اجتناب از حالات صورت عاطفی در اضطراب اجتماعی: رویکرد اجتناب وظیفه

The Approach–Avoidance Task (AAT) was employed to indirectly investigate avoidance reactions to stimuli of potential social threat. Forty-three highly socially anxious individuals (HSAs) and 43 non-anxious controls (NACs) reacted to pictures of emotional facial expressions (angry, neutral, or smiling) or to control pictures (puzzles) by pulling a joystick towards themselves (approach) versus pushing it away from themselves (avoidance). HSAs showed stronger avoidance tendencies than NACs for smiling as well as angry faces, whereas no group differences were found for neutral faces and puzzles. In contrast, valence ratings of the emotional facial expressions did not differ between groups. A critical discrepancy between direct and indirect measures was observed for smiling faces: HSAs evaluated them positively, but reacted to them with avoidance.

Social phobia (social anxiety disorder, SAD) is a common and debilitating disorder, characterized by marked and persistent fear of one or more social and performance situations in which the person is exposed to unfamiliar people or to possible scrutiny by others (American Psychiatric Association, 1994). Psychological models of social phobia emphasize the importance of cognitive factors for the etiology and maintenance of the disorder (Beck & Emery, 1985; Clark & Wells, 1995; Foa & Kozak, 1986; Rapee & Heimberg, 1997). Several authors have argued that social phobia is maintained by highly specific dysfunctional beliefs (e.g., Beck & Emery, 1985), which refer to negative self-evaluation (Stopa & Clark, 1993). Beliefs that facilitate the interpretation of social situations as threatening may lead to the extensive fear of being negatively evaluated. Consequently, social situations are avoided, or are endured with intense anxiety or distress (American Psychiatric Association, 1994). Rapee and Heimberg (1997) integrated avoidance into their cognitive–behavioral model of the maintenance of social anxiety. They assume that confronted with a situation of possible threat, socially anxious individuals’ dysfunctional beliefs activate cognitive (dysfunctional thoughts), physical (physiological arousal), and behavioral (overt avoidance) symptoms of anxiety. Anxious individuals continually scan the environment for signs of impending negative evaluation. If escape is impossible, they endure the situation, and they may engage in more subtle behavioral strategies with the intention to prevent possible negative evaluation from others (Wells et al., 1995). These strategies may become manifest in reduction of conversational participation and eye contact, aimed at drawing attention away from oneself and decreasing the risk of criticism. Avoidance of or within social situations acts as an important maintaining factor of social phobia, because it prevents effective processing of the situation and disconfirmation of negative beliefs (Turk, Lerner, Heimberg, & Rapee, 2001). However, it is difficult for therapists and researchers to sufficiently inquire about avoidance strategies by directly asking anxious individuals, because not all elements of fear are accessible to introspection (Foa & Kozak, 1986). In some cases, in-situation safety behavior cannot easily be observed because it appears habitually and fast. Nevertheless, these behavioral aspects of social anxiety are a central component of cognitive–behavioral therapy (CBT), which is the most efficient psychological intervention for SAD (Hofmann & Barlow, 2002). For the effectiveness of exposure training, it is important that patients pay full attention to the feared situation, including non-verbal social references (Foa & Kozak, 1986). For example, Wells and Papageorgiou (1998) could show that instructions to maintain the focus of attention on the feared situation increased the efficacy of exposure techniques. Avoidance behaviors have been studied in several different ways. The most straightforward way is to ask highly socially anxious individuals (HSAs) about their reaction, as in the avoidance scale of the Liebowitz Social Anxiety Scale (LSAS; Liebowitz, 1987; Mennin et al., 2002; Oakman, Van Ameringen, Mancini, & Farvolden, 2003). Questionnaires, however, are prone to self-presentation strategies, demand characteristics, and distortions based on social desirability. Moreover, they tend to address many different social situations without focusing on the processing of facial expressions, which are especially relevant to the socially anxious, because they are a major source of information in social interactions, conveying feedback about other people's reactions (Planalp, DeFrancisco, & Rutherford, 1996). Experimental approaches to assess attentional biases for facial expressions in social anxiety support the occurrence of attentional avoidance to some extent. Using a visual probe task, Mansell, Clark, Ehlers, and Chen (1999) could demonstrate that socially anxious individuals showed avoidance of positive as well as negative emotional faces. Chen, Ehlers, Clark, and Mansell (2002), who used the same paradigm, found greater avoidance of negative, positive, and neutral faces than neutral household objects in patients with social