If you suffer from a headache, then you have a brain tumour: Domain-specific reasoning 'bias' and hypochondriasis

We explored whether hypochondriacal patients selectively search for threat-confirming information when asked to judge the validity of conditional rules in the context of general and health threats. We also explored several factors that may underly participants' information selection (e.g., believability of the rule). Hypochondriacal patients (n=20) and healthy controls (n=20) were presented with modified Wason Selection Tasks (WSTs). The WSTs contained safety rules and danger rules. In the context of general threat, both groups of participants adopted a verificationistic strategy in the case of danger rules and a Popperian strategy in the case of safety rules. Importantly, only hypochondriacal persons showed a similar threat-confirming reasoning pattern in the context of health threat. The latter finding contrasts with the earlier study of de Jong et al. (1998) [de Jong, P. J., Haenen, M.-A., Schmidt, A., and Mayer, B. (1998a). Hypochondriasis: the role of fear-confirming reasoning. Behaviour Research and Therapy, 36, 65-74; de Jong, P. J., Mayer, B., van der Hijden, B., Bogels, S., and van den Hout, M. (1998b). Better safe than sorry: reasoning with conditionals in the context of threat. Submitted for publication.] in which both hypochondriacs and healthy controls showed a threat-confirming strategy in the domain of health threat. The WSTs in that study however, contained a (unintended) worry manipulation ('after hearing this, you get worried'), which might have induced a reasoning strategy in controls that is normally restricted to hypochondriacs. Taken together, the present results sustain the idea that the perception of threat activates a better safe than sorry strategy. In the case of phobic threats, such a reasoning strategy immunizes against refutation of phobic convictions.