ABSTRACT

Brief startle probes presented while people perceive emotionally evocative events are systematically and differentially modulated according to the affective valence of the foreground stimulus content: Unpleasant stimuli evoke a potentiated reflex to the startle probe that exceeds the normal reaction; pleasant stimuli occasion a relative inhibition of reflex magnitude. This chapter reviews theory and data relevant to affective modulation of the startle reflex. Properties of the startle probe (including sensory modality, intensity, aversiveness, task, timing, laterality, and response) and of the perceptual stimulus (including duration, repetition, blocking, intensity, and semantic or emotional category) are discussed as they impact on the pattern of affective startle modulation. Taken together, these studies elucidate further the nature of affective startle modulation, and provide support for the idea that the startle reflex is a useful measure of motivation and emotion.