Abstract
Current theoretical models of pain catastrophizing have diverging predictions regarding the role of social context and perceived threat on pain expression. The communal coping model of catastrophizing predicts that high pain catastrophizers display more pain expression in the presence of another, regardless of the threat value of the pain, while a cognitive appraisal model predicts high pain catastrophizers to express more pain when pain has increased threat value, regardless of social context. A 2 × 2 factorial design was used to test the validity of both predictions. Healthy participants with varying levels of pain catastrophizing were exposed to a cold pressor task, consisting of a 60 s immersion and 60 s recovery period. Interestingly, the immersion results revealed that beyond and independent from the effects of pain catastrophizing, the effect of threat on verbal pain report and facial expression was dependent on social context and vice versa. In a threatening context, perceived threat of pain mediated the inhibitory effect of social presence on pain expression, suggesting that the observer acted as a safety signal. In the recovery period, social presence enhanced facial expression, but only when no threat was induced. The results are discussed in terms of the dynamic interaction between social context and threat appraisals.
Introduction
Pain is a universal experience that affects human beings across the life span, and serves an important protective function. Pain urges to interrupt ongoing activity, to escape the source of threat to the body, and to withdraw for healing to take place (Eccleston & Crombez, 1999).
Over the past decade, there has been increasing interest in questions concerning the influence of social context on the experience of pain and associated pain behavior (Keefe and Porter, 2007 and Tait, 2007). Traditionally, the role of social context was framed in social modeling (Craig, 1978) and operant conditioning processes (Fordyce, 1976). Indeed, important others have been shown to influence the experience of pain and how pain is expressed (Craig, 1975, Hadjistavropoulos and Craig, 2002 and Turkat and Guise, 1983). These studies seem to suggest that punishing responses are associated with inhibited expression of verbal and non-verbal pain behavior, while empathic responses are associated with behaviors of greater magnitude (Flor et al., 2002, Jolliffe and Nicholas, 2004 and Lousberg et al., 1992).
More recently, individual differences in the way how pain is catastrophically interpreted have also been examined in a social context of a refined communal coping model (CCM) (Lackner and Gurtman, 2004, Sullivan et al., 2001 and Thorn et al., 2003). Pain catastrophizing has been conceptualized as a way of eliciting empathic responses from others (Sullivan et al., 2004, Sullivan et al., 2001, Thorn et al., 2004 and Thorn et al., 2003). The CCM predicts that high pain catastrophizers will express pain in especially in the presence of others, because they feel vulnerable and feel the need to seek support from others through the expression of pain.
Evidence for the CCM is provided by Sullivan et al. (2004) who showed that during a cold pressor task, healthy subjects scoring high on pain catastrophizing displayed more pain expression in the presence of a neutral observer as compared those who performed the task alone. For the low pain catastrophizers, social context did not affect their pain expression during the pain task. Using a similar experimental pain task, Vervoort and colleagues found children high in pain catastrophizing displayed equal amounts of pain behavior in the presence of both of their parent and a stranger. Their low catastrophizing counterpart, however, were found to express significantly less pain in the presence of a stranger as compared to the presence of own their parent (Vervoort et al., 2008).
Of interest, however, is that studies finding support for CCM have not varied the threat value of the noxious stimulus. Indeed, a number of investigations have shown that threatening information about pain influences pain intensity and pain tolerance (Arntz and Claassens, 2004, Jackson et al., 2005 and Vlaeyen et al., 1995). The central thesis of a cognitive appraisal model (CAM) is that idiosyncratic interpretation of a stimulus determines how strongly it is perceived, and which affect it elicits. The CAM assumes that individuals who catastrophize about pain habitually assign increased threat value to innocuous stimuli, thereby experiencing increased pain-related fear. There is accumulating evidence that catastrophic interpretations of pain produce increased pain-related fear and associated escape, avoidance and safety seeking behaviors, both in experimental and clinical settings (Lethem, Slade, Troup, & Bentley, 1983), for a review, see (Vlaeyen & Linton, 2000).
Although the role of the social context is not specified in the CAM it is arguable that certain social contexts might represent safety cues that signal to the individual that imminent threat will be reduced (e.g. (Lohr et al., 2007 and Tang et al., 2007)). To our knowledge, no studies exist that have manipulated both the threat value of the pain as well as the social presence during a pain task in one single experiment. Manipulations of threat and social presence afford an interesting opportunity to examine competing predictions of CCM and CAM, and to elucidate the relative contribution of the threat value of pain and the presence of a neutral observer in subjects with varying levels of pain catastrophizing. Because both models are not specified in terms of the dependent variable, we decided to include a verbal and non-verbal measure of pain expression in the current study. This is also in line with the recommendation to use both kinds of measures in the assessment of pain because of their unique informational value (Hadjistavropoulos & Craig, 2002). A comparison of CCM and CAM models of pain catastrophizing is not only of theoretical importance, but also has potential clinical implications as tailored and specific treatment of patients who score high on pain catastrophizing are scarce (Thorn et al., 2002 and Thorn et al., 2007). Additionally, current exposure-based treatments for patients with increased pain-related fear have not explicitly addressed the involvement of the social context (Leeuw et al., 2008 and Vlaeyen et al., 2001).
