Kenneth Hugdahl

Acquisition of phobias and anxiety response patterns in clinical patients.

The ways in which phobic patients (N = 106; animal-, social- and claustrophobics) acquired their phobias were investigated in the present study. The results showed that a large majority (58%) of the patients attributed their phobias to conditioning experiences, while 17% recalled vicarious experiences, 10% instructions/information and 15% could not recall any specific onset circumstances. There was no clearcut relationship between the ways of acquisition and anxiety components (subjective, behavioral, physiological), nor did the conditioning and indirectly acquired phobias differ in severity. However, some interesting trends emerged in the data, showing that animal phobics who recalled conditioning experiences to a larger extent also responded physiologically. For patients with indirect onset experiences (for all three types of phobias) the reverse was true, i.e. they responded to a larger extent in a cognitive-subjective way, rather than with increased physiological arousal.

The three-systems-model of fear and emotion--a critical examination.

Abstract The ‘Three-Systems-Model’ of fear and emotion (Lang, 1968; Rachman. 1978b) is reviewed and discussed. The paper is centered on four topics relevant to such a view of fear; The definitional focus; Measurement and quantification of components; Implications for etiology; Implications for treatment of phobias. Definitional problems with the radical operationalist view implied by the Tree-Systems-Model are identified and discussed. In addition problems with measurement and quantification of the various components are discussed. Implications for etiology of phobic fears are noted. Finally, it is suggested that treatment methods be individually tailored to the particular component response-profile displayed by each patient, and that the identification of such a profile is included in standard behavioral diagnosis procedures when fear is clinically assessed.

Electrodermal conditioning to potentially phobic stimuli: Effects of instructed extinction

Abstract It was hypothesized that electrodermal responses to potentially phobic stimuli “conditioned” through verbal threats about an aversive UCS should be equally resistant to instructed extinction as the responses obtained by actual CS-UCS pairings. Two groups of human subjects were exposed to pictures of either snakes and spiders (phobic CSs), or circles and triangles (neutral CSs) in a differential Pavlovian conditioning paradigm. Changes in skin conductance were recorded. Half of the subjects in each group were threatened with a shock-UCS while the other half were given shock-reinforced CS presentations. At the onset of extinction, all subjects in each of the four groups were informed that no more UCSs were to be delivered, and the shock electrodes were removed. All groups showed evidence of conditioning during acquisition. During extinction there was an immediate drop in responding in the two neutral groups, whereas the two phobic groups showed reliable evidence of resistance to extinction, with no differences between the threatened- and the CS-UCS-group. The observed resistance to extinction found in the phobic groups implies a similarity to the irrationality of real-life phobias. Furthermore, the data are in accordance with analysis of electrodermal fear-conditioning as a case of prepared learning.

PREPAREDNESS AND AROUSABILITY AS DETERMINANTS OF ELECTRODERMAL CONDITIONING.

Abstract ‘Arousability’, as defined through spontaneous electrodermal responses, has been empirically linked to anxiety, phobic symptoms and outcome of systematic desensitization. Previous data from our laboratory indicate that ‘preparedness’, as defined through potentially phobic vs. fear-irrelevant or ‘neutral’ conditioned stimuh, is an important determinant of electrodermal conditioning. The present experiment compared groups selected to be high or low in spontaneous responding during differential conditioning to potentially phobic or neutral stimuh. It was found that the effects of these two factors were essentially additive, i.e. conditioning and resistance to extinction were better for phobic stimuli and for high-arousal groups. The high-aroused group with phobic stimuh showed diffuse responding during acquisition, not differentiating between reinforced and unreinforced cues. However, it was the only group that failed to extinguish during 20 trials, which indicates that high arousal gives superior resistance to extinction particularly for phobic stimuli.

Acquisition of agoraphobia, mode of onset and anxiety response patterns.

Abstract The ways in which 80 agoraphobic patients had acquired their phobia were investigated. The patients were requested to answer a questionnaire concerning: (a) the origin of the phobia, with items relevant for conditioning experiences, vicarious experiences and experiences of negative information/instruction; (b) physiological reactions; (c) anticipatory anxiety; (d) negative thoughts while in the phobic situation. In addition, data on mode of onset, precipitating factors, family history of phobias, marital and occupational status and severity of the phobia were obtained. The reported anxiety reaction was conceptualized in terms of the Three-Systems Model of fear and anxiety, i.e. anxiety as composed of a physiological, cognitive and behavioral component. The results showed that a large majority (81%) of the patients attributed their phobias to conditioning experiences, while 9% recalled vicarious learning, none recalled instruction/information and 10% could not recall any specific onset circumstances at all. In another classification 46% of the patients had a rapid, 36% a gradual and 18% a slow onset of their phobias. There was no relationship between either the ways of acquisition, or the modes of onset, and the anxiety components, nor did the conditioning and the indirect groups differ in severity of phobic reactions.

