As expected, the IMP successfully modified interpretation bias in socially anxious individuals. The IMP group endorsed more benign interpretations and fewer threat interpretations at post-assessment than the ICC group. Thus, both types of interpretation showed the expected change as a result of IMP, and these changes generalized to novel test stimuli. These results converge with Murphy et al. (2007)
, who showed that inducing a benign interpretation bias in socially anxious participants affected ratings of both benign and negative interpretations. This is the first study to show that utilizing corrective feedback can also modify benign and threat interpretations.
Our primary aim was to evaluate the effect of IMP on social anxiety symptoms. Results supported our hypothesis, as participants completing the IMP were less socially anxious compared to the ICC group at post-assessment. Symptom reduction occurred after only eight, 10-min computer sessions with no therapist contact. The between group effect size for the SPAI-SP (d =0.65) is promising. However, these results may not readily translate to patient populations.
The ICC group also showed a significant reduction in threat interpretation endorsement from pre-assessment (65%) to post-assessment (49%). This reduction was likely due to the 50% threat/50% benign feedback contingency received by the ICC. Thus, the ICC could be characterized as a diluted version of the IMP. The ICC group also showed a 15% reduction in social anxiety symptoms compared to a 30% reduction in the IMP group. Since none of the ICC participants believed they received the active condition, changes in this group were not likely due to demand effects. The reduction in the ICC could have been due to the reduction in threat interpretation endorsement. It may also reflect a non-specific response to receiving attention from an experimenter on eight occasions. Finally, the reduction may also reflect regression to the mean, as participants were selected for having high scores on the SPAI-SP.
Our final hypothesis examined mediators of change in the current study. Changes in benign interpretation endorsement, as well as benign and threat endorsement levels at the 5th session (approximately mid-procedure), mediated the effect of group on social anxiety symptoms. These results are consistent with our hypothesis that changing interpretation biases would lead to a reduction in social anxiety symptoms. Change in threat interpretation was not a significant mediator. However, regression analyses revealed that change in threat was a marginal predictor (p= .075) of change in social anxiety, when change in benign interpretation and group were included in the model. Thus, the current study may be underpowered to detect the relationship between change in threat interpretation and change in social anxiety.
These findings suggest that inducing a benign bias and reducing a threat bias may lead to reductions in social anxiety. However, the current study cannot determine whether both types of bias require modification in order to affect social anxiety. Previous CBM studies that only induced a benign bias showed that targeting benign interpretations was sufficient to affect general anxiety symptoms (e.g., Mathews, Ridgeway, Cook, & Yiend, 2007
). However, future research should compare the effects of paradigms that induce a benign bias, reduce threat bias, or both to determine which mechanisms are important for affecting social anxiety.
There are several potential mechanisms of change in the current study. If IMP successfully changed interpretation bias, participants may have started interpreting ambiguous cues in their daily life differently, leading to less anxiety and decreased avoidance. However, alternative explanations should also be considered. For example, IMP may have caused participants to generate more positive images of themselves in social situations while completing the task. Alternatively, IMP may have illuminated participants’ negative interpretive style and encouraged them to challenge their thinking patterns, similar to cognitive restructuring. Identifying the mechanisms of change will be important for future research aiming to enhance the effects on social anxiety.
Durability of induced interpretation bias has received little attention. To date, examination of the durability of interpretation bias change has been limited to 24 hours for single-session CBM (Yiend, Mackintosh, & Mathews, 2005
) and one week for four session CBM (Mathews, Ridgeway, Cook, & Yiend, 2007
). One would expect that eight sessions of interpretation modification would induce longer lasting changes in interpretation bias. In the current study, effects on interpretation bias and social anxiety symptoms lasted a minimum of two days and up to one week. However, we did not examine long-term durability. Future research examining the maintenance of induced interpretation biases is needed for theoretical and clinical reasons. It will be important theoretically to determine whether CBM procedures induce changes that fundamentally alter the cognitive processes that maintain social anxiety or if they simply prime transient response patterns. Should IMP be used clinically, it will be important to determine whether short-term CBM induces long-term interpretation change or if long-term change requires the repeated administration of CBM.
The current study demonstrates that it is feasible to translate CBM procedures to a multi-session, intervention format. Future research should examine methods of enhancing the effects of IMP on anxiety. Larger effects may be necessary for clinical samples and might be obtained by increasing the number of sessions or adding psychoeducation. Adding self-imagery instructions to the IMP might enhance effects on mood (e.g., Holmes, Mathews, Dalgleish, & Mackintosh, 2006
). Finally, using different materials during each session could strengthen the IMP’s effects. In the current study, each session presented the same stimuli. We might expect that introducing new stimuli would help generalize changes in interpretation to real life situations or keep participants better engaged in the task. However, it is also possible that the repetition of the same stimuli in each session caused the process of accepting benign interpretations and rejecting negative interpretations to become less effortful.
