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Threat is in the eye of the beholder: Social anxiety and the interpretation of ambiguous facial expressions
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Behaviour Research and Therapy 45 (2007) 839–847 www.elsevier.com/locate/brat
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Threat is in the eye of the beholder: Social anxiety and the interpretation of ambiguous facial expressions K. Lira Yoona,, Richard E. Zinbarga,b a
Department of Psychology, Northwestern University, 2029 Sheridan Road, Evanston, IL 60208, USA The Family Institute at Northwestern University, Bette D. Harris Center, 618 Library Pl, Evanston, IL 60201, USA
b
Received 23 September 2005; received in revised form 24 April 2006; accepted 2 May 2006
Abstract The current study investigated the tendency of individuals with high levels of social anxiety to interpret ambiguous facial expressions in a threatening manner. Results obtained from self-report measures were consistent with previous studies in which highly socially anxious individuals endorsed threatening interpretations for ambiguous social information. More importantly, highly socially anxious participants showed relative facilitation of processing of threatening faces following neutral faces when a priming technique was used to eliminate artifact due to response selection bias. These findings support the hypothesized social anxiety-linked interpretive bias. r 2006 Elsevier Ltd. All rights reserved. Keywords: Social anxiety; Interpretive bias; Neutral face
Introduction Researchers have suggested that social anxiety is associated with a tendency to interpret ambiguous social events in a negative manner (e.g., Clark & Wells, 1995). Indeed, studies have shown that social phobics tend to endorse a negative interpretation for ambiguous social scenarios even when a positive interpretation was available (e.g., Amir, Foa, & Coles, 1998; Stopa & Clark, 2000). The basic fear in social phobia is about being negatively evaluated by others (APA, 1994). Since facial expression is an important way of conveying evaluation, pictures of human faces would be somewhat ecologically valid stimuli for research on disambiguation bias related to social anxiety. Of particular note, an image of a face is not the same as a person with whom we are interacting and, thus, it might not be the case that such images are more ecologically valid than linguistic stimuli. An important question, however, is whether the cognitive mechanisms that bias the processing of verbal stimuli among anxious individuals bias the processing of non-verbal stimuli as well. Recent studies have been using emotional facial expressions to test for cognitive biases in socially anxious individuals (e.g., Philippot & Douilliez, 2005), and results are mixed in terms of supporting the hypothesis. Corresponding author. Department of Psychology, University of Miami, P.O. Box 248185, Coral Gables, FL 33124-0751, USA. Tel.: +1 847 877 0501; fax: +1 847 491 7859. E-mail address: [email protected] (K. Lira Yoon).
0005-7967/$ - see front matter r 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.brat.2006.05.004
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For example, socially anxious individuals, when asked to identify the affect (negative vs. neutral) in briefly presented slides of faces, had a significantly lower criterion for identifying negative emotions than the nonanxious group, resulting in a bias towards identifying others’ emotional expressions as negative (Winton, Clark, & Edelmann, 1995). A more recent study, however, did not find any group differences between participants with generalized social phobia, anxiety disorders other than social phobia, and controls with regard to decoding accuracy or attributed emotion intensity to pictures of faces (Philippot & Douilliez, 2005). As MacLeod and Cohen (1993) argued about self-report studies, ‘‘the methodologies used [in the previous studies] have commonly introduced the possibility of experimenter demand effects and have made it impossible to dissociate a genuine interpretative bias from possible response selection bias effects’’ (p. 238). Indeed, because some previous studies (e.g., Amir et al., 1998; Philippot & Douilliez, 2005; Winton et al., 1995) relied solely on self-reports, it is difficult to rule out possible response selection bias. That is, the results from previous studies might reflect a greater tendency among socially anxious individuals to select the negative response option (i.e., response selection bias) rather than genuine on-line interpretive bias. A few studies have been conducted to address response selection bias when studying interpretive bias. For example, MacLeod and Cohen (1993) focused on comprehension latencies for individual sentences to eliminate response selection bias effects and study on-line interpretations. In their study, the first ambiguous sentence of each pair was followed by another sentence that represented a possible continuation of either the threatening or the benign/neutral interpretation of the original sentence. In addition, the first sentence was presented under any one of the three cue conditions designed to impose either a threat or neutral interpretation on this initial sentence or leave it fully ambiguous. The interpretation of the first sentence of each pair was assessed by examining the relative facilitation in reading the threat continuation compared with the neutral continuation. In the fully ambiguous condition, participants high in trait anxiety were indeed faster in reading threat continuations compared with the neutral continuations, whereas participants low in trait anxiety showed the opposite pattern. These results indicate that high trait anxious individuals selectively imposed threatening interpretations on the ambiguous sentences, while low trait anxious individuals selectively imposed non-threatening interpretations on the ambiguous sentences. Whereas there is evidence supporting genuine negative interpretive bias in trait anxiety (MacLeod & Cohen, 1993; Richards & French, 1992) and a lack of positive interpretive bias in social phobia (Hirsch & Mathews, 2000) with linguistic stimuli, as noted above it is still an open question whether the conclusions from these studies generalize to the processing of pictorial stimuli. Therefore, the present study aimed to examine whether socially anxious individuals interpret neutral facial expression in a more threatening manner than do less socially anxious people while eliminating response selection bias as an alternative explanation. We adapted the paradigm developed by MacLeod and Cohen (1993), and used pictures of angry and disgust faces as threatening stimuli. Pictures of disgust faces were included as threatening stimuli, because ‘‘disgust is a rejection-from-self-emotion’’ (Rozin, Lowery, & Ebert, 1994, p. 871). That is, humans reject disgust elicitors from the self (Rozin et al., 1994) and, thus, facial expression of disgust with a straight eye gaze implies aversion to the elicitor (in this case, the participant). Considering that fear of rejection or receiving a ‘‘You are not wanted’’ message is a core concern of social phobics (APA, 1994), we thought it was appropriate to include disgust faces as threatening to examine if socially anxious individuals interpret ambiguous faces not only as expressing anger but also disgust. We used pictures of faces that Ekman and Friesen (1976) classified as neutral to access participants’ interpretations of ambiguous social cues. In particular, we selected those pictures for which sizable minorities of the participants in Ekman and Friesen’s norming study gave alternative labels (such as anger or disgust) besides ‘‘neutral.’’ Because Ekman and Friesen’s neutral faces tend to be interpreted in different ways by different people, these faces serve the purpose of ambiguous stimuli in the current studies. A priming paradigm was used to rule out experimenter demand and response selection bias in explaining the differences between high and low socially anxious individuals’ endorsement of threatening interpretation of pictures of neutral facial expressions. The basic procedure in the current study involved presenting a cue picture of a face followed by a target picture of a face. Participants were instructed to press a response button as soon as they figured out what the facial expression depicted by each picture was. Importantly, the participant’s response did not indicate the content of his or her interpretation but rather just provided an index of his or her latency to reach an interpretation. The reaction times (RT) for the target (i.e., the second