Biological vs experiential factors in phobic conditioning

Abstract The present study was performed as a test of phobic conditioning being a case of prepared learning (Seligman, 1971). Skin conductance responses were conditioned in three groups of subjects to either slides of snakes and spiders; electric outlets; or geometric shapes, as conditioned stimuli (CSs) with shock to the forearm as the unconditioned stimulus (UCS). The purpose of the experiment was to compare electrodermal conditioning to potentially phobic CSs, i.e. snakes and spiders, with conditioning to fear-relevant, but non-phobic, CSs, i.e. electric outlets. Each subject saw two pictures, either a snake or a spider; or two different slides of electric outlets; or two different geometric shapes. Only one of the two cues (the CS + ) was immediately followed by the shock-UCS during the acquisition phase. Thus, a differential paradigm was used. There were 4 habituation, 12 acquisition, and 16 extinction trials. The duration of the pictures was 8 sec with an intertrial interval of between 35–45 sec. The results showed reliable effects of conditioning in all three groups during the acquisition phase. Furthermore, a significant interaction during extinction is reported, indicating responses to potentially phobic CSs to be more resistant to extinction than responses to the other two classes of stimuli. It is concluded that the present results favor an interpretation of phobic conditioning in terms of biologically prepared learning.

Habituation of the electrodermal orienting reaction to potentially phobic and supposedly neutral stimuli in normal human subjects

Abstract Three experiments concerning habituation of the electrodermal orienting response to pictures of phobic and neutral objects in normal human subjects are reported. In the first one, two independent groups were given either 16 presentations of snake pictures, or 16 presentations of pictures of houses. The pictures differed between subjects but a certain subject saw the same pictures throughout the experiment. The results showed no significant difference between groups in response magnitude, but significantly fewer trials to habituation in the group given neutral pictures. The second experiment used a within-subject design, with mixed presentation of either a snake and a house picture, or a spider and house picture. The responses to phobic stimuli were larger than those to neutral ones, and the latter took significantly fewer trials to habituate. The third experiment used a between-subject design where some shocks were given before the experiment, and the subject was threatened that some shocks would also be given during the experiment. This procedure potentiated the difference between the stimuli, so that the responses to the phobic pictures were about four times as large as those to the neutral stimuli.

A dichotic listening study of differences in cerebral organization in dextral and sinistral subjects.

The purpose of the present study was to compare immediate recall of paired dichotic presentation of CV-syllables in a dextral and a sinistral group when considering both gender, familial sinistrality, and hand-posture during writing. Forty subjects (20 dextrals and 20 sinistrals) were given 306 presentations of the six Swedish stop-consonants paired with the vowels a, i, and u in a dichotic-listening test. The results showed significant differences between the two groups with fewer consonant-errors observed for the right ear input in the dextral group, and fewer consonant-errors in the left ear input in the sinistral group. Thus, a REA was demonstrated for the dextral group, and a LEA was demonstrated for the sinistral group. The results were most clear-cut for the consonants whereas vowels yielded insignificant differences. It is concluded that the present design allows for the separation of left- and right-hemisphere language dominance for right- and left-handed subjects.

Electrodermal conditioning to potentially phobic stimuli in male and female subjects

There are clear sex differences in incidence of phobias for small animals, and in questionnaire-measured fear for animals. The present study examined whether these sex differences were reflected also in electrodermal conditioning to potentially phobic stimuli. Separate groups of males and females were exposed to a conditioning session involving either potentially phobic, snakes and spiders, or fear-irrelevant, flowers and mushrooms, conditioned stimuli with electric shock as the unconditioned stimulus. A long interstimulus interval differential paradigm was used, allowing analysis of first- and second interval anticipatory responses, and third-interval omission responses. There were 8 habituation trials, 16 acquisition trials and 40 extinction trials. Half of the trials involved the reinforced cue, and the other half the unreinforced cue. There were clear conditioning effects, with superior acquisition and resistance to extinction to the phobic as compared to the fear-irrelevant stimuli. However, there were no differences between the two sexes. The results were interpreted in terms of the preparedness theory of phobias, and in terms of social learning factors.

Heart-Rate responses (HRR) to lateralized visual stimuli

Direction of changes in heart-rate responses (HRR) were investigated in three separate experiments as a measure of differential cognitive and emotional specialization of the cerebral hemispheres. Visual stimuli were presented via the visual half-field technique in all three experiments. Slides with different contents were flashed for 200 msec on each trial either to the left or right of a center LED fixation point. The LED went on 5 seconds prior to slide onset. HR changes were scored as second-by-second deviations during 10 seconds after LED onset from pre-LED base line. In the first experiment it was hypothesized that emotionally relevant stimuli initially projected to only the right hemisphere would result in more anticipatory acceleration than when the same stimulus was initially projected to the left hemisphere. A picture of a snake and of a geometric figure were repeatedly briefly flashed to the right of the LED for half of the subjects, and to the left for the other half. There were 25 trials with an intertriai interval of 25–40 seconds. Results showed significant effects of deceleration as a function of the slide stimulus in all groups on seconds 5, 6, or 7 after onset of the center LED. Furthermore, an anticipatory acceleration was observed during the first trial-block on seconds 3 and 4 in the right hemisphere groups only with no differences between the neutral and emotional stimuli. In Experiments 2 and 3, a letter-string of six letters and a complex symmetric pattern were used as stimuli. These stimuli were chosen because previous research has clearly implicated the hemispheres to be differentially specialized in their ability to process verbal and visuo-spatial stimuli. The set-up was identical to Experiment 1, with the exception that differences in response to the two types of stimuli were evaluated on a within-subjects basis. The results from Experiments 2 and 3 showed stimulus-related deceleration, peaking on seconds 5–7 in all groups and an anticipatory acceleration peaking on seconds 3 and 4 in the right hemisphere groups, with decelerations during the corresponding seconds in the left hemisphere groups. The results are discussed in relation to recent findings by Walker and Sandman (1982) about the possibility of hemispheric specialization in psychologic influences on heart rate changes in response to environmental demands.