Disrupting perceptual anchoring to pure-tone sequences in human listeners

Abstract

Perceptual anchoring, a process akin to statistical learning, occurs rapidly and without conscious awareness and is integral to our ability to successfully navigate a noisy world. Here, we investigated anchoring abilities in typical hearing and reading participants by implementing an anchoring paradigm (Agus et al., 2014) using rapid pure-tone sequences (Barascud etal., 2016). We then attempted to disrupt anchoring by applying rapid transcranial magnetic stimulation (rTMS) to frontal cortical regions—areas implicated in the processing of and integration of tone sequences (Abla and Okanoya, 2008). Pure-tone sequences consisted of 50 ms tone-pips that were arranged according to two segments, random (RAND) and regular (REG). RAND segments were generated as tones of random frequencies, and REG segments were generated as in RAND but were iterated to create a repeating pattern. Sequences were presented across three conditions: REPfixed (identical sequences repeated across trials), REPnovel (identical sequences not repeated across trials), and NonREPnovel (nonidentical sequences not repeated across trials). We observed a significantly higher sensitivity to REPfixed relative to REPnovel across all participants (i.e., an anchoring effect). The disruption of frontal regions using rTMS did not significantly impact overall performance but did alter how participants completed the task over time.