Language experience shapes predictive coding of rhythmic sound sequences
Ikusi/ Ireki
Data
2024Egilea
Morucci, Piermatteo
Nara, Sanjeev
Lizarazu, Mikel
Martin, Clara
Molinaro, Nicola
Piermatteo MorucciSanjeev NaraMikel LizarazuClara MartinNicola Molinaro (2024) Language experience shapes predictive coding of rhythmic sound sequences eLife 12:RP91636.
eLife
eLife
Laburpena
Perceptual systems heavily rely on prior knowledge and predictions to make sense of
the environment. Predictions can originate from multiple sources of information, including contextual
short-term
priors, based on isolated temporal situations, and context-independent
long-term
priors, arising from extended exposure to statistical regularities. While the effects of short-term
predictions on auditory perception have been well-documented,
how long-term
predictions shape
early auditory processing is poorly understood. To address this, we recorded magnetoencephalography
data from native speakers of two languages with different word orders (Spanish: functor-initial
vs Basque: functor-final)
listening to simple sequences of binary sounds alternating in duration
with occasional omissions. We hypothesized that, together with contextual transition probabilities,
the auditory system uses the characteristic prosodic cues (duration) associated with the native
language’s word order as an internal model to generate long-term
predictions about incoming
non-linguistic
sounds. Consistent with our hypothesis, we found that the amplitude of the mismatch
negativity elicited by sound omissions varied orthogonally depending on the speaker’s linguistic
background and was most pronounced in the left auditory cortex. Importantly, listening to binary
sounds alternating in pitch instead of duration did not yield group differences, confirming that the
above results were driven by the hypothesized long-term
‘duration’ prior. These findings show that
experience with a given language can shape a fundamental aspect of human perception – the neural
processing of rhythmic sounds – and provides direct evidence for a long-term
predictive coding
system in the auditory cortex that uses auditory schemes learned over a lifetime to process incoming
sound sequences.