Institute for Medical Psychology and Behavioral Neurobiology
Dr. Viktor Müller
Perception of visual and acoustic stimuli: New methods of psychophysical scaling
Viktor Müller, University of Tübingen, Institute of Medical Psychology and Behavioral
The present work was a systematic examination of the perception of visual and acoustical stimuli in psychophysical experiment. The purpose was to contrast accounts of the data using Fechner's and Stevens' law, which assume additive and multiplicative mechanisms, respectively. It was revealed that both laws (mechanisms) are present in a common perceptual space (PS); however it was seen here that Fechner's account reflects the sensual component of the PS whereas Stevens', the cognitive. It was found that the involvement of additive and multiplicative mechanisms in perceptual process is different: The additive mechanisms dominated in assessment of stimuli with even marked differences, in assessment of complex auditory stimuli, in motor reaction, and in continuous scaling; the multiplicative mechanisms were dominant in judgment of discrete stimuli as well as in singular reaction components of continuous scaling. The PS is viewed in this work as a dynamic system involving different reaction or assessment components reflecting the conditions of scaling. However, in any act of perception both variance and invariance (i.e. variable and fixed features of PS) can be found. Also studied here were individual differences in the perception of visual and acoustic stimuli. Thus it was confirmed that the concept of Augmenting-Reducing is related to the dynamic nature of the PS. The results showed that differences in intensity of perception between augmenters and reducers were dependent on scaling conditions. The individual scaling strategies were examined and analyzed in terms of personality properties such as Extraversion-Introversion and Neuroticism. The subjective scales were not affected by singular personality features, but by their interaction (Extraversion x Neuroticism). Furthermore, subjects with different relationships between Extraversion and Neuroticism showed differences in intensity of perception as well as in the degree of involvement of additive and multiplicative mechanisms.
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