Human evolution: fetal language learning (Introduction)

by David Turell , Wednesday, November 29, 2023, 16:19 (150 days ago) @ David Turell
edited by David Turell, Wednesday, November 29, 2023, 16:25

Studies from before birth to after:

https://www.science.org/doi/10.1126/sciadv.adj3524?utm_source=sfmc&utm_medium=email...

"Human infants acquire language with amazing ease. This feat may begin early, possibly even before birth, as hearing is operational by 24 to 28 weeks of gestation. The intrauterine environment acts as a low-pass filter, attenuating frequencies above 600 Hz. As a result, individual speech sounds are suppressed in the low-pass–filtered prenatal speech signal, but prosody, i.e., the melody and rhythm of speech, is preserved. Fetuses already learn from this prenatal experience: Newborns prefer their mother’s voice over other female voices and show a preference for the language their mother spoke during pregnancy over other languages. After birth, as infants get exposed to the full-band speech signal, they become attuned to the fine details of the sound patterns of their native language by the end of the first year of life. What neural mechanisms allow the developing brain to learn from language experience remains, however, poorly understood. Here, we asked whether stimulation with speech may induce dynamical changes able to support learning in newborn infants’ brain activity, and whether this modulation is specific to the language heard prenatally.

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"Together, these results provide the most compelling evidence to date that language experience already shapes the functional organization of the infant brain, even before birth. Exposure to speech leads to rapid but lasting changes in neural dynamics, enhancing LRTCs [long-range temporal correlations] and thereby increasing infants’ sensitivity to previously heard stimuli. This facilitatory effect is specifically present for the language and the frequency band experienced prenatally. These results converge with observations of increased power in the electrophysiological activation of the newborn brain after linguistic stimulation and suggest that the prenatal period lays the foundations for further language development, although it is important to note that its impact is not deterministic, as children, if exposed young, remain capable of acquiring a language even in the absence of prenatal experience with it, e.g., in the case of preterm infants, immigrant or international adoptee children, or after cochlear implantation.

"Whether the facilitatory effect of prenatal experience is specific to the speech domain remains an open question. Behaviorally, it has been shown that newborns recognize music they had been exposed to prenatally, so they show behavioral evidence of learning in auditory domains other than language."

A review of the study:

https://mail.google.com/mail/u/0/#inbox/FMfcgzGwHpbcCjXjcCbgPGvRSnbkKktC

"Fetuses gain the ability to hear sometime between five and seven months gestation. Previous studies had indicated that during this time, they learn to recognize the sounds of music and speaking voices they hear. But whether they really pick up on the language in either has remained unclear. So, researchers fitted one- to five-day-old newborns with electroencephalography (EEG) caps to measure their brain activity. Then they played kids’ stories in English, Spanish, and French—the last of which was their parents’ language. When the French story came at the end, the newborns’ brains reacted differently, exhibiting brain wave patterns that suggested they were already primed to learn their parent’s tongue, according to the authors.

“'These results provide the most compelling evidence to date that language experience already shapes the functional organization of the infant brain, even before birth,” the team writes."

Comment: more discrete evidence the human brain is built to learn language quickly. I believe when sapiens arrived on the scene 315,000 years ago this ability was present by design for future use, considering language is believed to have appeared in fairly full form 50-75,000 years ago. A clear demonstration of design in advance of future use.