Modulation of the acoustic startle reflex by emotionally-toned film-clips

It has been widely reported that the eyeblink component of the acoustic sta rtle reflex can be modulated by emotionally-toned slide stimuli; pleasant s lides reduce eyeblink amplitudes whereas unpleasant slides enhance them. Th e present study examines the modulation of the acoustic startle reflex by s hort (2-min) film-clips classified as pleasant, unpleasant or neutral, on t he basis of subjective ratings. These film-clips were also evaluated with r espect to their test-retest reliability in producing affective states as we ll as modulating startle reflexes. Overall, results showed significant redu ction of startle during pleasant clips and augmentation during unpleasant c lips. However, on first showing, one of the two unpleasant clips (a medical demonstration film depicting details of toe surgery) actually inhibited th e startle reflex rather than augmented it. This is discussed in terms of th e proposition that only stimuli which arouse fear can be guaranteed to augm ent startle; stimuli that are repulsive may produce perceptual and emotiona l 'blunting' that reduces startle amplitude. (C) 1999 Published by Elsevier Science B.V. All rights reserved.