phobia, compared with non-anxious controls (NACs). In contrast, using a modified dot probe task with facial stimuli, Mogg, Philippot, and Bradley (2004) failed to find avoidance of angry, happy, or neutral faces. Several methodological differences between the studies, such as different facial and control stimuli, may be responsible for the inconsistent results. Furthermore, to reconcile the discrepant findings, a limitation of the visual probe task has to be mentioned: Mogg and Bradley (1998) suggested that anxious individuals show an unstable attentional response pattern, which might be difficult to assess with this task, using only one or two different stimulus exposure durations. For this reason, monitoring of eye movements during attentional tasks seems to be a more appropriate measure (Rinck, Reinecke, Ellwart, Heuer, & Becker, 2005). Since it is the eyes in particular that signal social threat in facial expressions (Öhman, 1986), in a feared social situation, SAs tend to avoid looking at other people, especially at their eyes. Empirical confirmation for this observation comes from a study by Horley, Williams, Gonsalvez, and Gordon (2004). Using an experimental approach, the authors recorded eye movements and fixations of HSAs while they looked at pictures of angry, sad, happy, and neutral faces. They found that compared with NACs, HSAs avoided salient facial features, particularly the eyes in angry faces, and fixated non-salient features instead. Results support the clinical view that HSAs avoid emotionally relevant facial features because of their potential threat value. The results argue against a general avoidance of non-verbal social stimuli in SAs; instead they support the view that SAs avoid facial expressions or facial features, because they fear the potential threat contained in faces. However, eye movements and fixations, as measured by Horley et al. (2004), are limited because to a large extent, they reflect controlled aspects of avoidance behavior. Recent research has shown that additional information about the more automatic processing of threatening stimuli can be gained from using so-called indirect measures (see De Houwer, 2006). These tasks aim to infer the individuals’ attitudes towards potentially threatening objects without asking them directly. Thus, indirect measures are expected to be less affected by distortions created by social desirability than direct self-report measures (De Houwer, 2006). Moreover, self-report measures depend on awareness of the processes reported; therefore they mainly assess beliefs and behaviors that are easily accessed. For the study of cognitive structures that are not sufficiently accessible to conscious self-report, indirect measures are needed. Finally, they have been found to predict more automatic aspects of behavior, while direct measures are better suited for the prediction of more controlled behavior (Huijding & de Jong, 2006). Indirect measures have already been used successfully to study the cognitive aspects of anxiety and different anxiety disorders. The common principle of these reaction time tasks is that the participants’ response speed in a categorization task is affected by the compatibility between the response and the valence of the stimuli (De Houwer, 2006). In clinical psychology, indirect reaction time tasks have been used most often to study fears and phobias (e.g. Ellwart, Becker, & Rinck, 2005; Ellwart, Rinck, & Becker, 2006; Huijding & de Jong, 2006). A limitation of these tasks is that by assessing automatic associations, they mainly tap onto the semantic aspect of emotional information processing (Rinck & Becker, 2007), while emotional reactions consist of a complex pattern of responses. This is particularly relevant in fear and anxiety (Lang, Bradley, & Cuthbert, 1997), because they activate cognitive representations, physiological reactions, and a behavioral tendency to avoid the threatening stimuli. The indirect tasks described above, however, tell us little about behavioral responses, namely whether HSAs differ from NACs in their avoidance reactions. Therefore, we employed a task recently introduced by Rinck and Becker (2007), the Approach–Avoidance Task (AAT). The AAT is based on the finding that stimulus valence is linked to the psychological dimension of approach and avoidance. Approach and avoidance are basic responses associated with the primary motive systems of the brain that underlie every complex emotional responding (Lang et al., 1997). In particular, pleasant stimuli produce immediate approach tendencies, whereas negative stimuli produce immediate avoidance tendencies (e.g., Chen & Bargh, 1999). In fact, Darwin (1872) already suggested that our intentions and movements like pushing an object away or pulling it towards us are strongly associated with each other. He concluded that “if we eagerly wish an object to move in any direction, we can hardly avoid moving our bodies in the same direction, although we may be perfectly aware that this can have no influence” (Darwin, 1872, p. 64). One way to observe these approach–avoidance reactions in overt behavior is by means of arm movements. Several studies (e.g., Chen & Bargh, 1999; Solarz, 1960) have shown that avoidance is associated