Eur. Phys. J. B 69, 155-159 (2009)
https://doi.org/10.1140/epjb/e2009-00107-6

Statistically robust evidence of stochastic resonance in human auditory perceptual system

¹ Department of Physics, University of Trento, 38100 Trento-Povo, Italy
² CIMeC, Center for Mind/Brain Sciences, University of Trento, 38068 Rovereto, Italy
³ DSBTA, Section of Human Physiology, University of Ferrara, 44100 Ferrara, Italy
⁴ Department of Cognitive Sciences and Education, University of Trento, 38068 Rovereto, Italy
⁵ Department of Physics and CNISM – Unità di Trento, University of Trento, 38100 Trento-Povo, Italy

Corresponding author: ^a ricci@science.unitn.it

Received: 28 November 2008
Revised: 20 February 2009
Published online: 21 March 2009

Abstract

In human perception, exogenous noise is known to yield a masking effect, i.e. an increase of the perceptual threshold relative to a stimulus acting on the same modality. However, somehow counter-intuitively, the opposite mechanism can occasionally occur: a decrease of the perceptual threshold for a non-vanishing, virtuous amount of noise. This mechanism, called stochastic resonance, is deemed to provide important information about the role of noise in the human brain. In this paper, we investigate stochastic resonance in a detection task in the auditory modality. Normal-hearing participants were asked to judge the presence of acoustic stimuli of different intensity and superimposed to different levels of white noise. The matrix-like outcomes of a behavioural experiment were fitted by a two-dimensional, noise-dependent psychometric function. The fit revealed a statistically significant stochastic resonance in 43% of the experimental runs. We conclude that, in the auditory modality, stochastic resonance is a tiny effect that, under conventional circumstances, is largely overrun by standard masking.