Bradley, S. D., Angelini, J. R., Lee, S. K., & Lang, A. (2004). Dynamic prepulse: Proximity to scene change alters startle magnitude in emotional TV content [Abstract]. Psychophysiology, 41(Suppl. 1), S62.

Abstract
Previous work has shown that startle reflex magnitude in response to probes less than one second from still picture onset is smaller for both positive and negative affective content compared to neutral content. Beyond one second, however, eyeblink magnitude varies as a function of the emotional content of the slide with negative slides eliciting the largest responses while positive slides elicit the smallest. Research on processing emotional television has shown that scene changes evoke a cardiac orienting response. Hence, scene changes (cuts) should elicit the same prepulse effect as picture onset. To test this, eyeblink magnitude, EKG, and SCR were measured during exposure to affectively normed political advertisements. As predicted, startle magnitudes during negative (compared to positive and neutral) ads were smallest within one second of a cut. Following one second, however, startle magnitudes were larger for both negative and positive ads compared to neutral ads. This largely replicates past findings in a dynamic multi-channel medium where valence builds over time as a result of the audio and visual content of the message. The larger magnitudes for positive compared to neutral ads may be because, overall, political ads are not very arousing, though the negative ads elicited greater self-reported arousal compared to the positive ads. However, there were no differences in SCR. Cardiac deceleration was greater during negative compared to positive and neutral ads, and negative ads resulted in greater recognition sensitivity and a more conservative criterion bias.