Poster E61, Thursday, August 22, 2019, 3:45 – 5:30 pm, Restaurant Hall
Is neural entrainment a basic mechanism for structure building?
Markus Ostarek1, Phillip Alday1, Olivia Gawel1, Johannes Wolfgruber2, Birgit Knudsen1, Francesco Mantegna1,3, Falk Huettig1,4;1Max Planck Institute for Psycholinguistics, 2Graz University of Technology, 3University of Trento, 4Radboud University
Neural entrainment has been proposed as a mechanism for structure building in language and music (Ding et al., 2015; Nozaradan, 2014). In music, this idea is particularly appealing because of the intuitive mapping between perceptual and neural rhythms. The strongest evidence has come from studies in which participants listened to isochronous sequences of identical tones presented at a rate of 2.4 Hz and were asked to imagine hearing the sequence in binary (march) or ternary (waltz) meter (Fujioka et al., 2015; Nozaradan et al., 2011). The critical finding was that in addition to increased signal at the frequency corresponding to the tone rate (2.4 Hz) there was increased signal at the imagined meter frequencies (1.2 Hz for binary and 0.8 Hz for ternary meter). While it is striking that meter tracking was observed without any acoustic cues in the input (and thus had to be endogenous), rhythm perception was confounded with rhythm imagery involving active attention to rhythmic structure. This opens up the possibility that meter-related entrainment reflects conscious attention to rhythmic structure rather than rhythm perception per se. To put this possibility to the test, we conducted two electroencephalography experiments with 19 musicians and 19 non-musicians, focusing on the frequency domain (frequency tagging). In Experiment 1, participants were asked to spot occasional irregularities in otherwise perfectly isochronous sequences (where one of the tones was played 30 ms early). Crucially, participants were cued with count-in beats that induced the perception of metric structure (as indicated by ratings collected after the experiment). Thus participants were perceiving metric structure without consciously focusing their attention on it. In Experiment 2, participants listened to the same tone sequences but were now asked to actively imagine hearing them in particular metric structure (block 1), or tap their finger on the imagined downbeat (block 2). We observed evidence for meter-related neural entrainment only in situations where conscious attention was allocated to rhythmic structure, either implicitly (imagery) or in the form of overt behavior (tapping). Thus, our data suggest that mere rhythm perception is not sufficient for neural entrainment to the meter and that instead entrainment is driven by conscious attention to rhythmic structure. Regarding recent evidence linking neural entrainment to hierarchical structure building in language (Ding et al., 2015), it will be critical to determine whether entrainment has a more fundamental role in language, or whether conscious attention to rhythmically repeating structure can also account for previous results in the language domain.
Themes: Perception: Auditory, Syntax
Method: Electrophysiology (MEG/EEG/ECOG)