Bilateral electrodermal activity in waking man

Skin conductance responses were examined bilaterally in a group of 14 normal subjects. Twelve of them were right-handed and two were left-handed. All right-handed subjects exhibited asymmetry in skin conductance level and in skin conductance response during verbal-numerical and visual-imagery tasks. With the visual activity, larger responses were found in the left hand, while during the verbal task, larger responses were recorded from the right hand. The results were interpreted as evidence of hemispheric asymmetry of the electrodermal activity orienting response control mechanisms. More ipsilateral control for the right hand is predicted.     

Reduced electrodermal activity in psychopathy-prone adolescents

This study tests the hypothesis that psychopathy-prone adolescents show reduced anticipatory skin conductance responding. Electrodermal activity was recorded while participants anticipated and responded to a 105 dB signaled or unsignaled white-noise burst. Using an extreme groups design, the authors used Child Psychopathy Scale (D. R. Lynam, 1997) scores from a community sample of 335 male adolescents (age 16) to form control (n = 65) and psychopathy-prone (n = 65) groups. Significantly more psychopathy-prone participants were nonresponders in the signaled anticipatory (p = .014), signaled responsivity (p = .037), and unsignaled responsivity (p = .003) conditions compared with controls. Anticipatory hyporesponsivity of psychopathy-prone adolescents similar to the electrodermal hyporesponsivity found in psychopathic adults suggests that this autonomic impairment is present by adolescence and may predispose individuals to adult psychopathy.     

Sex differences and bilateral electrodermal activity

The present study was aimed at replicating the results of a previous work on sex differences and electrodermal asymmetry from our laboratory (Román,et al. 1987). Skin conductance was bilaterally recorded in a sample of 44 dextral volunteers (22 males and 22 females) during a stimulus-free period, and the performance of two tasks (verbal and spatial). Subjects were grouped into two groups of right-hand and left-hand dominance in their electrodermal responses (EDRs) in accordance with their laterality coefficient scores at rest. During the tasks subjects appeareed clearly differentiated by their lateralization in the magnitude and frequency of EDRs independently of gender: right-hand responders showed higher electrodermal activity on their right hand, while left-hand responders showed higher electrodermal activity on their left hand. Sex differences were not observed within each responsiveness pattern. The orientation of phasic electrodermal changes remained constant throughout the different conditions.     

Behavioral inhibition and electrodermal activity during deception

We tested the assumption that the act of inhibiting ongoing behavior requires physiological work. In a guilty knowledge test (GKT) paradigm, subjects were induced to attempt to deceive the experimenter on two separate occasions while electrodermal activity was measured. For 20 of the 30 subjects, overt behaviors (changes in eye movement and facial expression) were recorded during the second GKT. Results indicated that the incidence of behaviors decreased during their deceptive responses. This behavioral inhibition coincided with increases in skin conductance level. In addition to suggesting nonverbal correlates of deception, the results indicate that long-term behavioral inhibition may be a factor in psychosomatic disease.     

An investigation of bilateral asymmetries in electrodermal activity

Research in cerebral laterality supports the idea that functional differences between the left and right hemispheres exist with respect to cognitive style and perceptual ability. Related research, which has examined autonomic nervous system (ANS) correlates of cerebral laterality, suggests that a component of the ANS, electrodermal activity (EDA), is also lateralized. Some findings in the literature report the occurrence of bilateral asymmetries in phasic and tonic EDA as a function of a left or right hemisphere preference for information processing. This experiment used normal male subjects who were either left or right movers in a test of Conjugate Lateral Eye Movement (CLEM). This selection procedure served to maximize a subject’s preference for either a right or left hemisphere mode of information processing. Bilateral EDA was recorded continuously while subjects performed a visual recognition task using word (left hemisphere) and shape (right hemisphere) stimuli. The data do not support the contention that performance on a procedure chosen to selectively activate a given hemisphere elicits asymmetric tonic and/or phasic EDA. The results show no significant difference in the frequency of elicited skin conductance responses under either of the experimental conditions. Bilateral tonic EDA rose continuously over time and did not vary in either hand as a function of task. The present results fail to offer support for either of the hypotheses which argue for I) increased contralateralexcitation with selective hemispheric activation, or 2) increased contralateralinhibition of the EDR with hemispheric arousal.     

