ABSTRACT

In this chapter we review typical paradigms employed in investigations of startle modification at long lead intervals. We also summarize some of the basic phenomena associated with long lead interval startle modification. Such phenomena include the facilitation or inhibition of startle magnitude as a function of lead stimulus intensity and duration, cardiac deceleration, the modalities of the lead stimulus and the startle probe, whether participants are instructed to attend to or ignore the lead stimulus, and the emotional valence and arousal of the lead stimulus. Both relevant animal and human studies are reviewed, some of which have appeared previously only in doctoral dissertations. In addition, we discuss some of the conceptual issues that have driven much of this research, highlighting particular controversies that have received more attention, such as whether the relationship between lead stimulus intensity and startle amplitude is actually an inverted-U function, and what are the relative contributions of attentional and emotional processes in long lead startle modification.