Poster E75, Thursday, August 22, 2019, 3:45 – 5:30 pm, Restaurant Hall
Newborns can encode the speech envelope in familiar and unfamiliar languages
Maria Clemencia Ortiz Barajas1,2, Ramón Guevara Erra1,2, Judit Gervain1,2;1Integrative Neuroscience and Cognition Center, Université Paris Descartes, Sorbonne Paris Cité, 2Integrative Neuroscience and Cognition Center, CNRS
When humans listen to speech, their neural activity tracks the slow modulations of speech over time, known as the speech envelope. Studies have shown that a speech stream must contain a well-preserved envelope for humans to understand it, and the quality with which the neural activity tracks this envelope is related to the quality of speech comprehension. However, it has recently been called into question whether this neural mechanism is sufficient for comprehension to take place, as some studies have found envelope-tracking to be present even when speech is unintelligible. To shed new light on this debate we assessed how newborns, who do not yet comprehend language, decode speech. We tested 47 newborns born to French monolingual mothers, within their first 5 days of life. Their experience with speech was, therefore, mostly prenatal. We presented them with naturally spoken sentences in French, Spanish and English, while simultaneously recording their brain activity using electroencephalography (EEG). The use of these 3 languages allowed us to investigate how the newborn brain responds when presented with familiar and unfamiliar languages. To assess speech envelope-tracking we analysed how the neural activity encodes the amplitude and the phase of the speech envelope. Our results show that prenatally French-exposed newborns are able to encode both the amplitude and the phase of the speech envelope in the three languages equally well. Therefore, we have found that the human brain is capable of tracking the speech envelope in familiar and unfamiliar languages already at birth. Our findings reveal that humans’ ability to track the speech envelope does not require experience with language and is, therefore, present in the absence of comprehension. Speech envelope-tracking is thus a basic auditory ability, necessary but not sufficient for language processing.
Themes: Speech Perception, Development
Method: Electrophysiology (MEG/EEG/ECOG)