Extraversion and neuroticism: Investigation of resting electrodermal activity

In 1967 Eysenck published his biological account of extraversion and neuroticism. In the same year Claridge identified several problems with this theory. More recently Robinson has detailed a promising modification to Eysenck's theory which addresses many of the issues raised by Claridge. Drawing on Robinson's theory it was hypothesised that differences in resting electrodermal activity (EDA) would contrast extraverted‐neurotics (low arousal) and introverted‐neurotics (high arousal). The Eysenck Personality Questionnaire (EPQ) was used to identify four extreme groups of female participants: extraverted‐stable (n = 16), extraverted‐neurotic (n = 15), introverted‐stable (n = 8) and introverted‐neurotic (n = 16). EDA measures of skin conductance level (SCL) and non‐specific skin conductance response (NS‐SCR) were collected during two rest periods. Planned contrasts between the extraverted‐neurotic and introverted‐neurotic groups provided support for Robinson's theory on SCL but not NS‐SCR. It was argued that the results for NS‐SCR frequency could be accommodated by Robinson's theory if NS‐SCR was conceptualised as a measure of cortical reactivity to unspecified stimuli rather than as a measure of tonic arousal.     

Extraversion and electrodermal activity: arousability and the inverted-U

The Eysenck hypothesis that extraverts are less aroused or more inhibited than introverts has been subjected to a number of tests in the psychophysiological literature. Research to date suggests the need to clearly differentiate between tests of overall group differences in arousal or inhibition and studies of the differential reactions of the two groups to arousal manipulations. Psychophysiological studies of overall arousal differences in our laboratories and elsewhere have yielded somewhat inconsistent results for SCL, nonspecific response frequency, trials-to-criterion habituation and initial response amplitude, though dishabituation results are consistent with the expectation of higher amplitudes in introverts. Far more consistent are findings testing the inverted-U hypothesis, which suggests that introverts reach a point of optimal arousal at lower levels of stimulus input than do extraverts and hence should show earlier asymptotes and decrements in arousal measures. Using stimulus intensity and caffeine to manipulate arousal, we have found supportive results for SCL and several phasic measures, including the initial, test, and dishabituation responses. Overall, findings suggest that the two personality groups differ more clearly in arousability than in overall arousal level and that this difference is most consistent when conditions induce a rapid breakdown of inhibition and increase in arousal. Further research is needed to better understand the conditional relationship of extraversion to arousability, and arousal-manipulation paradigms would appear to be a fruitful initial approach to carrying out the needed research.     

Attention of preschool children: electrodermal activity during auditory stimulation

Electrodermal activity during passive and active listening tasks of 43 healthy preschool children (aged 4 yr., 8 mo. to 6 yr., 5 mo.) was studied. The procedure included the following phases: baseline recording (3 min.), a passive listening task, instructions, and an active listening task. An increase in mean amplitude of skin conductance response (SCR) was found during the active listening task over the level for the passive listening task over 10 trials. On the passive listening task from Trial 1 to Trial 10, habituation of mean SCR amplitude occurred. The younger children, moreover, exhibited significantly greater habituation than the older children. Habituation of mean SCR amplitude did not occur during the active listening task. No significant difference was found in mean SCR amplitude during the active listening task for the two age groups. The children seemed to pay more attention during the active listening task than during the passive listening task. The younger children, moreover, are believed to have shorter attention spans.     

Sex differences,activation level,and bilateral electrodermal activity

The effects of the activation level and subject’s sex on bilateral skin conductance measures were studied. Thirty right-handed subjects (15 males and 15 females) were exposed to three types of stimulus conditions: rest-period, verbal task and spatial task. Results showed that no relationship was observed between EDA asymmetry and the increase in the activation level induced by the verbal and the spatial tasks. Males showed both higher SCRs and greater frequency of responses on the left than on the right hand. The direction of electrodermal asymmetry remained constant regardless of the stimulus conditions. It was concluded that sex differences are important in the study of EDA asymmetry and that this asymmetry appeared to depend on peripheral variations.     

