Primacy biases endure the addition of frequency variability.

Publisher: Pergamon Press Country of Publication: England NLM ID: 0020713 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1873-3514 (Electronic) Linking ISSN: 00283932 NLM ISO Abbreviation: Neuropsychologia Subsets: MEDLINE

Publication: Oxford : Pergamon Press
Original Publication: Oxford.

Auditory Perception* ; Evoked Potentials, Auditory*; Acoustic Stimulation/methods ; Bayes Theorem ; Bias ; Electroencephalography ; Humans

The primacy bias (PB) is a phenomenon that indicates the brain does not always process sensory information as an 'ideal Bayesian observer', but rather is disproportionately influenced by first impressions. This study was designed to establish whether a PB observed in auditory event-related potentials (ERPs) to a sequence of sound remained evident in the presence of increased levels of tone frequency variation. Two groups of participants were presented with a novel oddball paradigm, while simultaneously having cortical activity recorded with an EEG. In the control group, participants heard a two-tone sequence where the probability of the two tones of different duration switched after 480 sounds/2.4 min block, so that the tone initially encountered as rare became common and vice versa. The key manipulation introduced in the test group was a change of frequency in each block, removing a key element of regularity. The additional frequency variation resulted in no significant difference in the PB between the groups. The data suggest powerful first learning effects are not disrupted by frequency changes, indicating the robustness of learning heuristics.
(Copyright © 2022 Elsevier Ltd. All rights reserved.)

Keywords: MMN; Precision weighting; Primacy bias; Variability

Date Created: 20220502 Date Completed: 20220517 Latest Revision: 20220623

20240104

10.1016/j.neuropsychologia.2022.108233

35500824