with pushing objects away from oneself, and approach is associated with pulling the objects closer. Most relevant here, Marsh, Ambady, and Kleck (2005) used this relationship to study behavioral responses to facial expressions in an unselected sample of students. They found that angry facial expressions facilitated avoidance-related behavior in their participants, that is, they responded more quickly by pushing a joystick away from themselves than by pulling it closer. Rinck and Becker (2007) adapted the AAT to the study of approach–avoidance responses in spider phobics in a series of experiments. An improvement of their AAT was the introduction of a “zooming” function: When participants push the joystick away from themselves in response to a picture presented on the computer screen, the picture shrinks. When the joystick is pulled, the picture grows until it almost fills the screen. This zooming effect creates the visual impression that the pictures are coming closer upon pulling of the joystick and that they move away upon pushing it. The zoom feature is particularly important because Experiment 2 by Rinck and Becker (2007) revealed that a fixed-size version of the AAT is open to cognitive re-interpretation of arm movements with reference to the stimuli versus to the body, which could lead to opposing effects. For this reason, the zoom feature was developed by the authors and tested in Experiments 3 and 4. Their results suggest that the zoom version of the AAT is resistant against cognitive re-interpretations of arm movements: pushing and pulling clearly mean avoidance and approach, respectively. Using this improved AAT, Rinck and Becker (2007) found a behavioral avoidance tendency in people afraid of spiders. Compared with NACs, they responded more quickly to spider pictures by pushing them away than by pulling them closer. Following Rinck and Becker (2007) and Marsh et al. (2005), we chose to use the AAT in order to investigate HSAs’ behavioral tendencies of approach and avoidance. In the experiment reported below, participants (HSAs and NACs) responded to pictures of emotional facial expressions (angry, neutral, or smiling) or to control pictures (puzzles) by pulling a joystick towards themselves (approach) or by pushing it away from themselves (avoidance). Upon pulling or pushing, the faces grew or shrank in size, respectively. When the joystick was moved all the way into one or the other direction, the picture disappeared from the screen, the response time was recorded, and the next picture was presented. In this task, the effects of facial expressions on approach and avoidance behavior were measured indirectly because the participants did not push or pull the joystick based on the depicted emotion. Instead, they responded to a different dimension by pulling all faces and pushing all puzzles (or vice versa), with no reference to emotional expressions at all. Because of this indirect measurement, the task should be more appropriate for measuring automatic behavioral responses than direct measures. In order to assess whether the behavioral responses observed in the AAT were associated with explicit evaluations of the emotional faces, we also asked the participants to rate the emotional valence of each picture presented during the AAT. Studies that examined explicit evaluative biases in social anxiety indicate that social phobia is not characterized by such a bias for non-verbal social information, that is, facial expressions (Merckelbach, van den Hout, van den Hout, & Mersch, 1989). Consequently, we hypothesized that HSAs and NACs would not differ in their direct valence ratings: both groups should evaluate angry faces as unpleasant, neutral ones as neutral, and smiling ones as pleasant. Regarding the response times in the AAT, however, the two groups were expected to differ. Following Marsh et al. (2005), we predicted an evolutionary-based avoidance tendency for angry faces in both groups, reflected by faster pushing than pulling by HSAs and NACs. Presumably, this RT difference should be stronger in HSAs, given that angry faces are more threatening to them. For smiling faces, there are two conceivable results. First, one might expect an approach tendency in both groups, because smiling faces are a signal of social acceptance and successful interaction. Contradictory to this expectation, however, smiling faces usually announce the initiation of an interaction, which is a threatening situation that socially anxious individuals try to avoid (Rapee & Heimberg, 1997). Consequently, it might be easier for them to push smiling faces away than to pull them closer. The latter prediction implies a discrepancy between direct and indirect measures: HSAs should give positive ratings of smiling faces, whereas their AAT effects should be negative (i.e., faster pushing than pulling). In clinical populations such as HSAs, previous research has not yet addressed the possible discrepancy of more controlled versus more automatic aspects of behavior. Finally, neutral faces and control stimuli should be of no affective valence for NACs, reflected by pull–push differences close to zero. As these stimuli contain no emotionally relevant information, the same expectation holds for HSAs.