Individual differences in electrodermal activity as a function of subjects' anxiety

The present study examines the relationships between electrodermal activity (EDA) and anxiety in an attention demanding task, by looking at the neuropsychology of individual differences. 261 normal volunteer female students completed the Cattell anxiety form, and only subjects with extreme anxiety scores (deciles 0, 1 and 2 on the one hand, N = 22; deciles 9 and 10 on the other hand, N = 24) were retained. Subjects were presented a set of 16 stimuli (8 neutral and 8 emotional slides) in a randomized order (different for each subject), of 35 msec and 1 sec duration and a randomized inter-stimuli time of average 45 sec. Skin conductance levels (SCLs), interstimuli spontaneous fluctuations (SSCRs), skin conductance response (SCR) amplitudes and electrodermal latencies were recorded, as well as skin temperature (ST). Highly anxious subjects showed significantly lower SCLs, lower SCR amplitudes, fewer interstimuli SSCRs and longer latencies than subjects with low anxiety, whereas ST did not differ between groups. These results, showing that in normal subjects there are individual electrodermal differences as a function of trait-anxiety scores, are discussed both in terms of individual differences in self-regulatory neural processes and in reference to Gray's anxiety theory.     

Extraversion and arousal: Effects of attentional conditions on electrodermal activity

Recent work has demonstrated that introverts show arousal decrements with increasing caffeine dosages under nonsignal conditions, but reverse this pattern under signal conditions. Other work, particularly in the areas of vigilance and memory, has pointed to greater attentiveness in introverts than extraverts. It was therefore hypothesized that the two groups would respond differentially under signal and nonsignal conditions as a function of attentional variations. The present study tested introverts and extraverts in a habituation paradigm involving systematic manipulation of signal and attentional conditions. Half of each personality group was randomly assigned to a distraction condition, the other half to an attending condition. Each S received two blocks of 19 habituation trials, a test stimulus and a dishabituation stimulus. In one of the two trial blocks, each stimulus was preceded by an auditory preparatory signal. Results showed that introverts gave larger SCRs, had higher SCLs, and showed greater dishabituation than extraverts. The signal reduced responding significantly more in introverts than in extraverts, and introverts were less affected by the distraction condition than were extraverts. Finally, extraverts showed more rapid habituation under nonsignal conditions and the signal produced a greater increase in habituation rate for introverts than for extraverts. Results were basically supportive of hypotheses derived from the Eysenck theory.     

Hemispheric asymmetry and electrodermal activity in orienting and pavlovian conditioning paradigms

Three experiments on lateralization of electrodermal orienting and conditioned behavior are reported. The basic findings show effects of hemispheric asymmetry on initial magnitude and rate of habituation of phasic stimulus-elicited electrodermal responses. In summary, responses to verbal stimuli repeatedly flashed to the right visual half-field are larger than corresponding responses in the left half-field. Similarily, spatially relevant stimuli initially presented to the left half-field result in larger responses than when the same stimuli are repeatedly presented in the right half-field. In the auditory modality, data show asymmetrical control of responding to verbal material in a dichotic conditioning paradigm with greater resistance to extinction when the conditioned stimulus is initially fed only to the left hemisphere as compared to when it is fed only to the right hemisphere. It is argued that the present approach taps on basic mechanisms for the lateralization of attentional and associative functions.     

Effect of exteroceptive feedback in controlling electrodermal activity in pre-conditioned fears.

Ss with a strong fear of snakes were taught to increase and decrease their skin resistance during practice sessions with a continuous visual display. Ss were not aware that they were increasing or decreasing their levels of skin resistance and attempted only to influence the magnitude of the multimeter display, the polarity of which was controlled by the experimenter. The study used a within-subjects reversal design to investigate whether bidirectional control could be acquired over skin resistance level. To investigate whether this acquired control could affect the magnitude of elicited pre-conditioned autonomic responses, a pre- and post-training comparison was made between the GSRs elicited during test sessions in which Ss viewed slides of snakes while attempting to influence their electrodermal activity with the assistance of the visual display. The results suggest that Ss are able to acquire voluntarily bidirectional control of their level of skin resistance with continuous visual feedback and that this control can either depress or facilitate the magnitude of pre-conditioned emotional responses as a function of visual feedback.     

Effects of attention state on electrodermal activity during auditory stimulation of children.