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picture in each pair) should be influenced by the interpretation that a participant originally had imposed on the cue (i.e., the first picture in each pair). In other words, targets consistent with the interpretation imposed on the preceding cue should be primed more and, thus, lead to a faster RT than targets inconsistent with the preceding cue (an assumption that we tested as reported below). Accordingly, if a participant interprets pictures of neutral faces in a threatening way, then his/her RT to a target face representing threat (i.e., angry and disgust) should be speeded up following a neutral cue. Therefore, we predicted that highly socially anxious individuals would show faster latencies than low anxious participants to threatening target faces following neutral faces, indicating the presence of negative interpretive bias for neutral faces. If, however, highly socially anxious individuals do not have a marked negative interpretation style, but rather show a less positive interpretation style than low anxious participants, we expected that low socially anxious individuals would show faster latencies than highly anxious participants to happy target faces following neutral faces. Method Participants The participants were 51 undergraduates randomly selected from the Northwestern University introductory psychology class. Participants’ social anxiety level was assessed based on their scores on the 13-item selfconsciousness subscale of the Social Phobia Scale (SPS; Mattick & Clarke, 1998).1 This subscale has strong internal consistency (a ¼ .92) and construct validity, and is more factorially homogeneous than the full SPS (see Zinbarg & Barlow, 1996 for more information). Materials Stimulus picture sets Sixty picture sets were used in this experiment. Each set included two pictures, one picture serving as a cue and the other as a target. There were five different cues: a string of three question marks, a picture of an angry face, a disgust face, a happy face, and a neutral face. There were three different targets: a picture of an angry face, a disgust face, and a happy face. Thus, there were 15 different types of pairs. All these pictures were obtained from Ekman and Friesen’s (1976) Pictures of Facial Affect; all 14 posers appeared six to nine times throughout. There were no restrictions in terms of pairing cue and target faces except that the same person was never used as a cue and a target in the same trial. There were four blocks of trials, each of which consisted of 15 different types of pairs. The trials were presented in a different block randomized order for each participant. Procedure Participants were tested individually and told that the study was concerned with the effects of self-focused speeches on speech performance and on the processing of facial stimuli. The participant was then given a packet, which contained the 13-item shortened version of the SPS. Then, participants in the ‘‘speech’’ condition were asked to write a speech for 5 min, and they were led to believe that they had to perform the speech later. Those in the ‘‘no speech’’ condition were simply asked to write an essay for 5 min. Unfortunately, we did not include a manipulation check to test whether this manipulation increased participants’ anxiety levels. All participants were then introduced to the interpretation task. Participants were told that they would be shown pairs of photographs on a computer screen, with one picture being presented at a time. They were asked to press the space bar as soon as they had decided what the facial expression depicted by the picture was. At the start of each trial, participants were instructed to fixate their attention on the ‘‘Ready?’’ message, and 1 The SPS is known as a measure of scrutiny fear and one can argue that decoding facial expressions might be more relevant to interaction anxiety and, thus, the Social Interaction Anxiety Scale (SIAS) should have been used. We used the SPS because it is highly correlated with the SIAS (.66–.72; e.g., Brown et al., 1997; Mattick & Clarke, 1998; .73, Osman, Gutierrez, Barrios, Kopper, & Chiros, 1998; Ries et al., 1998), and Zinbarg and Barlow (1996) found that the SPS and the SIAS loaded on a common factor and the SPS had a higher factor loading than the SIAS.
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press the space bar when they were ready to view the subsequent picture. Then the cue was displayed until participants made a response. The target was then presented immediately after offset of the cue, and it was again displayed until participants pressed the space bar. Then a ‘‘Story’’ or a ‘‘No Story’’ message was displayed after each trial to indicate whether the participant was required to make up a story for the just completed trial before proceeding to the next trial. The ‘‘Story’’ message was displayed on 10 randomly determined trials, and the ‘‘No Story’’ message was displayed on the remaining 50 trials. At the end of a trial designated as a story trial, participants were asked to create a short story that would link both pictures and would also indicate how the people in both pictures were feeling. For the trials when the cue was a string of question marks, participants were asked to include only the target in their story. The experimenter recorded participants’ stories. The critical dependent measure was recorded by the presentation program without the participants’ knowledge and was calculated as the time elapsing between the button press that caused a picture in a picture pair to be displayed on the screen and the subsequent button press that ended the display of that picture. This provided an index of the interpretation latency for each picture in a picture pair. Story coding References to the affect depicted in the pictures in the stories about facial stimuli provided by participants were classified as positive, negative, neutral, bored, or other/unclassifiable by two researchers2 and both pictures on each trial were coded separately. Inter-rater reliability was high, k ¼ .88. References indicating positive emotion experienced by a model (e.g., ‘‘He was happy to get an A.’’) were classified as positive interpretations. The negative category was used for any response mentioning that a person in a picture was experiencing a negative feeling, such as ‘‘He was angry that he got a lower grade than her.’’ Responses such as ‘‘She has a blank facial expression’’ were classified as neutral interpretations. Bored interpretations made an independent category. Finally, the other/missing category was used when there was no way of deciding which category the reference fell into because of insufficient information about the emotion of the person in the picture (e.g., ‘‘She was posing for a picture.’’). Data preparation Individuals’ median RTs were identified and analyzed.3 To maximize power for analyses testing negative interpretive bias in social anxiety, difference scores were calculated by subtracting the RT to the target from the RT to the cue presented on the same trial. The score represents the speeding in RTs when the target is congruent with the cue (e.g., Happy–Happy pair) versus trials when the target is incongruent with the cue (e.g., Happy–Angry pair). By taking into account the individual differences in RTs to the cue, these difference scores provide some control for trial-to-trial fluctuations in attention and also minimize the within-group error term due to individual differences in overall RT. Larger scores indicate more priming as the participants were faster in responding to the target compared to the cue.4 Results Individual differences in the interpretation of faces: self-report data One participant’s data was excluded from the analyses because more than half of this participant’s stories were categorized as ‘other’. Table 1 displays the zero-order Pearson correlation coefficients between the SPS 2 The first author and one undergraduate research assistant trained by the first author served as raters. The raters were blinded to participants’ social anxiety level. The discrepancies between two raters were resolved by a third judge (R.Z.) for the final analysis. 3 Two additional sets of analyses were conducted. In a second set of analyses, RTs more than three standard deviation above the individuals’ mean were discarded as outliers and the analyses were then conducted on trimmed means based on the remaining RT data. In addition, analyses were conducted on all of the data after a log-transformation (cf. Ratcliff, 1993). The three sets of analyses produced the same pattern of results. The results from the trimmed mean and log-transformed analyses are available upon request from the first author. 4 The absolute means for each cue-target condition are available upon request from the first author.
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Table 1 Correlations between the SPS scores and type of interpretation given for each face type and mean proportion of each interpretation in parenthesis Face type
Angry Disgust Happy Neutral
Type of interpretation Negative
Neutral
Positive
Bored
Other
.44/.13 (.64/.69) .35/.45 (.90/.85) .36/.06 (.05/.08) .35/.43 (.25/.32)
.04/.09 (.01/.04) —/— (0/0) .43/.16 (.03/.04) .08/.35 (.41/.31)
—/.05 (0/.02) —/.05 (0/.03) .07/.07 (.88/.81) .09/.07 (.17/.17)
—/— (0/0) —/— (0/0) —/.05 (0/.01) .23/.04 (.04/.05)
.50/.13 (.30/.23) .35/.55 (.10/.12) .34/— (.03/0) .07/.19 (.05/.11)
Note: Some of the correlations could not be computed because certain interpretations were never given by participants (e.g., bored interpretations were never given for an angry face). In each cell the value reported before the slash gives the correlation in the no threat condition and the value reported after the slash gives the correlation in the threat condition. Likewise, the value reported before the slash in the parenthesis gives the mean in the no threat condition and the value reported after the slash gives the mean in the threat condition. The mean proportions do not add up to one across a row within a condition because the numbers have been rounded. SPS ¼ Social Phobia Scale pp.05. pp.01.
