Age-Invariance in the Asymmetry of Stimulus-Evoked Emotional Facial Muscle Activity

This study examined possible effects of aging on the lateralization of stimulus-evoked emotional facial muscle activity. Older participants (mean age 68.4 years) and younger participants (mean age 26.4 years) viewed slides of positive, neutral, or negative emotional content. While participants viewed the slides, bilateral electromyographic (EMG) recordings were obtained from the skin surface over zygomatic and corrugator facial muscles. The participants also made ratings of experienced emotional valence and arousal. Expected patterns of subjective experience and asymmetrical EMG activity were found in response to target stimuli. Greater corrugator muscle activity occurred during presentation of negative stimuli, whereas greater zygomatic muscle activity occurred during presentation of positive stimuli. Consistent with right-hemisphere specialization theories of emotion, left-sided facial EMG activity was consistently greater than that of the right side during presentation of emotional stimuli. However, neither subjective ratings nor EMG patterns showed a significant effect of age group. Such similar patterns of emotional response for the two groups suggest, that the aging process does not produce marked changes in stimulus-evoked emotional experience or in the pattern, magnitude, or lateralization of facial muscle activity associated with emotional states.     

Electrodermal correlates of extraversion, trait anxiety and schitophrenisrn

Abstract.— Recording skin resistance in 34 young women it was found that extraverted subjects showed less responsiveness to moderate intensity stimuli, whereas high neuroticism or anxiety prone subjects showed more spontaneous fluctuations and better electrodermal conditioning when conditioned responses were scored relative to unconditioned responses. Further, the subjects were rated for 'schizophrenism' according to an inventory devised by the authors. The high schizophrenism subjects behaved electrodermally very much like the pre-schizophrenic sample in Mednick and Schulsinger's prospective study of schizophrenia; they exhibited faster recovery, greater response amplitude to aversive stimuli and faster initial habituation to these stimuli.     

Retention of orienting reaction habituation in patients with epileptogenic cerebral tumors

An electrographic study on habituation of the somatic (EMG), autonomic (finger plethysmogram, galvanic skin reaction, respiration, pulse) and EEG (acoustic evoked potential and EEG-blocking reaction) components of the orienting reaction elicited by a repetitive auditory stimulus during successive (weekly) sessions was performed in 41 patients with epileptogenic cerebral tumors (ECT) and in 128 control subjects. The study evidenced significant retention disturbances of orienting reaction habituation (i.e., of learning), the “saving” of stimulations, achieved from one session to the other to obtain the habituation criterion, being lesser in ECT patients than in control subjects. The severity of habituation retention disturbances depended on the tumor site and size, as well as on the electro-clinical form and frequency of seizures. Thus, the most marked habituation retention disturbances were found in patients with temporal or predominantly temporal epileptogenic tumors, in cases with large hemispheric epileptogenic tumors (over 6 cm), in patients with generalized or generalized plus partial seizures, as well as in those with frequent (daily) seizures.     

Constraint, alcoholism, and electrodermal response in aversive classical conditioning and mismatch novelty paradigms

This study investigated whether low levels of the personality trait of constraint and early-onset alcoholism would be associated with deficits in aversive conditioning and smaller responses to novelty in a stimulus mismatch protocol. Personality traits (constraint and socialization) and skin conductance responses (SCRs) during conditioning and novelty paradigms were assessed in alcoholics (n=41) and non-alcoholics (n=32). The conditioning protocol involved measuring SCRs after conditioned stimuli (CS+: tones) paired with shock, CS− tones unpaired with shock, and CS+ probes unpaired with shock. The mismatch protocol involved measuring SCRs to auditory stimuli consisting of a series of 5 pure tones of the same pitch followed a shorter white noise stimulus (the novel stimulus). Contrary to the hypothesis, alcoholics did not differ from non-alcoholics in SCRs to CS+ probes or on the mismatch measure (SCR novel tone—SCR to 5^th tone). Higher levels of constraint and self-reports of fear during conditioning were associated with smaller responses to both the CS+ probes and the CS− tones as well as the mismatch measure within non-alcoholics, but not within alcoholics. In alcoholics, low constraint was associated with greater habituation to CS+ probes, and poor differential conditioning on measures of change across trials in SCR to CS+ probes and CS− stimuli. The results suggest that different processes influence levels of constraint in non-alcoholics and alcoholics. The data indicate that low constraint in non-alcoholics is associated with allocating fewer processing resources to potentially significant stimuli, rather than being associated with a specific deficit in aversive conditioning per se.     

