. Half the Ss saw the same slide 30 times while the others saw a different slide on each trial. The physiological responses given by all six groups involved were those generally associated with an OR—increase in skin conductance, cardiac deceleration, and digital vasoconstriction. In addition, a biphasic cephalic vasomotor response, consisting of constriction followed by dilation, was observed. Stimulus presentation was also accompanied by a sharp reduction in eyeblink rate. The physiological and eyeblink responses given by Ss who saw a different homicide scene on each trial were generally greater and more resistant to habituation than were those given by other Ss. Ss repeatedly shown the same homicide scene gave relatively small cardiac and cephalic vasomotor responses, and showed rapid habituation of the electrodermal response.     

Effects of Changes in Verbal Stimuli on the Skin Conductance Response Component of the Orienting Response

This paper presents three experiments which were designed to investigate the effects of changes in verbal stimulus meaning on magnitude of the skin conductance response (SCR) component of the orienting response (OR). In Experiments 1 and 2, subjects received 12 visual presentations of a single word stimulus followed by a test trial involving change. The results of Experiment 1 (N = 48) indicated that a test stimulus which constituted change in meaning and taxonomic category induced larger responses than did a change in meaning alone, which in turn induced larger responses than did a control condition of no change. Experiment 2 (N = 64) investigated the effects of both semantic and acoustic changes and the results indicated that only semantic changes resulted in test trial SCRs which were larger than those in the control condition. Experiment 3 (N = 48) investigated the effects on SCR magnitude of within- and between-taxonomic category shifts following habituation training with 4 examples of the category. In this case, only the between-category change resulted in SCRs which were larger than those in the control condition of no change. The results of all three experiments were interpreted as support for Sokolov's (1963) claim that the meaning of verbal stimuli is encoded during habituation. Moreover, the results of Experiment 1 indicate that responsiveness on a change trial is a positive function of the amount of change, while the results of Experiment 3 suggest that when a number of examples of a word class are employed during habituation, the semantic characteristics of that class are encoded.