Conditioned Orienting and Defensive Responses

Physiological responses were recorded while 9 females (Group P) who Feared spiders and 9 who did not (Group N) viewed “neutral” and spider slides in a delayed, differential conditioning procedure. Two different tones were the conditioned stimuli, and 12 neutral and 12 spider slides the unconditioned stimuli. Each CS was 11 sec long. Only Group P showed differential HR conditioning-anticipatory acceleration to the CS preceding the spider slides (CS+). For both groups, cephalic vasoconstriction was greater to the CS+ than to the CS-. However, with repeated trials Group P's response to the CS+ became more prolonged, so that by the last block of trials contraction persisted until the end of the CS period. Group N's response, on the other hand, continued to be constriction followed by rapid recovery to the prestimulus level. Although significant electrodermal conditioning did not occur, Group P tended to give larger anticipatory SC. responses to the CS+ than to the CS-. There was little evidence of somatic-autonomic coupling on a group basis. When considered along with post-experimental reports, the results indicate that at least some of the cardiovascular components of the defensive response (DR) are conditionable.     

Orienting and Defensive Reactions to Phobic and Conditioned Fear Stimuli in Phobics and Normals

The aim of this study was to compare cardiovascular and electrodermal responses from subjects conditioned to fear-relevant stimuli with responses from phobics selected to fear the same stimuli. In the first session of the conditioning group slides of either a snake or a spider were presented. One of these served as a CS+ reinforced by an electrical shock and the other as a CS-, which was never followed by shock. In addition the conditioning group was exposed to two neutral pictures (flowers and mushrooms). The phobic group viewed the same type of stimuli and were administered some electrical shocks uncorrelated with the slides. In the second session, randomly formed halves of each group were shown (a) slides of a spider and a snake, or (b) two neutral ones. There were reliable acquisition effects in the conditioning group with the CS+ evoking larger palmar than dorsal skin conductance responses (SCRs) whereas the reverse was true for the CS-. During extinction differential responding to CS+ and CS- was maintained but palmar/dorsal differentiation disappeared. In the phobic group, feared and non-feared cues elicited differential responding with larger palmar SCRs for the feared cue only. The conditioning group failed to evidence heart rate differentiation during acquisition when all heart rate responses (HRRs) were collapsed into a single trial block (TB). When HRRs were grouped into 2 TBs, responses shifted from deceleration to CS+ on TB1 to acceleration on TB2 whereas responses to CS- were unaffected. During extinction, HR exhibited deceleration to both cues but more to CS+ than to CS-. The phobic group's heart rate accelerated to the feared cue and decelerated to the unfeared cues in both sessions. There was no difference between groups' responses to neutral cues during the second session. The results partially validate a conditioning analogue for specific phobias and the inconsistent aspects are discussed in terms of different coping strategies.     

Cardiovascular Components of Orienting and Defensive Responses

Data from an earlier study of physiological responses to affective visual stimulation were reanalyzed in an attempt to delineate the cardiovascular components of the OR and the DR. A HR response profile to unpleasant stimulation was obtained for each of 49 S_s by computing his average beat-by-beat HR response to slides of homicide victims. A hierarchical grouping procedure was then used to group these profiles in terms of similarity. An optimum grouping of three distinct groups of profiles emerged. Group A consisted of 9 S_s whose HR responses were accelerative in nature, Group D of 12 S_s who gave marked decelerative responses, and Group MD of 28 S_s who gave moderate decelerative responses. The cephalic vasomotor response given by Grup A to the homicide slides was vasoconstriction, while the response of Groups D and MD was vasodilation. The results provide some support for the suggestion that the OR consists of HR deceleration and cephalic vasodilation, while the DR consists of HR cceleration and cephalic vasoconstriction. However, it is possible that these “classic” patterns of cardiovascular activity occur in only some S_s and only under certain conditions, and that they may be obscured by the use of undifferentiated group data.     

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.     