scores and the mean number of negative, positive, neutral, bored, and other interpretations given for the neutral faces, as well as those of happy faces, and threatening faces. The majority of responses were consistent with what would be expected of each face type (e.g., negative interpretation was the most frequent interpretation for disgust faces) leading to mostly non-significant correlations between the social anxiety level and type of interpretation. GLMs which allow the continuous nature of the social anxiety measure to be preserved, thereby increasing power, were conducted to test the hypothesis that socially anxious individuals interpret ambiguous facial expressions in a more threatening manner. First, a repeated measures Social Anxiety Speech Face Type Type of Interpretation analysis with participants’ responses5 as the dependent variable was conducted. If social anxiety is related to the tendency to interpret ambiguous stimuli in a negative fashion, there should be a difference in interpretation of neutral facial pictures as a function of social anxiety but not for the other pictures resulting in a three-way interaction between social anxiety, face type, and type of interpretation. In addition, if the speech threat manipulation moderated this three-way interaction, there should be a significant four-way interaction. The four-way interaction between social anxiety, speech, face type, and type of interpretation was significant, F (12, 552) ¼ 2.28, pp.05, Z2 ¼ .05. To investigate the nature of this interaction, the simple three-way interactions between social anxiety, face type, and type of interpretation were examined separately for the two speech conditions. The three-way interaction was significant for the speech condition, F (12, 288) ¼ 3.09, pp.01, Z2 ¼ .13, but not for the no-speech condition, Fo1. The simple two-way interactions between social anxiety and type of interpretation in the speech condition were examined separately for each face type. As predicted, the simple interaction of Social Anxiety Type of Interpretation was significant when the pictures were neutral, F (4, 96) ¼ 2.94, pp.05, Z2 ¼ .12, which resulted from a pattern in which social anxiety was significantly correlated with negative interpretations for neutral faces, r (26) ¼ .43, pp.05. The simple interaction between social anxiety and type of interpretation was not significant when the pictures were either angry or happy (all F’so1). The simple two-way interaction was significant for disgust faces in the speech condition, F (4, 96) ¼ 7.12, pp.01, Z2 ¼ .30, which resulted from a pattern in which social
5
We did not use the total number of each type of interpretation given for each face type as a dependent variable (DV) as some types of faces were presented more than others. Instead, we computed a ratio for each interpretation given for each face type and used the ratio as a DV. For each participant, for example, the number of positive interpretation given for happy faces was divided by the total number of happy faces used for the story trials to get a proportion of positive interpretation for happy faces.
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anxiety was significantly correlated with giving more other/missing interpretations while giving less negative interpretations. Manipulation check for RT data The underlying logic for the RT portion of this study is based on the assumption that a picture of an emotional face will prime the processing of a subsequent target with a congruent facial expression, thus resulting in a faster latency to the target. Thus, we first examined whether there is a priming effect for the congruent facial expressions by investigating the latencies to interpret the target as a function of the preceding cue type. That is, a Cue Type Target Type repeated measures ANOVA was conducted using the RTs to the target as the dependent variable. The RTs are presented in Fig. 1. The basic priming assumption was confirmed by the presence of a significant two-way interaction between cue type and target type, F (4, 200) ¼ 4.89, pp.01, Z2 ¼ .09. The latencies to the targets were faster when the targets were congruent with the cues, and they were slower when the targets were incongruent with the cues in terms of their valence. For example, the latencies to the happy targets were significantly faster when the cues were congruent (i.e., happy) compared to the trials when the cues were incongruent (i.e., threatening, that is angry or disgust), F (1, 50) ¼ 12.75, pp.01, Z2 ¼ .20. Individual differences in the interpretation of faces: RT data6 As the validity of the experimental paradigm was confirmed, we tested our main hypothesis regarding social anxiety and individual differences in the interpretation of neutral faces. Difference scores for each type of pair were calculated as described in section ‘Data preparation’. Table 2 presents the zero-order Pearson correlation coefficients between the SPS scores and these difference scores in the various conditions included in this experiment. To test our main hypothesis, a Social Anxiety Speech Cue Type Target Type mixed GLM was carried out on these difference scores. According to the hypothesis that social anxiety is related to the tendency to interpret ambiguous stimuli in a negative fashion, social anxiety should correlate positively with the difference scores for threatening targets following neutral cues but should not correlate with the difference scores for other targets following neutral cues or with the difference scores for cues other than neutral resulting in a three-way interaction between social anxiety, cue type and target type. In addition, if the effects of social anxiety are most evident when state anxiety is elevated, this three-way interaction should be moderated by the speech manipulation resulting in a four-way interaction. Although the four-way interaction was not significant, F (16, 360) ¼ 1.40, ns, the three-way interaction between social anxiety, cue type and the target type was indeed significant, F (8, 360) ¼ 3.64, pp.01, Z2 ¼ .08. To clarify this significant three-way interaction, five Social Anxiety Target Type repeated measures analyses were conducted—one for each cue type. As expected, the simple two-way interaction of Social Anxiety Target Type was significant when the cues were neutral faces, F (2, 90) ¼ 4.34, pp.05, Z2 ¼ .38. Further analysis revealed that high levels of social anxiety was associated with greater facilitation in the processing of angry targets following neutral cues, r (49) ¼ .34, pp.05, suggesting that social anxiety was associated with the tendency to interpret neutral faces as angry. The association between social anxiety and the tendency to interpret neutral faces as disgust approached conventional levels of statistical significance, r (49) ¼ .23, p ¼ .10. However, social anxiety was not significantly related to tendencies to interpret neutral faces as happy, r (49) ¼ .13, ns. Consistent with our predictions, the simple two-way interactions of Social Anxiety Target Type were not significant when cues were question marks, angry, or happy. However, the simple two-way interaction of Social Anxiety Target Type was significant for disgust cues, F (2, 90) ¼ 5.01, pp.01, Z2 ¼ .45, which was not predicted. Further examination revealed an interesting finding; high levels of social anxiety were significantly associated with faster processing of happy targets following disgust cues, r (49) ¼ .28, pp.05, indicating that 6 The overall pattern of results for the RT data remained largely the same when participants’ depression level (i.e., BDI scores) was entered as a covariate with the one exception that the simple interaction between social anxiety and type of target reported here was no longer significant for happy cues.
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2300 ???
Cue Type Congruent Incongruent
1800
1300 Angry
Disgust
Happy
Target Type Fig. 1. The RT (in ms) to the target depending on the cue type.
Table 2 Correlations between the SPS scores and the difference scores (Cue RT–Target RT) for each cue–target pair Target type
Angry Disgust Happy
Cue type ???
Angry
Disgust
Happy
Neutral
.04 .10 .14
.05 .16 .20
.14 .15 .28
.16 .18 .21
.34 .23y .13
Note: SPS ¼ Social Phobia Scale. pp.05. y pp.10.
disgust cues facilitated the processing of happy targets among highly socially anxious individuals. Social anxiety was not significantly related with facilitated processing of angry, r (49) ¼ .14, ns, or disgust targets, r (49) ¼ .15, ns, when cues were pictures of disgust faces. Post hoc analysis of self-report data As reported above, social anxiety was associated with facilitated processing of happy targets following disgust cues. It might be that happy faces, which are generally perceived as positive, can be interpreted in different ways depending on the context (e.g., ‘‘laughing with’’ versus ‘‘laughing at’’). Thus, viewing a disgust face first might have set up a very different context for highly socially anxious individuals and led them to interpret a happy face as mocking or derision. As a preliminary test of this post hoc explanation, we performed a re-analysis of the results from the coding of the participants’ stories. In this re-analysis, we examined participants’ interpretation for a happy face following a disgust face separately from their interpretation of a happy face following a happy face. All but four participants (their responses were coded as missing) interpreted the happy face following a happy face as happy. In contrast, a sizable minority (26%) interpreted the happy face following a disgust face as mocking or disgusted. A logistic regression was
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conducted with SPS scores as a predictor for making a negative interpretation (i.e., mocking) for a happy face following a disgust face. The results indicated that socially anxious participants were more likely to interpret the happy face as mocking (Wald statistic for the SPS equaled 3.93, pp.05).
