Self-generated auditory input is perceived less loudly than the same sounds generated externally. The existence of this phenomenon, called Sensory Attenuation (SA), has been studied for decades and is often explained by motor-based forward models. Recent developments in the research of SA, however, challenge these models. We review the current state of knowledge regarding theoretical implications about the significance of Sensory Attenuation and its role in human behavior and functioning. Focusing on behavioral and electrophysiological results in the auditory domain, we provide an overview of the characteristics and limitations of existing SA paradigms and highlight the problem of isolating SA from other predictive mechanisms. Finally, we explore different hypotheses attempting to explain heterogeneous empirical findings, and the impact of the Predictive Coding Framework in this research area.

Understanding how the brain incorporates sensory and motor information will enable better theory building on human perception and behavior. In this study, we aimed to estimate the influence of predictive mechanisms on the magnitude and variability of sensory attenuation in an online sample. After the presentation of a visual cue stimulus, participants (N = 224) compared the loudness of two consecutive tones in a two-alternative forced choice task. The first tone was either self-initiated or not (active and passive condition, respectively). We further manipulated identity prediction (i.e., the congruence of pre-learned cue-sound combinations; congruent versus incongruent), and the duration of the sound offset (to account for effects of attentional differences between the passive and active condition, 50ms versus 0ms). Contrary to our preregistered hypothesis, we observed enhanced perceptual processing, instead of attenuation, for self-initiated auditory sensory input. Further, our results reveal an effect of fixed sound delays on the processing of motor and non-motor-based predictive information, and may point to according shifts in attention, leading to a perceptual bias. These results challenge previous explanatory models of sensory attenuation and suggest that the role of motor and non-motor-based predictions may need to be reevaluated.

No abstract