Autonomic Responses to Affective Visual Stimuli

Thirty-two subjects were categorized by an objective questionnaire as high or low in fear of mutilation. These subjects viewed six slides each from three categories: neutral, incongruous, and mutilation. As predicted, fearful subjects' cardiac responses to mutilation were acceleratory and their counterparts' deceleratory. Both groups reacted to incongruous stimuli with heart rate deceleration. Unexpectedly, both samples displayed cardiac acceleration to the neutral category. Respiratory patterns of initial expiration characterized low-fear subjects whereas inspiration was typical in the high-fear group. However, respiratory activity did not vary over slide types. The high-fear sample emitted electrodermal responses of greater amplitude and slower recovery to mutilation slides than to the other categories. In both respects, the high-fear sample exceeded their counterparts. Finally, fearful subjects exhibited a more pronounced tendency to judge mutilation slides more aversive than incongruous or neutral materials. In general, responses to mutilation materials indicated reactions of defense in fearful subjects and orientation in low-fear persons.     

Physiological Responses of Anxious and Normal Subjects to Simple Signal and Non-Signal Auditory Stimuli

In an attempt to assess orienting (OR) and defensive responses (DR) of anxious and normal Ss, heart rate (HR) and skin conductance (SC) changes were measured in response to three intensities of signal and non-signal tones. Anxious Ss significantly differed from normal Ss in the number of spontaneous SC responses emitted, but did not differ in either magnitude or rate of habituation of SC responses to the tones. An analysis of second-by-second changes in HR suggested that, relative to normal Ss, anxious Ss show a deficit in OR and a greater tendency to respond with a pattern characteristic of a DR. This difference was particularly apparent under signal conditions.     

The Elicitation and Habituation of Orienting and Defensive Responses to Phobic Imagery and the Incremental Stimulus Intensity Effect

Using imaginal stimuli, the present investigation examined psychophysiological responses to imagery and the roles of Groves and Thompson's (1970) dual process theory and Sokolov's (1963) model of the defensive response(DR) in mediating the incremental stimulus intensity effect (ISIE). Experiment I was undertaken to determine whether phobic and neutral imagery could be discriminated by DRs and orienting responses (ORs). In a within groups design. 19 analogue speech phobics were exposed to 4 neutral and 4 phobic scenes. Dependent measures were skin conductance measures and second-by-second heart rate (HR). The results showed that DRs occurred only in response to phobic scenes. In a between groups design. Experiment II compared an incremental series (IS) of 16 phobic imaginal stimulus presentations to a constant series. Subjects were analogue speech phobics with 14 subjects per condition. For both conditions the last 4 scene presentations were the same. Dependent measures were second-by-second HR, second-by-second cephalic pulse amplitude, and skin conductance measures. The results showed greater habituation in the IS condition, but were inconclusive with regard to the roles played by dual process theory and the DR model in the ISIE.     

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.     

Orienting in Schizophrenia: Habituation to Auditory Stimuli of Constant and Varying Intensity in Patients High and Low in Skin Conductance Responsivity

Groups of schizophrenics and normal controls were exposed to different series of tones of constant (80dB) and variable intensity (60, 80, and 100 dB). Measurements included bilateral skin conductance, finger pulse volume, and heart rate. Both groups were split on the common median in skin conductance response to constant intensity tones to form matched patient and control groups of low and high responsivity. The low and high responsive schizophrenic groups were more clearly separated than the two control groups in rate of spontaneous skin conductance fluctuations, skin conductance magnitudes, and skin conductance levels, primarily because of generalized hyperactivity in high responsive patients. This pattern was clearest for the most intense tone and left hand recordings. High responsive schizophrenics also showed larger response amplitudes, shorter rise and recovery times, and a smaller ratio of elicited to spontaneous responses, than high responsive controls. Finger pulse volume responses recorded from the left hand were smaller in the patient groups, whereas patients and controls did not differ in right hand recordings. High skin conductance responsive subjects showed more heart rate deceleration than low responsive subjects, and schizophrenics had more decelerative responses than controls.     