Discussion The main finding of this study is that the socially anxious individuals interpreted neutral faces as threatening whereas less socially anxious individuals seemed to interpret neutral faces as neutral. This bias towards interpreting the neutral faces as more threatening was supported by the coding of the self-report stories that participants told about the pictures in the speech threat condition. More importantly, it was confirmed by the finding from our RT analysis that the socially anxious individuals showed a significantly greater tendency for neutral cues to prime angry targets. Less socially anxious individuals, on the other hand, seem to be interpreting the neutral pictures as being neutral in that neutral cues did not seem to prime either threatening or happy targets among these individuals. It might seem that two related alternative explanations could be responsible for these results: (a) attentional bias for threatening cues in socially anxious individuals, and/or (b) the imbalance between the number of positive and negative faces biasing participants toward negative faces resulting in a faster RT to negative faces. If the socially anxious individuals showed a relative speeding of processing threatening targets that followed neutral cues simply because those threatening targets grab socially anxious individuals’ attention, we should have seen similar social anxiety effects regardless of what the cues were. Likewise, if a participant became faster at processing negative faces as they occurred more frequently than positive faces and this imbalance had a greater effect on socially anxious individuals due to their pre-existing attentional biases, socially anxious individuals should have shown faster RT to threat targets regardless of the preceding cue type. This was not the case, however. Therefore, neither attentional biases nor the imbalance between the number of positive and negative faces can fully explain our findings as social anxiety was related to facilitation of processing threatening faces only when the cues were neutral. There might also be a concern whether the design of the present study successfully eliminated a response selection bias explanation. We fully agree that response selection bias is still a viable explanation for the results based on our coding of participants’ stories considered in isolation (especially given the generally positive, albeit mostly non-significant, correlations for negative interpretations of each of the four types of faces with social anxiety in the no-speech condition and the trend, albeit a non-significant one, displayed in Table 1 for negative interpretations to be more frequent for three of the four types of faces in the speech condition compared with the no-speech condition). The results based on the RT data, however, are not vulnerable to response selection bias. Participants were simply asked to press the response key once they figured out the facial expression of the pictures. There were no labels attached to their key-pressing responses so group differences in willingness to use negative labels simply cannot account for our RT results. Our RT results are consistent with Philippot and Douillez’s (2005) speculation that implicit tasks might be more sensitive to interpretive bias than the explicit task that they used. There is some evidence indicating that state anxiety moderates the effect of trait anxiety on selective processing of threatening stimuli (e.g., Calvo & Castillo, 1997; Macleod & Rutherford, 1992). However, we did not find a significant main effect of speech condition or any significant interactions involving speech condition with the RT data. In contrast, a significant interaction involving speech condition was found on the self-report data. At this time, it is unclear why our speech threat had an effect on one domain (i.e., self-report) but not on the other, more implicit domain (i.e., RT). Although the results supported the main hypothesis, we also obtained an unexpected, but interesting result. That is, social anxiety was associated with facilitated processing of happy targets following disgust cues. Our post hoc analysis on self-report data lends some support on the idea that socially anxious individuals might interpret seemingly positive facial expressions in a threatening way depending on the context. That is, socially anxious individuals might be prone to interpret happy faces as mocking if they were already primed by a threatening face. Though this result is consistent with our explanation of the RT result, our explanation is admittedly post hoc and should be considered to be tentative until these results are replicated.
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Overall, the findings reported here indicate that highly socially anxious individuals show an interpretive bias to facial pictures thereby extending the results of earlier studies using verbal stimuli (e.g., Hirsch & Mathews, 2000; MacLeod & Cohen, 1993; Richards & French, 1992). These findings have important implications as they suggest that the highly socially anxious may tend to interpret people’s ambiguous facial expressions as threatening during actual interactions. Acknowledgements Preparation of this article was supported by Grant 1R01 MH65652-01 from the National Institutes of Mental Health and by the Patricia M Nielsen Research Chair Endowment from The Family Institute at Northwestern University of Richard E. Zinbarg. We want to thank undergraduate research assistants who helped with running participants. Portions of this article are based on a thesis submitted by the first author in partial fulfillment of the Master of Science degree at Northwestern University. References American Psychiatric Association. (1994n). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: Author. Amir, N., Foa, E. B., & Coles, M. E. (1998). Negative interpretation bias in social phobia. Behaviour Research and Therapy, 36, 945–957. Brown, E. J., Turovsky, J., Heimberg, R. G., Juster, H. R., Brown, T. A., & Barlow, D. H. (1997). Validation of the Social Interaction Anxiety Scale and the Social Phobia Scale across the anxiety disorders. Psychological Assessment, 9, 21–27. Calvo, M. G., & Castillo, M. D. (1997). Mood-congruent bias in interpretation of ambiguity: Strategic processes and temporary activation. The Quarterly Journal of Experimental Psychology, 50A, 163–182. Clark, D. M., & Wells, A. (1995). A cognitive model of social phobia. In R. G. Heimberg, M. R. Liebowitz, D. A. Hope, & F. R. Schneier (Eds.), Social phobia: Diagnosis, assessment and treatment (pp. 69–93). New York: Guilford Press. Ekman, P., & Friesen, W. V. (1976). Pictures of facial effect [Brochure]. Palo Alto, CA: Consulting Psychologists Press, Inc. Hirsch, C. R., & Mathews, A. (2000). Impaired positive inferential bias in social phobia. Journal of Abnormal Psychology, 109, 705–712. MacLeod, C., & Rutherford, E. (1992). Anxiety and the selective processing of emotional information: Mediating roles of awareness, trait and state variables, and personal relevance of stimulus materials. Behaviour Research and Therapy, 30, 479–491. MacLeod, C., & Cohen, I. L. (1993). Anxiety and the interpretation of ambiguity: A text comprehension study. Journal of Abnormal Psychology, 102, 238–247. Mattick, R. P., & Clarke, J. C. (1998). Development and validation of measures of social phobia scrutiny fear and social interaction anxiety. Behaviour Research and Therapy, 36, 455–470. Osman, A., Gutierrez, P. M., Barrios, F. X., Kopper, B. A., & Chiros, C. E. (1998). The Social Phobia and Social Interaction Anxiety Scales: Evaluation of psychometric properties. Journal of Psychopathology and Behavioral Assessment, 20, 249–264. Philippot, P., & Douilliez, C. (2005). Social phobics do not misinterpret facial expression of emotion. Behaviour Research and Therapy, 43, 639–652. Ratcliff, R. (1993). Methods for dealing with reaction time outliers. Psychological Bulletin, 114, 510–532. Richards, A., & French, C. C. (1992). An anxiety-related bias in semantic activation when processing threat/neutral homographs. Quarterly Journal of Experimental Psychology. A, Human Experimental Psychology, 45A, 503–525. Ries, B. J., McNeil, D. W., Boonew, M. L., Turk, C. L., Carter, L. E., & Heimberg, R. G. (1998). Assessment of contemporary social phobia verbal report instruments. Behaviour Research and Therapy, 36, 983–994. Rozin, P., Lowery, L., & Ebert, R. (1994). Varieties of disgust faces and the structure of disgust. Journal of Personality and Social Psychology, 66, 870–881. Stopa, L., & Clark, D. M. (2000). Social phobia and interpretation of social events. Behaviour Research and Therapy, 38, 273–283. Winton, E. C., Clark, D. M., & Edelmann, R. J. (1995). Social anxiety, fear of negative evaluation and the detection of negative emotion in others. Behaviour Research and Therapy, 33, 193–196. Zinbarg, R. E., & Barlow, D. H. (1996). Structure of anxiety and the anxiety disorders: A hierarchical model. Journal of Abnormal Psychology, 105, 181–193.
