PHYSIOLOGICAL AND PERSONALITY CORRELATES OF COMMISSION ERRORS IN AN AUDITORY VIGILANCE TASK

To determine correlates of the tendency to make errors of commission in a vigilance task, 31 Ss worked at a task of listening to recorded digits for 48 min and reported odd-even-odd digit sequences. Reports of “signals” where signals did not actually occur constituted commission errors. While S was engaged in the vigilance task skin conductance was continuously recorded. A measure of extra-version and neuroticism was available for each S. The tendency to make commission errors was associated with decrement in the detection of real signals over time, low GSR amplitude at detection points, and low initial orienting response. Commission errors were positively related to extraversion and unrelated to neuroticism. It was concluded that commission errors are made by Ss who are low in arousal level, subject to vigilance decrement, and likely to score higher on extra-version.     

Psychopathy and Physiological Activity In a Mixed-Motive Game Situation

Heart rate (HR) and skin conductance (SC) were recorded while 17 psychopathic (P) and 17 nonpsychopathic (NP) inmates (referred to as A) were engaged in a mixed-motive game situation with another S (referred to as B). On each trial A had to choose the intensity of shock to be delivered to himself and to B. B then was given a chance to retaliate, although his choices were actually overridden by the experimenter. A 10 sec tone (CS) preceded delivery of shock to each S. There were no differences between Groups P and NP in the intensity of shock chosen for themselves and for the other (B) Ss. Compared with Group NP, Group P gave small unconditioned skin conductance (SC) responses to shock directly received and to shocks delivered to the other S. There were no differences between groups in the unconditioned HR response to either direct shock (acceleration) or to shocks delivered to the other S (slight deceleration). Group P gave small electrodermal orienting responses (ORs) and anticipatory responses (ARs) to the CS preceding shock to self and shock to other; Group NP gave relatively large ORs and ARs to the CS preceding shock to self, and small ones prior to shock to other. Both Groups gave a biphasic conditioned HR response–acceleration followed by deceleration; each component was larger in Group P than in Group NP, and the acceleratory component in Group P appeared on the first trial. The electrodermal data were consistent with the view that psychopaths experience little fear arousal prior to reception of aversive stimuli by themselves or by others. It was suggested that the anticipatory HR responses of the psychopathic Ss were part of an adaptive response that helped them to cope with stress.     

SLEEP MENTATION AND AUDITORY AWAKENING THRESHOLDS

Auditory awakening thresholds (AATs) were assessed in 53 Ss during all stages of sleep and at various times of night. Sixteen of these Ss met previously devised criteria for an AAT light-sleep group (LSG) and 16 for an AAT deep-sleep group (DSG). Reports of mental activity were collected during awakenings from REM and NREM sleep and rated on a standard questionnaire by Ss and independent judges. The REM mentation of the LSG and DSG did not differ. However, LSG Ss reported dreaming after 71% of their NREM awakenings, while DSG Ss claimed to have been dreaming after only 21% of their NREM awakenings. This difference was supported by other rating scales and by the independent judges. An hypothesis was offered which suggests that dreaming is a function of the level of cerebral arousal in the absence of reality contact, regardless of the stage of sleep, and that LSG Ss, as evidenced by several criteria, were more cerebrally aroused during NREM sleep than DSG Ss.     

Experimenter and Subject Sex Effects In the Skin Conductance Response

The present study was designed to determine the significance of the experimenter's sex on the subject's skin conductance responsiveness and to ascertain the nature and extent of sex differences in basal skin conductance, skin conductance response (SCR) magnitude, and spontaneous skin resistance (SRR) activity. The responses of 30 male and 30 female Ss were recorded by 3 male and 3 female experimental assistants. Following a brief adaptation period, all Ss received 20 5-sec bursts of 75 dB white noise. Variable stimulus intervals were employed. Male Ss serving in the female E condition evidenced significantly higher basal conductance levels and a more rapid decrease in basal conductance levels over trials. Skin resistance response magnitude data showed a significant Experimenter Sex X Trials interaction such that all Ss serving in the female E condition failed to habituate. An analysis of spontaneous SRR activity showed that Ss serving in the other-sex E condition emitted more spontaneous responses. All Ss showed a significant decrease in spontaneous activity across trials.     