Orienting and Defensive Responding in the Electrodermal System: Palmar-Dorsal Differences and Recovery Rate during Conditioning to Potentially Phobic Stimuli

It was suggested that the effects of fear-relevant pictures as conditioned stimuli (CSs) for electrodermal responses may be explained if it is assumed that they produce conditioned defense responses (DRs), as opposed to the orienting responses (ORs) that are produced by fear-irrelevant stimuli. Some propositions in Edelberg's theory of electrodermal activity were used to differentiate between DRs and ORs in a test of this hypothesis. Groups of subjects were conditioned to fear-relevant (snakes and spiders) or fear-irrelevant (flowers and mushrooms) CSs by means of an aversive (electric shock) or a non-aversive (imperative signal for a reaction time (RT) task) unconditioned stimulus in long interval differential paradigms. The neutral-shock, phobic-RT, and neutral-RT groups showed no palmar-dorsal differences either in magnitude, probability or amplitude, and no conditioning in the recovery rate measure. However, the phobic-shock group showed a peak of dorsal magnitude early in training that subsequently habituated whereas the palmar magnitude data indicated a gradual conditioning effect that lasted throughout the 20 extinction trials. In addition, it showed slower recovery to the reinforced than to the nonreinforced stimulus. These data are taken as support for the hypothesis.     

Factor Analytically Derived Components of Orienting, Defensive, and Conditioned Behavior in Electrodermal Conditioning

The hypothesis that conditioned electrodermal responses can be analyzed into separate components of orienting and conditioned behavior was tested with a factor analytical method. Multiple responses from 105 Ss in a long interstimulus interval paradigm were grouped into four blocks of 6 trials each, and a correlation matrix computed from intercorrelations between different multiple responses during four stages of training. The first analysis was performed on the CS, pre-US, and post-US responses, and resulted in three significant factors. The first one was defined by the CS response early in training and was interpreted as reflecting orienting behavior. The second factor was defined by the pre-US response late in training and was interpreted as representing expectancy or preparatory processes. The third factor tentatively was designated as a conditioned response factor of defensive nature, since it was defined by the post-US response late in training. This interpretation was confirmed in a second analysis which included the UR. Essentially, the factor structure from the first analysis was replicated, with the UR highly loaded in the third factor, which therefore was interpreted as reflecting defensive behavior.     

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.     

Cardiovascular and Electrodermal Responses Conditioned to Fear-Relevant Stimuli

This study examined heart rate, finger pulse volume, and skin conductance responses in subjects conditioned to fear-relevant (snakes and spiders) and fear-irrelevant (flowers and mushrooms) slide stimuli by an electric shock unconditioned stimulus. A differential conditioning paradigm with an interstimulus interval of 8 sec was used. There were 4 habituation, 8 acquisition, and 20 extinction trials with each of the two cues. The results demonstrated reliable acquisition for finger pulse volume and skin conductance responses, with superior resistance to extinction for the fear-relevant conditioned stimuli. The heart rate data showed no differentiation between reinforced and nonreinforced cues during acquisition and extinction, and no effect of fear-relevance. This discrepancy between skin conductance and finger pulse volume responses, on the one hand, and heart rate, on the other, was interpreted as due to differences in innervation, with the former measures mainly reflecting sympathetic and the latter parasympathetic effects.     

Effects of Length of Training and Amount of Tone Frequency Change on Amplitude of Autonomic Components of the Orienting Response

The present study investigated amplitude of the skin conductance response (SCR), heart rate response (HRR), and linger pulse volume (FPV) response components of the orienting response to a change in lone frequency following habituation training. Experimental subjects received either 5 or 20 presentations of a 1000 Hz, 70 dB training stimulus of 3 sec duration followed by presentation of a test stimulus. Half of these subjects received a test stimulus of 670 Hz (decrease of 250 mels), while for the other half, the test stimulus was a 380 Hz (decrease of 500 mels) tone. Two independent control groups received 6 and 21 presentations of the training stimulus respectively. This resulted in a 3 × 2 factorial design (N = 90). The results indicated that test trial SCR amplitude was significantly larger in experimental groups than in control groups and that larger responses occurred for a change of 500 mels than for one of 250 mels. Experimental groups also displayed significantly larger HRRs than did control groups, but within (he experimental groups, response amplitude was not influenced by amount of change. Length of training had no significant effect on either SCR or HRR amplitude on the test trial. For digital vasoconstriction, experimental groups displayed significantly larger FPV responses than did the control groups only after 2(1 training trials, and response amplitude was not influenced by amount of stimulus change.     

