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In human perception, the presence of exogenous noise has basically two effects: the first, the masking effect, acts in a detrimental way, eventually increasing
the perceptual threshold relative to the stimulus. On the other hand, recent investigations suggest the occurrence, at a certain noise level, of stochastic resonance,
experimentally highlighted by a decrement in the perceptual threshold. Both effects can give important information about the role of exogenous noise in the human brain.
In our research, we investigate the role of exogenous noise in acoustic perception. By performing a "Yes-No" task and adding different amounts of white noise to acoustic stimuli along the whole experiment, we seek to determine the presence of stochastic resonance. The analysis of the behavioural results are performed by fitting to the data a two dimensional surface obtained by assuming a noise-dependence of the psychometric function. In particular we suppose that the mean of the psychometric function, defines the perceptual threshold, varies as a two-parameters hyperbolic function of the noise level; in this way, we account for both masking function (TvC) and, possibly, the occurrence of stochastic resonance. Preliminary data will be presented that show a slight though significant presence of the phenomenon. |
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