The relationship between refractory phase and negative adaptation in reflex response. I.

Abstract

Two successive noise stimuli were presented to guinea pigs in such a way that the 2nd stimulus fell in the relative refractory phase or in the supernormal phase of the body (start) reflex caused by the 1st stimulus. The effect of the interrelations of the stimuli on the rates of adaptation of the resulting body (start) reflexes was studied. Large individual differences were found. Adaptation was most rapid at 1st and became complete after a sufficient number of stimulations. The earlier the 2nd stimulus occurs in the relative refractory phase of the 1st reflex the less effective were both the 1st and 2nd stimuli in producing negative adaptation. Conversely, the later the 2nd stimulus occurs in the relatiye refractory phase the more effective were both stimuli in producing negative adaptation. Stimuli falling in the supernormal phase (one case) were less effective in producing negative adaptation.