What are some hypothesized mechanisms of action for eye movements in EMDR?
A commonly proposed hypothesis is that dual attention stimulation elicits an orienting response. The orienting response is a natural response of interest and attention that is elicited when attention is drawn to a new stimulus. There are three different models for conceptualizing the role of the orienting response in EMDR: cognitive/information processing (Andrade et al., 1997; Lipke, 1999), neurobiological (Bergmann, 2000; Servan-Schreiber, 2000; Stickgold, 2002) and behavioral (Armstrong & Vaughan, 1996; MacCulloch & Feldman, 1996). These models are not exclusive; to some extent, they view the same phenomenon from different perspectives. Barrowcliff et al. (2001) posit that the orienting in EMDR is actually an investigatory reflex, that results in a basic relaxation response, upon determination that there is no threat; this relaxation contributes to outcome through a process of reciprocal inhibition. Others suggest that the inauguration of an orienting response may disrupt the trauma
