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response to high intensity or aversive stimuli and helps the
organism to limit activity with the stimulus. This response
includes increases in sympathetic activity such as cephalic
vasoconstriction and increase in skin conductance.
Lacey and Lacey (1970) extended Sokolov's views of
autonomic responding. They suggested that heart rate
acceleration (tachycardia) during acute affective states is
not a index of arousal per se, but reflects instead the
organism's attempt to limit or terminate bodily turmoil
produced by some stimulus. By contrast, heart rate
deceleration (bradycardia) is induced with intention to
respond to a task, attention to stimuli, and during
vicariously experienced stress. Thus, Lacey and Lacey
argued that the cardiovascular system is not a nonspecific
index of arousal, but a highly specialized response
mechanism which is integrated with affect and cognition and
which also reveals individual differences in the way people
deal with the environment.
Graham and Clifton (1966) pointed out that Sokolov
(1963) and the Laceys (1958) agreed on the existence of an
orienting and defensive response. However, Graham and
Clifton indicated that they did not agree on the
relationship between orienting and defensive responses and
heart rate. Sokolov inferred that heart rate (HR)
acceleration was related to increased sensitivity of
incoming stimuli, whereas HR deceleration was related to