Salience of fear/threat in the affective modulation of the human startle blink.

Affective valence modulates the magnitude of the human startle blink such that blinks are reduced by positive affect and enhanced by negative affect. Do different negative contents similarly potentiate startle? Our first study compared the effects of slides selected to depict positive, neutral, frightening, or disgusting scenes. Blink magnitude was significantly facilitated during frightening pictures and attenuated during positive pictures, but blinks during disgusting pictures did not differ from the neutral condition. Replicating previous work, skin conductance magnitude and baseline EMG activity were greater during affective than neutral scenes. In an additional group of 12 subjects, both reaction times for whether slide content was positive or negative and subsequent picture recall were similar for frightening and disgusting pictures. A follow-up study replicated the blink results for subjects who viewed the same picture set and for subjects who viewed only positive, neutral, and disgusting pictures. These results suggest that scenes depicting fear or threat may be especially salient in the affective augmentation of human startle.