Poster B2, Sunday, March 26, 8:00 – 10:00 am, Pacific Concourse
Attention sharpens prediction error, prediction determines behavior
Alessandro Tavano1, David Poeppel1,2; 1Max Planck Institute for Empirical Aesthetics, Frankfurt am Main, 2New York University
Attention to sensory stimuli is never uniformly distributed. In particular, attention scales up while we anticipate a stimulus that must eventually occur, improving task performance for longer awaited targets (temporal prediction). Within a predictive coding approach to perception, attention also increases the precision (signal-to-noise ratio) with which the mismatch between predicted and actual input is encoded by the brain (sensory prediction error). Here we tested whether prediction and prediction error interact in optimizing behavior or reflect distinct processes. We used the well-established auditory roving standard paradigm (Haenschel et al., 2005), in which the frequency of isochronously delivered, 50-ms pure tones changes unpredictably after a varying number of same tone standard repetitions. Perceived loudness was equalized (Impulse A-weighting). We recorded electroencephalographic data from 26 participants. The analysis focused on evoked brain responses to frequency deviants. Attention to stimuli selectively enhanced the neural encoding of small rather than large frequency differences, as reflected in the deviant N1 response. This supports the precision account and supercedes the traditional attention-capture account based on prediction error magnitude. Participants were faster in responding to longer awaited pitch changes, which also resulted in larger deviant N1 responses, highlighting the effect of temporal prediction. There was no interaction with prediction error magnitude. These results were replicated in a second experiment in which frequency was kept constant and loudness was roved. We conclude that prediction and prediction error partition concurrent but distinct influences of attention on behavior.
Topic Area: ATTENTION: Auditory