Poster E7, Thursday, August 22, 2019, 3:45 – 5:30 pm, Restaurant Hall
Perceptual anchoring: Infants benefit from auditory predictive coding
Claudia Männel1,2,3, Hellmuth Obrig1,2, Arno Villringer1,2, Merav Ahissar4, Gesa Schaadt1,2,3;1Medical Faculty, University of Leipzig, 2Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, 3Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 4Department of Psychology, The Hebrew University of Jerusalem
Listeners predict upcoming events through experience. The mechanism of predictive coding is functional in infants and adults, as evidenced by prediction errors in the event-related brain potential (ERP). Moreover, adults show behavioral advantages in frequency discrimination in the context of repeated reference tones, which serve as anchors for the processing of subsequent sounds. Despite the evidence of this so-called perceptual anchor effect in adults, the immediate benefit of predictive coding for the processing of new information has not yet been tested in infants. We propose perceptual anchoring to be present in early infancy, potentially serving as a learning mechanism in language acquisition. We therefore presented 2-month-old infants (N = 28) in an ERP study with tone pairs in two anchor blocks and two no-anchor blocks, consisting of 40 tone pairs each. The first tone of the anchor blocks was always constant in frequency (i.e., 279 Hz), while it varied for the no-anchor blocks (i.e., 460 Hz, 358 Hz, 217 Hz, 169 Hz). Crucially, the second tones (i.e., 358 Hz, 316 Hz, 246 Hz, and 217 Hz) had the same frequency across anchor and no-anchor blocks. This experimental design allowed for the evaluation of ERP responses to second tones that were identical across conditions, but either preceded by constant anchor or random (no-anchor) first tones. ERP results for the first tones revealed attenuated obligatory ERP components for the anchor compared to the no-anchor condition, indicating that infants recognized tone repetitions across stimulus pairs. ERP results for the second tones revealed a modulation of infants’ obligatory ERP components, with more positive-going fronto-central responses in the anchor compared to the no-anchor condition. This finding implies that infants processed physically identical stimuli differently depending on the given stimulus environment (i.e., constant vs. variable information). Moreover, the observed ERP effect resembled the adult P2 component that was shown to be modulated by selective attention and training in adults, resulting in faster auditory discrimination. Thus, the constant anchor might have acted as signal in guiding infants’ attention towards the processing of upcoming information. In sum, our study demonstrates for the first time that infants do not only apply predictive coding, but show processing benefits from repeated information in their learning environment, suggesting perceptual anchoring as an essential learning mechanism in language acquisition.
Themes: Development, Speech Perception
Method: Electrophysiology (MEG/EEG/ECOG)