Behaviour Research and Therapy 45 (2007) 839–847 www.elsevier.com/locate/brat
Shorter communication
Threat is in the eye of the beholder: Social anxiety and the interpretation of ambiguous facial expressions K. Lira Yoona,, Richard E. Zinbarga,b a
Department of Psychology, Northwestern University, 2029 Sheridan Road, Evanston, IL 60208, USA The Family Institute at Northwestern University, Bette D. Harris Center, 618 Library Pl, Evanston, IL 60201, USA
b
Received 23 September 2005; received in revised form 24 April 2006; accepted 2 May 2006
Abstract The current study investigated the tendency of individuals with high levels of social anxiety to interpret ambiguous facial expressions in a threatening manner. Results obtained from self-report measures were consistent with previous studies in which highly socially anxious individuals endorsed threatening interpretations for ambiguous social information. More importantly, highly socially anxious participants showed relative facilitation of processing of threatening faces following neutral faces when a priming technique was used to eliminate artifact due to response selection bias. These findings support the hypothesized social anxiety-linked interpretive bias. r 2006 Elsevier Ltd. All rights reserved. Keywords: Social anxiety; Interpretive bias; Neutral face
Introduction Researchers have suggested that social anxiety is associated with a tendency to interpret ambiguous social events in a negative manner (e.g., Clark & Wells, 1995). Indeed, studies have shown that social phobics tend to endorse a negative interpretation for ambiguous social scenarios even when a positive interpretation was available (e.g., Amir, Foa, & Coles, 1998; Stopa & Clark, 2000). The basic fear in social phobia is about being negatively evaluated by others (APA, 1994). Since facial expression is an important way of conveying evaluation, pictures of human faces would be somewhat ecologically valid stimuli for research on disambiguation bias related to social anxiety. Of particular note, an image of a face is not the same as a person with whom we are interacting and, thus, it might not be the case that such images are more ecologically valid than linguistic stimuli. An important question, however, is whether the cognitive mechanisms that bias the processing of verbal stimuli among anxious individuals bias the processing of non-verbal stimuli as well. Recent studies have been using emotional facial expressions to test for cognitive biases in socially anxious individuals (e.g., Philippot & Douilliez, 2005), and results are mixed in terms of supporting the hypothesis. Corresponding author. Department of Psychology, University of Miami, P.O. Box 248185, Coral Gables, FL 33124-0751, USA. Tel.: +1 847 877 0501; fax: +1 847 491 7859. E-mail address: [email protected] (K. Lira Yoon).
0005-7967/$ - see front matter r 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.brat.2006.05.004
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For example, socially anxious individuals, when asked to identify the affect (negative vs. neutral) in briefly presented slides of faces, had a significantly lower criterion for identifying negative emotions than the nonanxious group, resulting in a bias towards identifying others’ emotional expressions as negative (Winton, Clark, & Edelmann, 1995). A more recent study, however, did not find any group differences between participants with generalized social phobia, anxiety disorders other than social phobia, and controls with regard to decoding accuracy or attributed emotion intensity to pictures of faces (Philippot & Douilliez, 2005). As MacLeod and Cohen (1993) argued about self-report studies, ‘‘the methodologies used [in the previous studies] have commonly introduced the possibility of experimenter demand effects and have made it impossible to dissociate a genuine interpretative bias from possible response selection bias effects’’ (p. 238). Indeed, because some previous studies (e.g., Amir et al., 1998; Philippot & Douilliez, 2005; Winton et al., 1995) relied solely on self-reports, it is difficult to rule out possible response selection bias. That is, the results from previous studies might reflect a greater tendency among socially anxious individuals to select the negative response option (i.e., response selection bias) rather than genuine on-line interpretive bias. A few studies have been conducted to address response selection bias when studying interpretive bias. For example, MacLeod and Cohen (1993) focused on comprehension latencies for individual sentences to eliminate response selection bias effects and study on-line interpretations. In their study, the first ambiguous sentence of each pair was followed by another sentence that represented a possible continuation of either the threatening or the benign/neutral interpretation of the original sentence. In addition, the first sentence was presented under any one of the three cue conditions designed to impose either a threat or neutral interpretation on this initial sentence or leave it fully ambiguous. The interpretation of the first sentence of each pair was assessed by examining the relative facilitation in reading the threat continuation compared with the neutral continuation. In the fully ambiguous condition, participants high in trait anxiety were indeed faster in reading threat continuations compared with the neutral continuations, whereas participants low in trait anxiety showed the opposite pattern. These results indicate that high trait anxious individuals selectively imposed threatening interpretations on the ambiguous sentences, while low trait anxious individuals selectively imposed non-threatening interpretations on the ambiguous sentences. Whereas there is evidence supporting genuine negative interpretive bias in trait anxiety (MacLeod & Cohen, 1993; Richards & French, 1992) and a lack of positive interpretive bias in social phobia (Hirsch & Mathews, 2000) with linguistic stimuli, as noted above it is still an open question whether the conclusions from these studies generalize to the processing of pictorial stimuli. Therefore, the present study aimed to examine whether socially anxious individuals interpret neutral facial expression in a more threatening manner than do less socially anxious people while eliminating response selection bias as an alternative explanation. We adapted the paradigm developed by MacLeod and Cohen (1993), and used pictures of angry and disgust faces as threatening stimuli. Pictures of disgust faces were included as threatening stimuli, because ‘‘disgust is a rejection-from-self-emotion’’ (Rozin, Lowery, & Ebert, 1994, p. 871). That is, humans reject disgust elicitors from the self (Rozin et al., 1994) and, thus, facial expression of disgust with a straight eye gaze implies aversion to the elicitor (in this case, the participant). Considering that fear of rejection or receiving a ‘‘You are not wanted’’ message is a core concern of social phobics (APA, 1994), we thought it was appropriate to include disgust faces as threatening to examine if socially anxious individuals interpret ambiguous faces not only as expressing anger but also disgust. We used pictures of faces that Ekman and Friesen (1976) classified as neutral to access participants’ interpretations of ambiguous social cues. In particular, we selected those pictures for which sizable minorities of the participants in Ekman and Friesen’s norming study gave alternative labels (such as anger or disgust) besides ‘‘neutral.’’ Because Ekman and Friesen’s neutral faces tend to be interpreted in different ways by different people, these faces serve the purpose of ambiguous stimuli in the current studies. A priming paradigm was used to rule out experimenter demand and response selection bias in explaining the differences between high and low socially anxious individuals’ endorsement of threatening interpretation of pictures of neutral facial expressions. The basic procedure in the current study involved presenting a cue picture of a face followed by a target picture of a face. Participants were instructed to press a response button as soon as they figured out what the facial expression depicted by each picture was. Importantly, the participant’s response did not indicate the content of his or her interpretation but rather just provided an index of his or her latency to reach an interpretation. The reaction times (RT) for the target (i.e., the second