During passive and active listening tasks electrodermal activity of 49 healthy school children was studied. The procedure included baseline recording, a passive listening task, instructions, and simple and discriminative active-listening tasks. On the passive task from Trials 1 to 10, habituation of the amplitude of the skin conductance response (SCR) occurred. Habituation of SCR amplitude did not occur during the active tasks. The children seemed to pay more attention during the active tasks than during the passive task, since the need to press the key is apt to require and may even increase general attention. As for temporal variables of SCR, the frequency of spontaneous SCRs showed a significant negative correlation with SCR latency and rise time. Reaction time exhibited a significant negative correlation with age. An increase in reaction time was found during the discriminative active-listening task over that for the simple active-listening task during the course of 10 trials. The younger children (6-8 yr.) seemed to require longer to pay attention than the older ones (10-12 yr.). Children seemed to pay more attention during the discriminative than during the simple active-listening task, since the need to press the key for discrimination should require and is likely to increase general attention.     

Sensation seeking: Differential effects of relevant,novel stimulation on electrodermal activity

Zuckerman's (1984) theory suggests that differences in brain catecholamines may cause high sensation seekers (HSS) to have more excitable central nervous systems and hence, display greater arousal then low sensation seekers (LSS). The present study attempted to assess the relationship of sensation seeking to electrodermal activity (EDA) under conditions of relevant, novel stimulation. EDA was measured in extreme groups of HSS and LSS who were exposed to tones and to multiple series of varied, relevant, novel stimuli presented as words, slides and video-taped scenes. Results showed larger initial responses in HSS than LSS under all types of stimulation. There was a similar group difference across all trials for relevant, novel word and video scene stimuli. HSS also had higher SCLs for words. Results were interpreted as supportive of hypothesized group differences under restricted conditions.     

Error detection and error memory in spatial navigation as reflected by electrodermal activity

The study investigated spatial navigation by means of electrodermal activity (EDA). Two groups of healthy subjects (group 1, age <38; group 2, age ≥38) were recorded during navigation through two 3-D virtual mazes differing in difficulty, that is, Maze Simple (MazeS) and Maze Complex (MazeC). Our results show (1) an effect of difficulty, that is, larger skin conductance responses (SCRs) and slower velocity profiles while navigating through MazeC as compared to MazeS. (2) An effect of age, that is, larger SCRs and faster velocity profiles in younger subjects (group 1) compared to older subjects (group 2). (3) An effect of maze region, that is, SCRs increased when subjects entered dead ends with group 1 (young group) decreasing in velocity, whereas group 2 (old group) increased in velocity. (4) And an error memory effect, that is, subjects who remembered an error at a given decision point (crossroads preceding dead ends in MazeC) from previous trials, and then if they did not repeat that error, elicited decreased SCRs as compared to subjects who did not remember and subsequently repeated an error. The latter aspect is the most impactful as it shows that EDA is able to reflect error detection and memory during spatial navigation. Our data designate EDA as suitable monitoring tool for identification and differentiation of the affective correlates underlying spatial navigation, which has recently attracted researchers’ attention due to its increased use in 3-D virtual environments.     

Smoking,personality, and imagery preference in Relation to spontaneous bilateral electrodermal activity

Effects of smoking on spontaneous bilateral skin conductance were studied as a consequence of interactions with set and setting. Bilateral skin conductance was recorded in six men and six women who smoked and an equal number of nonsmokers on two different days. On the first day, spontaneous electrodermal activity was recorded before and after a 10-minute rest period during which half the smokers smoked a cigarette. On the second day, one week later, spontaneous activity was again recorded before and after a 10-minute rest period during which the remaining smokers smoked a cigarette. Nonsmokers did not smoke at any time. Following smoking there was a significant negative correlation between a preference for visual over nonvisual imagery and spontaneous skin conductance responsivity in the left as compared to the right hand. Correlations were significantly different in smokers and nonsmokers. Smokers showed significantly greater preferences for either visual or nonvisual imagery than nonsmokers. Nonresponding nonsmokers were higher on the psychoticism (P) scale of the Eysenck Personality Questionnaire (EPQ) than responding nonsmokers. Smokers scored higher on P than nonsmokers. Interactions between personality, cognitive style, and the experimental situation, set, and setting were discussed in relation to the arousing effects of nicotine.