Constraint, Alcoholism, and Electrodermal Response in Aversive Classical Conditioning and Mismatch Novelty Paradigms

This study investigated whether low levels of the personality trait of constraint and early-onset alcoholism would be associated with deficits in aversive conditioning and smaller responses to novelty in a stimulus mismatch protocol. Personality traits (constraint and socialization) and skin conductance responses (SCRs) during conditioning and novelty paradigms were assessed in alcoholics (n=41) and non-alcoholics (n = 32). The conditioning protocol involved measuring SCRs after conditioned stimuli (CS+: tones) paired with shock, CS- tones unpaired with shock, and CS+ probes unpaired with shock. The mismatch protocol involved measuring SCRs to auditory stimuli consisting of a series of 5 pure tones of the same pitch followed a shorter white noise stimulus (the novel stimulus). Contrary to the hypothesis, alcoholics did not differ from non-alcoholics in SCRs to CS+ probes or on the mismatch measure (SCR novel tone-SCR to 5th tone). Higher levels of constraint and self-reports of fear during conditioning were associated with smaller responses to both the CS+ probes and the CS- tones as well as the mismatch measure within non-alcoholics, but not within alcoholics. In alcoholics, low constraint was associated with greater habituation to CS+ probes, and poor differential conditioning on measures of change across trials in SCR to CS+ probes and CS- stimuli. The results suggest that different processes influence levels of constraint in non-alcoholics and alcoholics. The data indicate that low constraint in non-alcoholics is associated with allocating fewer processing resources to potentially significant stimuli, rather than being associated with a specific deficit in aversive conditioning per se.     

Slow wave sleep during a daytime nap is necessary for protection from subsequent interference and long-term retention

While it is now generally accepted that sleep facilitates the processing of newly acquired declarative information, questions still remain as to the type and length of sleep necessary to best benefit declarative memories. A better understanding could lend support in one direction or another as to the much-debated role of sleep, be it passive, permissive, or active, in memory processing. The present study employed a napping paradigm and compared performance on a bimodal paired-associates task of those who obtained a 10-min nap, containing only Stages 1 and 2 sleep, to those whose nap contained slow-wave sleep (SWS) and rapid eye movement (REM) sleep (60-min nap), as well as to subjects who remained awake. Measurements were obtained for baseline performance at training, after a sleep/no sleep interval for short-term retention, after a subsequent stimulus-related interference task, and again after a weeklong retention period. While all groups learned the information similarly, both nap groups performed better than the Wake group when examining short-term retention, approximately 1.5h after training (10-min p=.052, 60-min p=.002). However, performance benefits seen in the 10-min nap group proved to be temporary. Performance after a stimulus-related interference task revealed significantly better memory retention in the 60-min nap group, with interference disrupting the memory trace far less than both the Wake and 10-min nap groups (p<.001, p=.006, respectively). After a weeklong retention period, sleep's benefit to memory persisted in the 60-min nap group, with performance significantly greater than both the Wake and 10-min nap groups (p<.001, p=.004, respectively). It is our conclusion that SWS, obtained only by those in the 60-min nap group, served to actively facilitate the consolidation of learned bimodal paired-associates, supported by theories such as the Standard Theory of Consolidation as well as the Synaptic Homeostasis Hypothesis.     

