Postauricular reflex responses to pictures varying in valence and arousal

Reflexes are modulated by emotions. Much research has revealed that the startle reflexive eyeblink response is modulated by emotion, particularly in response to pictures of emotional scenes. Investigations of other reflexes are limited. Recently, research suggested that the postauricular reflex in response to a startling noise was modulated by emotion. In particular, pleasant stimuli enhanced the postauricular reflex. However, these first investigations were limited: One experiment demonstrated only a marginal difference between the pleasant stimuli and neutral stimuli and the other lacked the typical neutral scene comparison. The present experiment was designed to assess whether significant emotion versus neutral differences would occur. Results demonstrated that pleasant stimuli, regardless of arousal level, evoked larger postauricular reflex activation than neutral and unpleasant emotional stimuli.