Magnitude of the Startle Response and Drive Level

Abstract

The hypothesis that greater drive would be reflected in larger magnitude of startle response to an abrupt auditory stimulus was investigated. The first experiment provided direct support of this hypothesis, demonstrating that rats deprived of water for 48 hr. showed a significantly greater startle response than both 0- ( p < .01) and 24-hour ( p < .025) deprived rats, who did not differ from each other. The second experiment showed an increase in startle in the presence of a former SΔ and a decrease in startle in the presence of a former SD. The results were taken to support the hypothesis of a direct relationship between drive level and startle magnitude, although problems associated with differential postural adjustments affecting the data could not be ruled out.