Flooding therapy: Effectiveness,stimulus characteristics,and the value of brief in vivo exposure

Three analogue experiments examined flooding therapy. Experiment 1 showed that flooding was more effective than standardized desensitization in reducing snake phobia. Experiment 2 examined three different modes of presenting the feared stimuli in flooding: taped auditory presentation, pictorial presentation, and a combination of these two. An additional combination group were given a brief in vivo exposure to the feared object immediately after each of three treatment sessions. Both a behavioral test and subjective estimates of fear showed advantages for the combined group that had the in vivo exposure, although it appeared that auditory instructions to imagine interaction with the snake was the best method for presenting the feared stimuli. Experiment 3 compared the auditory imagined method with and without ‘aversive’ or ‘implosive’ scenes, and with either an immediate or a delayed in vivo exposure. The only procedure to produce marked effects was the one that omitted ‘aversive’ scenes and provided immediate post-treatment in vivo exposure.     

Psychophysiological responses during analogue systematic desensitization and non-relaxation control procedures

This investigation tested the hypotheses than an analogue systematic desensitization procedure (SD) would be both more effective and more efficient than a comparable non-relaxation control procedure (NRC) with respect to subjective report, behavioral and psychophysiological variables. Phobic subjects responded to slides depicting a feared aversive stimulus. The SD procedure resulted in significantly less reported fear, fewer trials to a criterion level of decrease in subjective fear, and significantly greater decreases in ANS baseline measures. However, measures of behavioral avoidance and measures of decrease in psychophysiological responsivity to the aversive stimuli revealed significant changes within both SD and NRC groups, and no significant differences between the groups, whether or not the groups were equated for number of stimulus presentations. The results, indicating equivalent efficacy and efficiency for the SD and NRC procedures, suggested a limited role for relaxation in systematic desensitization. An extinction or habituation hypothesis was supported at the expense of a counterconditioning hypothesis.     

Effects of presenting incidental information in consequent events on future learning

The effects of presenting future target stimuli in the consequent event following correct responses to current target stimuli were examined in two experiments teaching eight students with moderate handicaps to name photographs. In Experiment I, progressive time delay was used to teach two sets of photographs. During instruction, correct responses to one set of stimuli resulted in praise and presentation of the printed word for the person in the photograph (future condition). In the second set, a correct response was followed by praise alone (non-future condition). After establishing criterion level performance on both sets of photographs, students were taught to read the printed word from each of the two sets. Experiment II was a systematic replication of Experiment I. Four students from a different classroom also were taught to name two sets of photographs. An adapted alternating treatments design was used in each experiment. The results indicated that (a) all students learned to name the photographs; (b) presentation of future target stimuli (words) in consequent events resulted in seven of the eight students learning to read some of the words; and (c) the total number of sessions, trials, errors, and percentage of errors     

The effects of postconditioning revaluation of CS1 and UCS following pavlovian second-order electrodermal conditioning in humans

An experiment is described which uses various inferential post-conditioning revaluation techniques in order to clarify the associative substructure underlying Pavlovian electrodermal conditioning in human subjects. This study established a second-order skin conductance response (SCR) by pairing a CS₁ with an aversive 115 dB tone (UCS), and then pairing a different stimulus (CS₂) with CS₁. The second-order SCR survived post-conditioning extinction of the response to CS₁, but was abolished when (i) a post-conditioning habituation procedure resulted in a favourable revaluation of the tone UCS, or (ii) when subjects were given instructions which informed them that there would be no more UCS presentations. These results suggest that in the second-order electrodermal conditioning paradigm described, CR₂ is not mediated by S-R links--as it appears to be in second-order aversive conditioning in nonhuman animals--but is affected by manipulations which modify the subject's cognitions concerning the UCS.     