Sensation Seeking and Psychophysiological Responses to Auditory Stimulation

This study tested the hypothesis that the orienting response (OR) is one of the biological correlates of sensation seeking. Skin conductance (SC), heart rate (HR), and peripheral vasomotor (VM) activity were recorded while ten 60dB, 1000 Hz, slow-rise-time tones were presented to male subjects with high (N = 16) and low (N = 15) total scores on Form V of the Sensation Seeking Scale (SSS). There were no significant differences between groups in the SC or VM responses to the first (novel) tone or in the rate at which these responses habituated. The HR response to the first tone was deceleration (an OR) for the high SS group (as well as for a high Disinhibition subgroup), while the response of the low SS group (and a low Disinhibition subgroup) included what appeared to be startle components—a short-latency accelerative response that habituated rapidly on subsequent trials. It is suggested that individuals with low sensation seeking tendencies may be unusually prone to startle, and that subsequent research on the biological correlates of sensation seeking should take into account individual differences in the tendency to give orienting, defensive, and startle responses.     

Habituation of the Orienting Response in Sleep

This experiment was designed with stimulus parameters deliberately chosen to maximize the probability of observing habituation of the orienting response (OR) in sleep: weak stimulus, short interstimulas interval. with test for both dishabituation and spontaneous recovery, Habituation of finger plethysmograph. heart rate, skin potential. and skin resistance responses was studied in delta sleep and RKM sleep in 46 male undergraduate volunteers. There was significant habituation of both finger plethysmograph and heart rate responses in both delta and REM sleep, as well as dishabituation and spontaneous recovery. None of these effects was observed in the electrodermal measures. Results were compared with other studies of habituation of the OR in sleep, as well as theories of habituation. The authors do not interpret the results as demonstrating learning during steep.     

Stimulus Site Effects on Skin Conductance Responses From the Volar Surfaces

Pulse trains were applied separately to each forefinger and to each hallux of 23 Ss to assess stimulus site effects on the relative amplitudes of skin conductance responses recorded concurrently from each palm and from each plantar surface. A binaurally presented tone was used as a non-lateralized stimulus. Analyses of the ratio of response amplitudes from contralateral recording sites indicated that for both the upper and lower extremities, responses from the volar surface of the stimulated extremity were augmented in amplitude. Responses from the volar surface of the extremity ipsilateral to the stimulus and recording sites involved the same extremity. Analyses of the ratio of response amplitudes from the palmar and plantar surfaces on the same side of the body indicated that the specific effects of stimulation did not cross the body midline. The results were interpreted as indicating a regionally differentiated sympathetic outflow to the volar sweat glands that reflects the locus of cutaneous stimulation.     

Interactions of Marijuana and Induced Stress: Forearm Blood Flow, Heart Rate, and Skin Conductance

To examine the interaction of marijuana and an induced state of stress, on both subjective and physiological measures, two groups of 15 subjects each were given a mental arithmetic task to perform. The sequence of events was 10 min each of pre-stress, stress, post-stress, intoxication (about 20 min), pre-stress, stress, post-stress. In the intoxication phase, one group smoked marijuana containing 14 mg Δ⁹-THC while the other group smoked a placebo. The dependent variables were forearm blood flow (FBF), heart rate (HR). and skin conductance (SC), and a subjective measure of stress–the Multiple Affect Adjective Checklist (MAACL). The results revealed all physiological variables to be reactive to the stress task. In addition, marijuana intoxication produced reliable increases in both pre-stress HR and FBF, and yet the physiological response to the post-intoxication stress period showed no significant decrement when compared In the placebo group. Discussion of these results centered around marijuana's effects on tonic and phasic reactivity.     

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.