Bilateral Eye Movements, Attentional Flexibility and Metaphor Comprehension: The Substrate of REM Dreaming?

Explanations for the effects of the rapid eye movements induced during Eye Movement Desensitization Reprocessing (EMDR; Shapiro, 2001 ) have drawn upon an analogy with the eye movements of REM sleep ( Kuiken, Bears, Miall, and Smith, 2002 ). An extension of that analogy posits two orienting systems, one involving threat-fear related mnemonic contextualization and another involving loss-pain related monitoring of conflicting response alternatives. In a study involving individuals who had recently experienced significant loss or trauma, we found that experimentally induced saccadic eye movements decreased reaction times to unexpected stimuli among those reporting traumatic distress (characterized by hyperarousal and intrusive thoughts) and increased reaction times among those reporting separation distress (characterized by vivid reminiscences and the sense of a foreshortened future). Also, we found that saccadic eye movements increased the perceived strikingness of metaphoric sentence endings among those reporting amnesia for events related to either loss or trauma. The eye movements of both EMDR and REM sleep may differently affect the attentional and cognitive reorienting activity of those living with the consequences of loss or trauma. These differences may be evident in their waking reflections and in their dreams.