Emotional modulation of the post-auricular reflex

A large literature now exists on emotional modulation of the startle blink reflex. The current study examined affective modulation of the post-auricular reflex, which can be measured in relation to the same noise probe used to evoke the startle reflex. We recorded the post-auricular reflex during viewing of pictures that varied systematically in emotional valence, content, and intensity. A significant linear valence modulation effect was found, with pleasant pictures potentiating and aversive pictures inhibiting the post-auricular reflex in comparison with neutral pictures. This modulatory effect did not vary as a function of picture content, but it was most robust for highly intense emotional pictures. Implications for the assessment of basic emotional action tendencies are discussed.