Stuck on you: Face-to-face arousal and gaze aversion in Williams syndrome

Introduction. During face-to-face questioning typically developing children and adults use gaze aversion (GA), away from their questioner, when thinking. GA increases with question difficulty and improves the accuracy of responses. We investigate whether individuals with Williams syndrome (WS), associated with hypersociability and atypical face gaze, use GA to manage cognitive load and whether physiological arousal is associated with looking at faces.

Methods. Two studies were conducted by: (1) recording changes in the participants’ skin conductance levels whilst manipulating task difficulty and gaze direction and (2) calculating the amount of GA away from the experimenters’ face whilst answering questions of varying difficulty.

Results. In Study 1, WS was associated with general hypoarousal, and face arousal effects were found for both Williams syndrome and typically developing participants. In Study 2, participants with WS showed prolonged face gaze under high task demands; however, question difficulty did increase GA.

Conclusions. Looking at faces is demanding, even for individuals with WS. Decreased physiological arousal may allow individuals with WS to hold face gaze for prolonged periods of time, but looking at faces does increase baseline arousal level. The results are discussed in terms of social skills training and teaching methods appropriate for WS.     

Resting physiological arousal is associated with the experience of music-induced chills

In the study of emotion and autonomic nervous system functioning, resting physiological arousal is usually considered a negative characteristic. The present study examined the relationship between resting physiological arousal and positive emotional experience linked to psychophysiological arousal. We assessed resting physiological arousal using markers as high skin conductance level and low respiratory sinus arrhythmia, measured just before participants listened to their favorite music. Participants reported the sensation of chills (goose bumps, shivers) by pressing a mouse button while listening. The results indicated that individuals with resting physiological arousal frequently experience music-induced chills, which evoked unambiguous pleasurable feelings and an increase in skin conductance response. The current results, and the previously demonstrated relationship between resting physiological arousal and negative emotionality linked to psychophysiological arousal (e.g., anxiety, panic), suggest that resting physiological arousal may reflect sensitivity to psychophysiological arousal with both intense positive and negative emotions.     

Age Differences in the Effect of Epidermal Hydration on Electrodermal Activity

The effect of epidermal hydration on skin potential and conductance measurements was investigated in young and old men. The condition of least hydration used a 0.5% KCl glycol electrolyte. Two conditions used a 0.5% aqueous KCl electrolyte differing in that the most hydrated site received a 15-min pretreatment of soaking in distilled water whereas the intermediate hydration site received no pretreatment. These hydration conditions were used in recording three channels of skin potential and three channels of skin conductance during three tasks: 1) tone presentations after rest, 2) simple reaction time, and 3) choice reaction time. There were no significant age differences in the effect of electrolyte on skin conductance level and response. There were age differences in the effect of electrolyte on skin potential level (SPL) and response (SPR). Young adult SPR was monotonically related to hydration with the largest response magnitude occurring with the least hydration. Electrolyte did not significantly affect SPR magnitude of the aged. For the young subjects, SPL was monotonically related to hydration with the most negative SPL occurring with the least hydration. For the aged subjects, the least negative SPL occurred in the condition of least hydration. We postulate that this reversal in the hydration/SPL relationship in old age reflects a reversal in the relative magnitudes of sweat gland and epidermal potentials: in old subjects the epidermal potential is greater than the sweat gland potential.     

PHYSIOLOGICAL AND BEHAVIORAL INDICANTS OF ACTIVATION

The present study demonstrates that various central and peripheral physiological variables are similarly altered by experimentally induced changes in activation while being dissimilarly altered during the course of a trial by unknown factors. That is, both general and specific physiological changes are demonstrated in a single experiment. Activation level was experimentally altered by having S (a) react to light flashes under threat of shock, (b) react to flashes without any such threat, and (c) passively observe light flashes. Evoked cortical potentials, heart rate, skin conductance, and muscular tension were similarly affected by these experimental conditions, but the variables showed differential changes over time. It was concluded that these physiological processes simultaneously reflect both generalized arousal and directionally fractionated activity.     