Habituation during exposure treatment: Distraction vs attention-focusing

To investigate the effects of distraction and attention-focusing during in-vivo exposure to feared stimuli, the responses of 16 obsessive-compulsives with washing rituals were studied. A cross-over design was employed in which 6 of the subjects underwent exposure with attention focusing on the first day followed by exposure with distraction on the second day. The remaining subjects received the reverse order. Habituation of both heart rate and subjective anxiety was observed under both conditions, the rate of habituation tending to remain constant throughout the 90-min exposure. Greater between-session habituation and greater synchrony between the psychophysiological and the subjective measures of anxiety was observed when attention-focusing preceded distraction. Since habituation and synchrony have previously been found to be positively related to treatment outcome, the present results suggest that treatment by exposure to feared stimuli may be more effective if attention-focusing is promoted.     

Personality traits modulate skin conductance response to emotional pictures: An investigation with Cloninger’s model of personality

Several studies found strong relationships between main personality dimensions and emotions, and more particularly between neuroticism and negative emotions, as well as between extraversion and positive ones. In these studies, personality was mainly assessed with respect to the big five model, and emotions were evaluated with subjective rating scales. To extend the exploration of the associations between personality and emotion, the aim of the present study was to investigate the relationships between Cloninger’s dimensions of personality and emotional reactivity assessed by skin conductance response (SCR). In 55 normal subjects, SCR was recorded while they were presented pictures selected as positive, negative and neutral from the International Affective Picture System. The results showed no influence of personality on response magnitude, but subjects with higher harm avoidance scores showed longer half-recovery times for negative relative to neutral pictures. This result is consistent with the dispositional bias of harm avoidance to respond intensely to signals of aversive stimuli.     

Resistance to extinction of conditioned electrodermal responses: a study of the incubation fear hypothesis

In the present study we examined Eysenck's incubation hypothesis of fear. Probability of skin conductance response (SCR) was analyzed for a sample of 79 undergraduate women, ranging in age from 18 to 25 years. Different groups of participants were conditioned to two levels of unconditioned stimuli (UCS) intensity and presented to three levels of unreinforced conditioned stimuli (CS) exposures (extinction phase) in a delay differential conditioning paradigm. The CSs were fear-relevant slides (snakes and spiders) and the UCSs were aversive tones. Analysis did not show a clear incubation effect; instead an increased resistance to extinction of SCR probability in association to the high-UCS and the short unreinforced CS presentation was evident. Findings support partially Eysenck's incubation theory of fear/anxiety.     

How do social fears in adolescence develop? Fear conditioning shapes attention orienting to social threat cues

Social fears emerging in adolescence can have negative effects on emotional well-being. Yet the mechanisms by which these risks occur are unknown. One possibility is that associative learning results in fears to previously neutral social stimuli. Such conditioned responses may alter subsequent processing of social stimuli. We used a novel conditioning task to examine how associative processes influence social fear and attention orienting in adolescents. Neutral photographs were paired with socially rewarding or aversive stimuli during conditioning; a dot-probe task then assessed biases in attention orienting. The social conditioning task modified subjective ratings of the neutral stimuli. Moreover, for the neutral stimulus that was paired with the aversive stimulus, the strength of conditioning showed a relationship with subsequent attentional vigilance. The findings elucidate mechanisms by which negative peer experiences during adolescence may affect emotional processing.     

How do social fears in adolescence develop? Fear conditioning shapes attention orienting to social threat cues

Social fears emerging in adolescence can have negative effects on emotional well-being. Yet the mechanisms by which these risks occur are unknown. One possibility is that associative learning results in fears to previously neutral social stimuli. Such conditioned responses may alter subsequent processing of social stimuli. We used a novel conditioning task to examine how associative processes influence social fear and attention orienting in adolescents. Neutral photographs were paired with socially rewarding or aversive stimuli during conditioning; a dot-probe task then assessed biases in attention orienting. The social conditioning task modified subjective ratings of the neutral stimuli. Moreover, for the neutral stimulus that was paired with the aversive stimulus, the strength of conditioning showed a relationship with subsequent attentional vigilance. The findings elucidate mechanisms by which negative peer experiences during adolescence may affect emotional processing.     