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picture in each pair) should be influenced by the interpretation that a participant originally had imposed on the cue (i.e., the first picture in each pair). In other words, targets consistent with the interpretation imposed on the preceding cue should be primed more and, thus, lead to a faster RT than targets inconsistent with the preceding cue (an assumption that we tested as reported below). Accordingly, if a participant interprets pictures of neutral faces in a threatening way, then his/her RT to a target face representing threat (i.e., angry and disgust) should be speeded up following a neutral cue. Therefore, we predicted that highly socially anxious individuals would show faster latencies than low anxious participants to threatening target faces following neutral faces, indicating the presence of negative interpretive bias for neutral faces. If, however, highly socially anxious individuals do not have a marked negative interpretation style, but rather show a less positive interpretation style than low anxious participants, we expected that low socially anxious individuals would show faster latencies than highly anxious participants to happy target faces following neutral faces. Method Participants The participants were 51 undergraduates randomly selected from the Northwestern University introductory psychology class. Participants’ social anxiety level was assessed based on their scores on the 13-item selfconsciousness subscale of the Social Phobia Scale (SPS; Mattick & Clarke, 1998).1 This subscale has strong internal consistency (a ¼ .92) and construct validity, and is more factorially homogeneous than the full SPS (see Zinbarg & Barlow, 1996 for more information). Materials Stimulus picture sets Sixty picture sets were used in this experiment. Each set included two pictures, one picture serving as a cue and the other as a target. There were five different cues: a string of three question marks, a picture of an angry face, a disgust face, a happy face, and a neutral face. There were three different targets: a picture of an angry face, a disgust face, and a happy face. Thus, there were 15 different types of pairs. All these pictures were obtained from Ekman and Friesen’s (1976) Pictures of Facial Affect; all 14 posers appeared six to nine times throughout. There were no restrictions in terms of pairing cue and target faces except that the same person was never used as a cue and a target in the same trial. There were four blocks of trials, each of which consisted of 15 different types of pairs. The trials were presented in a different block randomized order for each participant. Procedure Participants were tested individually and told that the study was concerned with the effects of self-focused speeches on speech performance and on the processing of facial stimuli. The participant was then given a packet, which contained the 13-item shortened version of the SPS. Then, participants in the ‘‘speech’’ condition were asked to write a speech for 5 min, and they were led to believe that they had to perform the speech later. Those in the ‘‘no speech’’ condition were simply asked to write an essay for 5 min. Unfortunately, we did not include a manipulation check to test whether this manipulation increased participants’ anxiety levels. All participants were then introduced to the interpretation task. Participants were told that they would be shown pairs of photographs on a computer screen, with one picture being presented at a time. They were asked to press the space bar as soon as they had decided what the facial expression depicted by the picture was. At the start of each trial, participants were instructed to fixate their attention on the ‘‘Ready?’’ message, and 1 The SPS is known as a measure of scrutiny fear and one can argue that decoding facial expressions might be more relevant to interaction anxiety and, thus, the Social Interaction Anxiety Scale (SIAS) should have been used. We used the SPS because it is highly correlated with the SIAS (.66–.72; e.g., Brown et al., 1997; Mattick & Clarke, 1998; .73, Osman, Gutierrez, Barrios, Kopper, & Chiros, 1998; Ries et al., 1998), and Zinbarg and Barlow (1996) found that the SPS and the SIAS loaded on a common factor and the SPS had a higher factor loading than the SIAS.
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press the space bar when they were ready to view the subsequent picture. Then the cue was displayed until participants made a response. The target was then presented immediately after offset of the cue, and it was again displayed until participants pressed the space bar. Then a ‘‘Story’’ or a ‘‘No Story’’ message was displayed after each trial to indicate whether the participant was required to make up a story for the just completed trial before proceeding to the next trial. The ‘‘Story’’ message was displayed on 10 randomly determined trials, and the ‘‘No Story’’ message was displayed on the remaining 50 trials. At the end of a trial designated as a story trial, participants were asked to create a short story that would link both pictures and would also indicate how the people in both pictures were feeling. For the trials when the cue was a string of question marks, participants were asked to include only the target in their story. The experimenter recorded participants’ stories. The critical dependent measure was recorded by the presentation program without the participants’ knowledge and was calculated as the time elapsing between the button press that caused a picture in a picture pair to be displayed on the screen and the subsequent button press that ended the display of that picture. This provided an index of the interpretation latency for each picture in a picture pair. Story coding References to the affect depicted in the pictures in the stories about facial stimuli provided by participants were classified as positive, negative, neutral, bored, or other/unclassifiable by two researchers2 and both pictures on each trial were coded separately. Inter-rater reliability was high, k ¼ .88. References indicating positive emotion experienced by a model (e.g., ‘‘He was happy to get an A.’’) were classified as positive interpretations. The negative category was used for any response mentioning that a person in a picture was experiencing a negative feeling, such as ‘‘He was angry that he got a lower grade than her.’’ Responses such as ‘‘She has a blank facial expression’’ were classified as neutral interpretations. Bored interpretations made an independent category. Finally, the other/missing category was used when there was no way of deciding which category the reference fell into because of insufficient information about the emotion of the person in the picture (e.g., ‘‘She was posing for a picture.’’). Data preparation Individuals’ median RTs were identified and analyzed.3 To maximize power for analyses testing negative interpretive bias in social anxiety, difference scores were calculated by subtracting the RT to the target from the RT to the cue presented on the same trial. The score represents the speeding in RTs when the target is congruent with the cue (e.g., Happy–Happy pair) versus trials when the target is incongruent with the cue (e.g., Happy–Angry pair). By taking into account the individual differences in RTs to the cue, these difference scores provide some control for trial-to-trial fluctuations in attention and also minimize the within-group error term due to individual differences in overall RT. Larger scores indicate more priming as the participants were faster in responding to the target compared to the cue.4 Results Individual differences in the interpretation of faces: self-report data One participant’s data was excluded from the analyses because more than half of this participant’s stories were categorized as ‘other’. Table 1 displays the zero-order Pearson correlation coefficients between the SPS 2 The first author and one undergraduate research assistant trained by the first author served as raters. The raters were blinded to participants’ social anxiety level. The discrepancies between two raters were resolved by a third judge (R.Z.) for the final analysis. 3 Two additional sets of analyses were conducted. In a second set of analyses, RTs more than three standard deviation above the individuals’ mean were discarded as outliers and the analyses were then conducted on trimmed means based on the remaining RT data. In addition, analyses were conducted on all of the data after a log-transformation (cf. Ratcliff, 1993). The three sets of analyses produced the same pattern of results. The results from the trimmed mean and log-transformed analyses are available upon request from the first author. 4 The absolute means for each cue-target condition are available upon request from the first author.
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Table 1 Correlations between the SPS scores and type of interpretation given for each face type and mean proportion of each interpretation in parenthesis Face type
Angry Disgust Happy Neutral
Type of interpretation Negative
Neutral
Positive
Bored
Other
.44/.13 (.64/.69) .35/.45 (.90/.85) .36/.06 (.05/.08) .35/.43 (.25/.32)
.04/.09 (.01/.04) —/— (0/0) .43/.16 (.03/.04) .08/.35 (.41/.31)
—/.05 (0/.02) —/.05 (0/.03) .07/.07 (.88/.81) .09/.07 (.17/.17)
—/— (0/0) —/— (0/0) —/.05 (0/.01) .23/.04 (.04/.05)
.50/.13 (.30/.23) .35/.55 (.10/.12) .34/— (.03/0) .07/.19 (.05/.11)
Note: Some of the correlations could not be computed because certain interpretations were never given by participants (e.g., bored interpretations were never given for an angry face). In each cell the value reported before the slash gives the correlation in the no threat condition and the value reported after the slash gives the correlation in the threat condition. Likewise, the value reported before the slash in the parenthesis gives the mean in the no threat condition and the value reported after the slash gives the mean in the threat condition. The mean proportions do not add up to one across a row within a condition because the numbers have been rounded. SPS ¼ Social Phobia Scale pp.05. pp.01.