Response Requirements and Directional Fractionation of Autonomic Responses

Physiological responses were monitored while 27 male Ss were shown a series of 45 colored slides of homicide victims. Nine of the Ss were required to simply look at each slide (Nonraters), 9 were required to push 1 of 7 buttons, after each trial to indicate how disturbing they found the slide to be (Raters). Evidence for directional fractionation of autonomic responses to the slides was obtained for only the Nonraters. Their responses included cardiac deceleration, an increase in skin conductance, digital vasoconstriction, and cephalic vasodilation. The Raters responded with cardiac acceleration, an increase in skin conductance, and both digital and cephalic vasoconstriction. The Raters also showed a larger increase in tonic skin conductance over trials than did the Nonraters. To determine whether the physiological responses of the Raters were influenced by the requirement to make a motor response, 9 other Ss pressed a button after each slide. The physiological responses of these latter Ss were almost identical with those of the Nonraters. The results are consistent with the hypothesis that the requirement to rate the stimuli was associated with appraisal and cognitive elaboration. They also indicate that response requirements can have a profound effect upon autonomic responsivity.     

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.     

THE RELATION OF PALMAR SWEAT GLAND ACTIVITY TO LEVEL OF SKIN POTENTIALAND CONDUCTANCE

The role of sweat gland activity in the mediation of skin potential and skin conductance levels was investigated. l-Hyoscyamine was introduced into the fingertips by iontophoresis to eliminate sweat gland activity, and d-hyoscyamine, an inert analog of the l-isomer, was used as a control for ion size. Neostigmine was used to potentiate sweating. l-Hyoscyamine significantly decreased skin conductance level and the number of active sweat glands and reduced the negativity of skin potential level, but neostigmine, which promoted sweating and skin conductance, did not increase the negativity of skin potential. The lowering of skin potential on the denervated hand of a hemi-sympathectomized patient was found to be similar in magnitude to the decrease in skin potential due to pharmacological elimination of sweat gland activity. The results are discussed in relation to hypotheses concerning the mechanism of skin potential.     

Habituation of Fear: Effects of Intensity and Stimulus Order

This study investigated snake-fearful subjects' skin conductance, heart rate, and fear ratings to repeated presentations of seascape and snake films (10–13 sec duration). The films sampled three levels of fear intensity and were displayed in ascending, descending, or nonsystematic orders; additional Ss viewed only high-fear material. A linear relationship with fear intensity emerged for fear ratings, but not for physiological measures. Differences found between orders in patterns of habituation were concordant for cardiac rate and fear ratings; relative to the other orders, the ascending sequence habituated less and displayed sensitization to material of higher fear levels. In all orders, there was marked habituation of physiological responses, especially in the first session. The possible role of adaptation level and implications of the data for desensitization and flooding were noted.     

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.     

EEG AND AUTONOMIC RESPONSE PATTERN DURING WAKING AND SLEEP STAGES

The response hierarchy of EEG and autonomic variables to tones of increasing intensity was studied during waking and sleep stages 2, REM, and SW (3 & 4 combined). Tones of 1000 Hz (5 sec duration, 55 sec ISI) were presented to 35 young adult male subjects. During waking, the tones began below awake auditory threshold and increased by 5 db until a motor response (button press) was made. During sleep, tones began at awake threshold and went to arousal threshold, i.e., motor response and/or an EEG change indicative of arousal. Changes in EEG, finger pulse amplitude, heart rate, skin potential, skin resistance, and respiration period were measured for each stimulus and were compared to a pseudostimulus response scored 25 sec prior to the actual stimulus. In the awake state, statistically significant responses (p < .05) were found for EEG, finger pulse, heart rate early deceleration, skin potential, and skin resistance to the tone at awake threshold, but not to tones at lesser db levels. During sleep, significant EEG responses were present to tones 30–25 db below arousal threshold, finger pulse 20–15 db below, and heart rate acceleration 20–5 db below. Significant skin potential, skin resistance, and motor responses were seen only at arousal threshold. Thus, in sleep, in contrast to waking, there were clear responses to stimuli below the arousal threshold, and there was definite ordering of the appearance of the various responses: EEG preceded the cardiovascular, with electrodermal and motor occurring only at arousal. This order was constant over sleep stages. Arousal thresholds were very similar across sleep stages in day sleepers (approximately 35 db above awake threshold). The threshold during stage 2 for night sleepers was about 15 db lower than that for day sleepers.     