The influence of awareness of training contingencies has received little attention in CBM research. To our knowledge, only one study has examined this issue. Salemink, van den Hout, and Kindt (2007a)
compared positive interpretation training and negative interpretation training in a non-anxious sample. Participants read ambiguous stories that ended positively or negatively, depending on their assigned condition. At the end of the experiment, the authors assessed whether participants had explicitly learned a rule about the emotional valence of the training stimuli by asking participants to rate how negatively or positively the stories ended. In the positive training condition, 93% of the participants indicated that the stories ended positively, and 88% of the negatively trained participants indicated that the stories ended negatively.
We did not comprehensively assess participants’ explicit awareness of the training contingencies in the current study. However, the IMP group’s changes in endorsement levels suggest that participants became aware of the “rules.” Moreover, IMP participants who were aware that they received an active condition showed greater changes in interpretation bias. Awareness of training contingencies may affect results differently, depending on the paradigm used. Thus, future research should assess awareness levels, as well as manipulate awareness to explore whether awareness affects anxiety response. For example, awareness manipulations could inform researchers about the utility of providing a rationale to participants prior to completing CBM. It is possible that providing a rationale would enhance effects of the IMP because it could decrease participants’ negative reaction to receiving negative feedback. Alternatively, if CBM effects are superior when achieved outside participants’ awareness, a rationale might interfere.
Finally, future research is needed to compare the existing methods of modifying interpretation bias. The current paradigm differed from previous studies because it used feedback to manipulate interpretation, rather than limiting participants’ exposure to a particular type of interpretation. Thus, future studies are needed to determine which CBM procedure, or combination of procedures, is most efficacious in changing interpretation and anxiety symptoms.
Although our findings are promising, there are several limitations of the current study. First, this initial trial of IMP comprised a small, analogue sample. Replication in a larger and more diverse clinical sample is necessary before any conclusions can be made about the clinical utility of IMP for Social Phobia. However, our participants’ baseline SPAI-SP scores were comparable to those reported in treatment outcome studies (e.g., Cox et al., 1998
; Hofmann, Moscovitch, Kim, & Taylor, 2004
), and thus it is possible that our results would generalize to clinical samples.
Second, we did not include all possible control groups. The current control group was identical to the IMP in all aspects, except for the feedback contingency. We chose this type of control condition in an attempt to isolate a specific mechanism (i.e., feedback contingency). However, future studies might include different control conditions, such as a no feedback condition, wait-list, or relaxation condition, to ensure that group differences are not influenced by the type of control condition. Third, we relied exclusively on self-report measures in this initial trial and did not include a behavioral assessment (e.g., speech challenge). Including additional types of assessments would provide more information about clinically meaningful change.
The possibility of demand effects must be considered. Participants were aware that they could have been assigned to an active condition designed to reduce social anxiety, and they received research credit and/or monetary compensation. However, less than half of IMP participants believed they received the active condition. Additionally, studies that have manipulated interpretation and not informed participants of the purpose of the task have also found effects on anxiety (e.g., Wilson et al., 2006
). Thus, experimental demand is not likely the only explanation for the current results. However, future research should include behavioral assessments that are less susceptible to demand effects than self-report measures.
Finally, we did not include an independent measure of interpretation bias. Thus, it is not clear whether the IMP actually changed interpretation processes or if participants simply learned a rule that they applied to a specific task. This is an important distinction, as previous studies that have included independent measures of interpretation have not found that changes in interpretation on a training task generalized to a different task (e.g., Salemink, van den Hout, & Kindt, 2007b
These limitations notwithstanding, the current results have potential clinical applications. Changes in interpretation bias are often observed after cognitive-behavioral treatment for Social Phobia (e.g., Franklin, Huppert, Langer, Leiberg, & Foa, 2005
). One application of IMP may be to enhance or accelerate changes in interpretation bias during CBT (e.g., IMP disseminated as homework assignment). Similar to all computerized interventions, IMP may reduce clinician time and could be disseminated in various settings (e.g., primary care clinic via computers in waiting or exam rooms, self-help via the Internet). Because cognitive biases are implicated in many domains of psychopathology, the translation of CBM methodology into interventions may prove useful for numerous disorders.