Conscious and Unconscious mechanisms mediating physiological and psychological reactions to noise

摘要

In a classical conditioning paradigm, subjects (Ss) were exposed to short noisy intercom sounds, each followed either by a neutral (control group, CG; N=8) or by a provocating anger inducing instruction (experimental group, EG; N=8). Thereafter, all Ss underwent a mental arithmetic task while again exposed to the intercom sounds, however without any instruction. Regarding the physiological reaction measured by PVA, the EG now exhibited higher arousal and adapted to the sounds slower than the CG, and hence seemed to develop a non-habituating physiological defensive reaction. Regarding the psychological reaction measured by rated annoyance, the EG didn't differ from the CG. Results suggest that reactions to noise are triggered by "warning signals" put out by a PLOF-detector (possible loss of fitness detector), and that this detector is also capable of learning, such that originally neutral sounds, too, can cause reactions. However, even if they induce considerable physiological stress, they neither impair mental performance necessarily, nor are necessarily accompanied by consciously experiencing emotional arousal. We conclude, that the reaction to a noisy event depends, apart from the sound level, also on prior experiences of a person with that sound. However, the first appraisal of such a sound seems to be caused by an unconscious process, which can, but must not, be followed by conscious awareness.