Psychophysiological discriminants of depression at rest and in response to stress

Examined heart rate, skin conductance, and finger pulse amplitude at rest and in response to stress in a group of 10 chronically depressed Ss and a closely matched set of controls. While all physiological channels revealed a significant main effect attributable to the conditions of rest, anticipation of stress, and stress, only the skin conductance channel revealed a significant group effect. No significant interaction effect was revealed for any of the channels. The results indicate that skin conductance level may have some potential in assessing the level of depression in clients and that attempts to control directly skin conductance level, as in biofeedback, may prove to be a useful adjunct in the treatment of depression with the characteristics employed in this study.     

Another Look at the Relationship of Electrodermal Activity to Electrode Contact Area

The present study was undertaken lo reexamine the hypothesis that the relationship between skin conductance and electrode size is monotonic and linear. Skin conductance activity was recorded from 48 right-handed male subjects using 6 different sixes of electrode collars ranging in exposed surface area from .131 cm² to .786 cm². The dependent measures were skin conductance level (SCL); skin conductance response (SCR) amplitude to a series of 8 loud tones; latency, rise time, and recovery half-time of the first tone elicited response; (he largest self-generated SCR; and the number of nonspecific responses. The results indicated a significant linear relationship between contact area and SCL, stimulus and self-generated SCR amplitude, and the number of nonspecific responses. Latency was not affected by electrode size although the other time-based measures were. Differences in skin conductance activity were found among different palmar recording sites. The observed linear relationship between electrode size and electrodermal measures has implications for current models of electrodermal activity and for the comparison of results across studies in which different electrode contact areas are used.     

Physiological responses to social and cognitive challenges in 8-year olds with a history of prenatal cocaine exposure

Cocaine-exposed infants have been found to have altered arousal responses but little is known about such responses in later childhood. Physiological responses to stressors were used to assess the arousal modulation of school-aged, cocaine-exposed children (n = 73) and two contrast groups, socioeconomically-matched controls (n = 58) and children with behavioral disturbance (n = 35). The behaviorally disturbed group had the highest heart rate across conditions but demonstrated a pattern of hyporesponsiveness to the stressors. They had the smallest decrement in skin conductance response at baseline and the least recovery of skin conductance response following exposure to stressors. Cocaine-exposed children demonstrated greater acceleratory responses to the stressors as indexed by their skin conductance level and were intermediate between the socioeconomically-matched controls and children with behavioral disturbance in recovery of skin conductance response following stressors. Altered arousal responses associated with prenatal cocaine exposure persisted into middle childhood but were different from those found in behaviorally disturbed children.     

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.     

Oxytocin response in a trust game and habituation of arousal

Oxytocin may be implicated in various sophisticated human processes, including attachment, trust, social perception, memory, and fear regulation. In this study, we explored the relationship between plasma oxytocin level measured after a task requiring intimate trust (secret sharing) and habituation of autonomic arousal (skin conductance response) in sixty healthy volunteers. Results revealed that oxytocin was elevated in the trust-related condition relative to a neutral baseline. In a cognitive stress condition (mental arithmetic task), there was no significant oxytocin elevation relative to the neutral condition. After controlling for age, gender, education, state anxiety and depression, we found a significant positive relationship between trust-related oxytocin level and habituation of autonomic arousal. This relationship was absent in the case of neutral (trust-unrelated) oxytocin level. These results suggest that the habituation of autonomic arousal is closely related to oxytocin released during trust-related social interactions.     

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.