scores and the mean number of negative, positive, neutral, bored, and other interpretations given for the neutral faces, as well as those of happy faces, and threatening faces. The majority of responses were consistent with what would be expected of each face type (e.g., negative interpretation was the most frequent interpretation for disgust faces) leading to mostly non-significant correlations between the social anxiety level and type of interpretation. GLMs which allow the continuous nature of the social anxiety measure to be preserved, thereby increasing power, were conducted to test the hypothesis that socially anxious individuals interpret ambiguous facial expressions in a more threatening manner. First, a repeated measures Social Anxiety Speech Face Type Type of Interpretation analysis with participants’ responses5 as the dependent variable was conducted. If social anxiety is related to the tendency to interpret ambiguous stimuli in a negative fashion, there should be a difference in interpretation of neutral facial pictures as a function of social anxiety but not for the other pictures resulting in a three-way interaction between social anxiety, face type, and type of interpretation. In addition, if the speech threat manipulation moderated this three-way interaction, there should be a significant four-way interaction. The four-way interaction between social anxiety, speech, face type, and type of interpretation was significant, F (12, 552) ¼ 2.28, pp.05, Z2 ¼ .05. To investigate the nature of this interaction, the simple three-way interactions between social anxiety, face type, and type of interpretation were examined separately for the two speech conditions. The three-way interaction was significant for the speech condition, F (12, 288) ¼ 3.09, pp.01, Z2 ¼ .13, but not for the no-speech condition, Fo1. The simple two-way interactions between social anxiety and type of interpretation in the speech condition were examined separately for each face type. As predicted, the simple interaction of Social Anxiety Type of Interpretation was significant when the pictures were neutral, F (4, 96) ¼ 2.94, pp.05, Z2 ¼ .12, which resulted from a pattern in which social anxiety was significantly correlated with negative interpretations for neutral faces, r (26) ¼ .43, pp.05. The simple interaction between social anxiety and type of interpretation was not significant when the pictures were either angry or happy (all F’so1). The simple two-way interaction was significant for disgust faces in the speech condition, F (4, 96) ¼ 7.12, pp.01, Z2 ¼ .30, which resulted from a pattern in which social
5
We did not use the total number of each type of interpretation given for each face type as a dependent variable (DV) as some types of faces were presented more than others. Instead, we computed a ratio for each interpretation given for each face type and used the ratio as a DV. For each participant, for example, the number of positive interpretation given for happy faces was divided by the total number of happy faces used for the story trials to get a proportion of positive interpretation for happy faces.
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anxiety was significantly correlated with giving more other/missing interpretations while giving less negative interpretations. Manipulation check for RT data The underlying logic for the RT portion of this study is based on the assumption that a picture of an emotional face will prime the processing of a subsequent target with a congruent facial expression, thus resulting in a faster latency to the target. Thus, we first examined whether there is a priming effect for the congruent facial expressions by investigating the latencies to interpret the target as a function of the preceding cue type. That is, a Cue Type Target Type repeated measures ANOVA was conducted using the RTs to the target as the dependent variable. The RTs are presented in Fig. 1. The basic priming assumption was confirmed by the presence of a significant two-way interaction between cue type and target type, F (4, 200) ¼ 4.89, pp.01, Z2 ¼ .09. The latencies to the targets were faster when the targets were congruent with the cues, and they were slower when the targets were incongruent with the cues in terms of their valence. For example, the latencies to the happy targets were significantly faster when the cues were congruent (i.e., happy) compared to the trials when the cues were incongruent (i.e., threatening, that is angry or disgust), F (1, 50) ¼ 12.75, pp.01, Z2 ¼ .20. Individual differences in the interpretation of faces: RT data6 As the validity of the experimental paradigm was confirmed, we tested our main hypothesis regarding social anxiety and individual differences in the interpretation of neutral faces. Difference scores for each type of pair were calculated as described in section ‘Data preparation’. Table 2 presents the zero-order Pearson correlation coefficients between the SPS scores and these difference scores in the various conditions included in this experiment. To test our main hypothesis, a Social Anxiety Speech Cue Type Target Type mixed GLM was carried out on these difference scores. According to the hypothesis that social anxiety is related to the tendency to interpret ambiguous stimuli in a negative fashion, social anxiety should correlate positively with the difference scores for threatening targets following neutral cues but should not correlate with the difference scores for other targets following neutral cues or with the difference scores for cues other than neutral resulting in a three-way interaction between social anxiety, cue type and target type. In addition, if the effects of social anxiety are most evident when state anxiety is elevated, this three-way interaction should be moderated by the speech manipulation resulting in a four-way interaction. Although the four-way interaction was not significant, F (16, 360) ¼ 1.40, ns, the three-way interaction between social anxiety, cue type and the target type was indeed significant, F (8, 360) ¼ 3.64, pp.01, Z2 ¼ .08. To clarify this significant three-way interaction, five Social Anxiety Target Type repeated measures analyses were conducted—one for each cue type. As expected, the simple two-way interaction of Social Anxiety Target Type was significant when the cues were neutral faces, F (2, 90) ¼ 4.34, pp.05, Z2 ¼ .38. Further analysis revealed that high levels of social anxiety was associated with greater facilitation in the processing of angry targets following neutral cues, r (49) ¼ .34, pp.05, suggesting that social anxiety was associated with the tendency to interpret neutral faces as angry. The association between social anxiety and the tendency to interpret neutral faces as disgust approached conventional levels of statistical significance, r (49) ¼ .23, p ¼ .10. However, social anxiety was not significantly related to tendencies to interpret neutral faces as happy, r (49) ¼ .13, ns. Consistent with our predictions, the simple two-way interactions of Social Anxiety Target Type were not significant when cues were question marks, angry, or happy. However, the simple two-way interaction of Social Anxiety Target Type was significant for disgust cues, F (2, 90) ¼ 5.01, pp.01, Z2 ¼ .45, which was not predicted. Further examination revealed an interesting finding; high levels of social anxiety were significantly associated with faster processing of happy targets following disgust cues, r (49) ¼ .28, pp.05, indicating that 6 The overall pattern of results for the RT data remained largely the same when participants’ depression level (i.e., BDI scores) was entered as a covariate with the one exception that the simple interaction between social anxiety and type of target reported here was no longer significant for happy cues.
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2300 ???
Cue Type Congruent Incongruent
1800
1300 Angry
Disgust
Happy
Target Type Fig. 1. The RT (in ms) to the target depending on the cue type.
Table 2 Correlations between the SPS scores and the difference scores (Cue RT–Target RT) for each cue–target pair Target type
Angry Disgust Happy
Cue type ???
Angry
Disgust
Happy
Neutral
.04 .10 .14
.05 .16 .20
.14 .15 .28
.16 .18 .21
.34 .23y .13
Note: SPS ¼ Social Phobia Scale. pp.05. y pp.10.
disgust cues facilitated the processing of happy targets among highly socially anxious individuals. Social anxiety was not significantly related with facilitated processing of angry, r (49) ¼ .14, ns, or disgust targets, r (49) ¼ .15, ns, when cues were pictures of disgust faces. Post hoc analysis of self-report data As reported above, social anxiety was associated with facilitated processing of happy targets following disgust cues. It might be that happy faces, which are generally perceived as positive, can be interpreted in different ways depending on the context (e.g., ‘‘laughing with’’ versus ‘‘laughing at’’). Thus, viewing a disgust face first might have set up a very different context for highly socially anxious individuals and led them to interpret a happy face as mocking or derision. As a preliminary test of this post hoc explanation, we performed a re-analysis of the results from the coding of the participants’ stories. In this re-analysis, we examined participants’ interpretation for a happy face following a disgust face separately from their interpretation of a happy face following a happy face. All but four participants (their responses were coded as missing) interpreted the happy face following a happy face as happy. In contrast, a sizable minority (26%) interpreted the happy face following a disgust face as mocking or disgusted. A logistic regression was
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conducted with SPS scores as a predictor for making a negative interpretation (i.e., mocking) for a happy face following a disgust face. The results indicated that socially anxious participants were more likely to interpret the happy face as mocking (Wald statistic for the SPS equaled 3.93, pp.05).
