Spatial and Temporal Dynamics of Phobics’ Attentional Bias after Subliminal Presentation of Threatening Stimuli

Abstract

Previous studies have confirmed the presence of an attentional bias in phobic subjects’ reaction to threatening stimuli compared to neutral ones (3,11,12). This bias has been demonstrated in most diagnosis belonging to anxiety disorders: social phobia (10), panic disorder (15), generalised anxiety disorder (12), post traumatic stress disorders (6),spider phobia (11). Subliminal exposure of words or pictures perceived as visual flashes can produce interference in the treatment of information revealing activated automatic mechanisms in pre-attentional processes (3,9,16). Recent models have proposed the presence of a route that operates independently of awareness giving an automatic attentional priority to threat. In this context, Mathews and Mackintosh (1998) studied the presence of an active cerebral mechanism «threat evaluation system» that automatically evaluated the threat at «an early, non verbal stage of perception» The model is thus consistent with evidence suggesting anxiety-related interference effects from threatening words or pictures presented out of awareness. These authors assumed that the activation of representations associated with potential danger is increased by input from a threat evaluation system which is similar to ÖHMAN (1994) significance evaluator,for the latter, pictures of feared objects like spiders or snakes, even if they are masked, caused greater skin conductance reponses in phobic than in non phobic subjects (16).