The influence of anxiety on electrodermal responses to distractors
Introduction
While anxiety is classically thought to be associated with autonomic sympathetic activation (Lindsley, 1951, Claridge, 1967), negative findings with electrodermal activity (EDA), a sympathetic measure, are numerous. Furthermore, at first glance there are apparently paradoxical results. Both tonic and phasic EDA have been observed repeatedly to be reduced in high-trait anxious individuals (e.g. Wilson and Dykman, 1960, Naveteur and Freixa i Baqué, 1987, Naveteur and Roy, 1990, Wilken et al., 2000). Even pathologically anxious patients sometimes have initially smaller electrodermal responses than controls, although this is often combined with a subsequent slower habituation in patients (e.g. Lader and Wing, 1964, Hoehn-Saric et al., 1989, Hoehn-Saric et al., 1991, Hoehn-Saric et al., 1995, Hermann et al., 2002).
Coping abilities underpin several explanations for these findings. On the one hand Hoehn-Saric and McLeod (2000) related reduced sympathetic involvement to coping disorganisation or defensiveness. However, there is no a priori reason to consider reduced autonomic activation as the outcome of maladaptive coping, for surely the ability to lessen reactivity would appear to be an enviable skill for most anxious people. Accordingly reduced EDA could indicate successful coping. In fact Gilbert and Gilbert (1991) related chaotic and ineffective active coping to heightened rather than reduced sympathetic nervous activation, the latter they related instead to passive coping. Although passive coping is often described as maladaptive, some forms such as psychological and behavioural disengagement from a situation, can sometimes be a successful strategy.
Many tasks requiring sustained attention can be performed better if reactivity to distractors is inhibited. This is particularly relevant when distractors can potentially induce an emotional reaction. Habituation of the orienting response (OR) is thought to signify avoidance of attention to environmental stimuli (Waters et al., 1977), and active task engagement usually slows habituation of electrodermal responses (EDR) to irrelevant stimuli (Frith and Allen, 1983, Kroese and Siddle, 1983). Furthermore Kroese and Siddle (1983) convincingly argued, following information processing models of OR habituation (Öhman, 1979), that an internal representation of the eliciting stimuli is necessary for OR habituation, and this requires processing resources. Accordingly habituation to task-irrelevant stimuli may be delayed because resources are mainly allocated to the task rather than to the irrelevant stimuli. For the above reasons reduced electrodermal responding to distractors may reflect successful active coping.
Here high- and low-trait anxious participants were invited to perform a rather easy visual search task which nonetheless required continuous attentional monitoring. Auditory neutral and emotional words acted as distractors during the task. Particular care was given to reduce the situational stress. Indeed, due to their sensitivity to failure or loss of self-esteem (Spielberger, 1972), anxious individuals could use disorganised coping if they detected such a kind of threat. It was anticipated that compared with low anxious participants the high anxious participants would present smaller skin conductance responses (SCRs) to the distractors, or at least faster habituation. The reactivity to the emotional distractors, which are potentially deleterious for task performance, was expected to be specifically reduced in the high-trait anxious participants. To ensure that the involvement in the task was responsible for the differences between high- and low-trait anxious participants, both groups were compared not only during the task but also in a control condition (words delivered alone, no task to perform). Therefore, the expected effects were interactions involving at least, trait anxiety and conditions (task vs control).
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Participants
Thirty-three females between the ages of 17 and 21 participated. There were 17 high-trait anxious participants, and 16 low-trait anxious participants. They were selected from a pool of Biology and Sociology students from the University of Lille I based on their trait-anxiety scores as assessed by the self-analysis form of Cattell (1957). Low trait anxiety was defined as a decile score lower than 3. High trait anxiety was defined as a decile score higher than 7. Two additional participants were
State-anxiety scores
A 2 (Trait anxiety: low, high)×2 (Phase order: control-task, task-control) ANOVA was performed. Only the main effect of Trait anxiety was significant [F(1,29)=8.18; P<.01]: the high-trait anxious participants experienced a greater state anxiety (29.53, SD=13.16; maximum possible value: 70) than did the low-trait anxious participants (17.00, SD=3.86).
Rating scores of the visual search task difficulty
A 2 (Trait anxiety: low, high)×2 (Phase order: control-task, task-control) ANOVA was performed. The main effect of Trait anxiety was significant [F
Discussion
Our results provided evidence in support of reduced electrodermal reactivity in high compared with low anxious individuals. Firstly, through examination of response to emotional vs neutral distractors, overall SCRs were higher during the task than during the control condition. But as shown in Fig. 1, in the high-trait anxious participants the increase in SCR magnitude induced by the task was smaller following emotional distractors than following neutral distractors, such that responses to
Acknowledgements
The authors thank all participants for their co-operation. We are also grateful to V. Annoussamy, A. Bous, Dr H. Bouwalerh, and Pr. H. Sequeira who have all, in different capacities, helped us.
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