Discussion The main finding of this study is that the socially anxious individuals interpreted neutral faces as threatening whereas less socially anxious individuals seemed to interpret neutral faces as neutral. This bias towards interpreting the neutral faces as more threatening was supported by the coding of the self-report stories that participants told about the pictures in the speech threat condition. More importantly, it was confirmed by the finding from our RT analysis that the socially anxious individuals showed a significantly greater tendency for neutral cues to prime angry targets. Less socially anxious individuals, on the other hand, seem to be interpreting the neutral pictures as being neutral in that neutral cues did not seem to prime either threatening or happy targets among these individuals. It might seem that two related alternative explanations could be responsible for these results: (a) attentional bias for threatening cues in socially anxious individuals, and/or (b) the imbalance between the number of positive and negative faces biasing participants toward negative faces resulting in a faster RT to negative faces. If the socially anxious individuals showed a relative speeding of processing threatening targets that followed neutral cues simply because those threatening targets grab socially anxious individuals’ attention, we should have seen similar social anxiety effects regardless of what the cues were. Likewise, if a participant became faster at processing negative faces as they occurred more frequently than positive faces and this imbalance had a greater effect on socially anxious individuals due to their pre-existing attentional biases, socially anxious individuals should have shown faster RT to threat targets regardless of the preceding cue type. This was not the case, however. Therefore, neither attentional biases nor the imbalance between the number of positive and negative faces can fully explain our findings as social anxiety was related to facilitation of processing threatening faces only when the cues were neutral. There might also be a concern whether the design of the present study successfully eliminated a response selection bias explanation. We fully agree that response selection bias is still a viable explanation for the results based on our coding of participants’ stories considered in isolation (especially given the generally positive, albeit mostly non-significant, correlations for negative interpretations of each of the four types of faces with social anxiety in the no-speech condition and the trend, albeit a non-significant one, displayed in Table 1 for negative interpretations to be more frequent for three of the four types of faces in the speech condition compared with the no-speech condition). The results based on the RT data, however, are not vulnerable to response selection bias. Participants were simply asked to press the response key once they figured out the facial expression of the pictures. There were no labels attached to their key-pressing responses so group differences in willingness to use negative labels simply cannot account for our RT results. Our RT results are consistent with Philippot and Douillez’s (2005) speculation that implicit tasks might be more sensitive to interpretive bias than the explicit task that they used. There is some evidence indicating that state anxiety moderates the effect of trait anxiety on selective processing of threatening stimuli (e.g., Calvo & Castillo, 1997; Macleod & Rutherford, 1992). However, we did not find a significant main effect of speech condition or any significant interactions involving speech condition with the RT data. In contrast, a significant interaction involving speech condition was found on the self-report data. At this time, it is unclear why our speech threat had an effect on one domain (i.e., self-report) but not on the other, more implicit domain (i.e., RT). Although the results supported the main hypothesis, we also obtained an unexpected, but interesting result. That is, social anxiety was associated with facilitated processing of happy targets following disgust cues. Our post hoc analysis on self-report data lends some support on the idea that socially anxious individuals might interpret seemingly positive facial expressions in a threatening way depending on the context. That is, socially anxious individuals might be prone to interpret happy faces as mocking if they were already primed by a threatening face. Though this result is consistent with our explanation of the RT result, our explanation is admittedly post hoc and should be considered to be tentative until these results are replicated.
ARTICLE IN PRESS K. Lira Yoon, R.E. Zinbarg / Behaviour Research and Therapy 45 (2007) 839–847
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Overall, the findings reported here indicate that highly socially anxious individuals show an interpretive bias to facial pictures thereby extending the results of earlier studies using verbal stimuli (e.g., Hirsch & Mathews, 2000; MacLeod & Cohen, 1993; Richards & French, 1992). These findings have important implications as they suggest that the highly socially anxious may tend to interpret people’s ambiguous facial expressions as threatening during actual interactions. Acknowledgements Preparation of this article was supported by Grant 1R01 MH65652-01 from the National Institutes of Mental Health and by the Patricia M Nielsen Research Chair Endowment from The Family Institute at Northwestern University of Richard E. Zinbarg. We want to thank undergraduate research assistants who helped with running participants. Portions of this article are based on a thesis submitted by the first author in partial fulfillment of the Master of Science degree at Northwestern University. References American Psychiatric Association. (1994n). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: Author. Amir, N., Foa, E. B., & Coles, M. E. (1998). Negative interpretation bias in social phobia. Behaviour Research and Therapy, 36, 945–957. Brown, E. J., Turovsky, J., Heimberg, R. G., Juster, H. R., Brown, T. A., & Barlow, D. H. (1997). Validation of the Social Interaction Anxiety Scale and the Social Phobia Scale across the anxiety disorders. Psychological Assessment, 9, 21–27. Calvo, M. G., & Castillo, M. D. (1997). Mood-congruent bias in interpretation of ambiguity: Strategic processes and temporary activation. The Quarterly Journal of Experimental Psychology, 50A, 163–182. Clark, D. M., & Wells, A. (1995). A cognitive model of social phobia. In R. G. Heimberg, M. R. Liebowitz, D. A. Hope, & F. R. Schneier (Eds.), Social phobia: Diagnosis, assessment and treatment (pp. 69–93). New York: Guilford Press. Ekman, P., & Friesen, W. V. (1976). Pictures of facial effect [Brochure]. Palo Alto, CA: Consulting Psychologists Press, Inc. Hirsch, C. R., & Mathews, A. (2000). Impaired positive inferential bias in social phobia. Journal of Abnormal Psychology, 109, 705–712. MacLeod, C., & Rutherford, E. (1992). Anxiety and the selective processing of emotional information: Mediating roles of awareness, trait and state variables, and personal relevance of stimulus materials. Behaviour Research and Therapy, 30, 479–491. MacLeod, C., & Cohen, I. L. (1993). Anxiety and the interpretation of ambiguity: A text comprehension study. Journal of Abnormal Psychology, 102, 238–247. Mattick, R. P., & Clarke, J. C. (1998). Development and validation of measures of social phobia scrutiny fear and social interaction anxiety. Behaviour Research and Therapy, 36, 455–470. Osman, A., Gutierrez, P. M., Barrios, F. X., Kopper, B. A., & Chiros, C. E. (1998). The Social Phobia and Social Interaction Anxiety Scales: Evaluation of psychometric properties. Journal of Psychopathology and Behavioral Assessment, 20, 249–264. Philippot, P., & Douilliez, C. (2005). Social phobics do not misinterpret facial expression of emotion. Behaviour Research and Therapy, 43, 639–652. Ratcliff, R. (1993). Methods for dealing with reaction time outliers. Psychological Bulletin, 114, 510–532. Richards, A., & French, C. C. (1992). An anxiety-related bias in semantic activation when processing threat/neutral homographs. Quarterly Journal of Experimental Psychology. A, Human Experimental Psychology, 45A, 503–525. Ries, B. J., McNeil, D. W., Boonew, M. L., Turk, C. L., Carter, L. E., & Heimberg, R. G. (1998). Assessment of contemporary social phobia verbal report instruments. Behaviour Research and Therapy, 36, 983–994. Rozin, P., Lowery, L., & Ebert, R. (1994). Varieties of disgust faces and the structure of disgust. Journal of Personality and Social Psychology, 66, 870–881. Stopa, L., & Clark, D. M. (2000). Social phobia and interpretation of social events. Behaviour Research and Therapy, 38, 273–283. Winton, E. C., Clark, D. M., & Edelmann, R. J. (1995). Social anxiety, fear of negative evaluation and the detection of negative emotion in others. Behaviour Research and Therapy, 33, 193–196. Zinbarg, R. E., & Barlow, D. H. (1996). Structure of anxiety and the anxiety disorders: A hierarchical model. Journal of Abnormal Psychology, 105, 181–193.