The startle probe response: A new measure of emotion?

Twenty undergraduate subjects were presented with unsignaled 50-ms white noise bursts (95 dB) to probe their perceptual processing while viewing 36 colored photographic slides, depicting pleasant/ interesting, neutral/dull, or unpleasant/interesting scenes and objects. Startle magnitudes to the noise bursts as measured by the eyeblink response were largest for unpleasant material and smallest for positive material. This effect was independent of measures of orienting, arousal, and interest in the materials. The results reconcile conflicting animal and human research. Alternative attentional and response matching explanations of these startle probe effects were evaluated. The startle probe is proposed as a broadly useful tool for studying emotion, its development and modification, and for the assessment of pathological anxiety.