The effects of short term flotation REST on relaxation: a controlled study

The purpose of this study was to compare the effects of restricted environmental stimulation using a flotation tank (Flotation REST) to the effects of a normal sensory environment on relaxation. All of the subjects were first introduced to a simple relaxation program to be used during the experimental sessions. The program consisted of guided point-to-point relaxation, breathing techniques, and visual imagery techniques. Subjects were then pre-tested on measurements of electromyogram (EMG), galvanic skin response (GSR), peripheral skin temperature, and systolic and diastolic blood pressure. The experimental group experienced ten 45-minute sessions practicing the relaxation program in a Flotation REST environment. The control subjects practiced the same relaxation program in a similar body position for 45 minutes in a normal sensory environment. All subjects answered a five-question Subjective Relaxation Questionnaire on trials five through ten and were then post-tested on EMG, GSR, skin temperature, and blood pressure. The results indicated significant differences between groups from pre-test to post-test on systolic and diastolic blood pressure; the experimental group showed greater reductions. Significant differences also were observed on three of five questions on the Subjective Relaxation Questionnaire; the experimental group reported greater subjective relaxation and trends in a similar direction on the remaining two questions. The results of this study indicate that flotation REST enhances point-to-point relaxation, breathing techniques, and visual imagery techniques and, when combined with these techniques, can be an effective means of teaching normal subjects to lower systolic and diastolic pressure and heighten their subjective perception of relaxation.     

Retention of orienting reaction habituation in chronic alcoholics

A polygraphic study on resistance to habituation of the somatic (EMG), autonomic (finger plethysmogram, galvanic skin reaction, respiration) and EEG (acoustic-evoked potential and EEG-blocking reaction) components of the orienting reaction, elicited by a repetitive auditory stimulus during successive (weekly) sessions was performed in 67 chronic alcoholics and in 70 matched normal subjects (control group). The study showed significant retention disturbances of orienting reaction habituation (i.e., of learning), or the “saving” of stimulations, achieved from one session to the other to obtain the habituation criterion, the savings being less in alcoholics than in control subjects. The severity of habituation retention disturbances depended on patients’ ages, types of alcoholism, alcohol consumption intensity and chronicity, as well as the type of resting EEG.     

Does upper-body elevation affect sleepiness and memories of hypnagogic images after short daytime naps?

The present study aimed to examine the effects of a somatosensory stimulus on sleepiness and memories of hypnagogic imagery during short daytime naps. Participants experienced two daytime nap conditions: (1) a somatosensory stimulus was created by raising the upper part of the bed 20 min after turning off the light and (2) a somatosensory stimulus was not created; the angle of the upper part of the bed remained flat. Approximately 20 min and 30 s after turning off the light, participants were awakened and questioned regarding their subjective sleepiness and the presence or absence of hypnagogic imagery. Results showed that subjective sleepiness following the nap was reduced only in the raised condition, and hypnagogic imagery in the raised condition was lower than that in the flat condition. These findings may provide insight on developing new techniques for improving subjective conditions after awakening.     

An automated system for administering continuous workload and for measuring sustained continuous performance

Sustained continuous performance for up to 42 h was studied with 60 male volunteers in two separate protocols. The recuperative value of six 1-h nap breaks and a single 6-h nap break were contrasted in 20 subjects, 10 in each nap group. Forty other subjects attempted to work continuously with no breaks for 42 h. Twenty of these subjects worked simultaneously on separate parallel computer-based tasks, but worked in the same room in pairs. All subjects in the two nap groups (N=10 and N=10), as well as 20 who had no scheduled breaks, worked alone, almost isolated, with minimal interaction with the experimenters. During each 10 min, subjects performed a tracking task, a pattern-memory task, and an addition task and provided subjective ratings on sleepiness and attention/fantasy. Results showed that computerized tasks demanding sustained continuous performance without naps cause more rapid performance deterioration than previously tested intermittent-work paradigms.