Gradients of Physiological Arousal in Parachutists as a Function of an Approaching Jump

Continuous recordings of skin conductance, heart rate, and respiration rate were obtained from experienced and novice parachutists during a sequence of events leading up to and following a jump. While novice jumpers showed a sharp rise in physiological activity up to final altitude, experienced jumpers produced an inverted V-shaped curve—i.e., an initial rise was followed by a decline. It was concluded that with repeated exposure to threat, expanding gradients of activa-tion and of inhibition develop, the latter with steeper slope. The early rise in activation provides an automatic signal of danger, while the inhibitory reaction prevents the arousal from becoming excessive, thus providing a highly adaptive mechanism for the mastery of threat. AHE PRESENT REPORT concerns one of a series of studies on the measurement of conflict and stress associated with sport parachuting. By studying parachuting as a source of stress, it is possible to combine an intensely ego-involving real-life situation with a degree of experi-mental control that is normally not pos-sible outside the laboratory. In 1932, Luria made a significant contribution