The ease with which human infants acquire language has long fascinated scientists and parents alike. A recent study published in ‘Science Advances’ takes a significant leap in unravelling this mystery, demonstrating that the neural foundations for language learning are laid before birth. The research by Benedetta Mariani and her team delves into how prenatal exposure to language influences the newborn brain, revealing a remarkable aspect of early human development.
The study was conducted on 49 newborns, just days old, who were prenatally exposed to French. Their brain activity was measured using electroencephalography (EEG) while they listened to speech in French, Spanish, and English. The choice of languages was strategic. Besides French, the language heard in the womb, Spanish and English, were selected as unfamiliar languages, with Spanish being rhythmically similar to French and English rhythmically different.
Crucially, the researchers aimed not just to observe the newborns’ immediate brain responses to these languages. Instead, they sought to understand whether exposure to speech could induce lasting changes in the newborns’ brain dynamics, supporting learning and memory. Another key aspect of the study was determining if these changes were more pronounced for the language heard prenatally.
The approach involved a sophisticated statistical analysis known as detrended fluctuation analysis (DFA), a tool typically used to assess the self-similarity and temporal correlation in time series data. This analysis measures the strength of long-range temporal correlations (LRTCs), revealing how the present state of a process (like brain activity) relates to its past states. In simpler terms, the researchers examined whether previous experiences, like hearing language in the womb, influence how the newborn brain processes information.
The results were illuminating. Following exposure to speech, the newborns’ brain activity exhibited increased LRTCs, particularly in the theta band of brain waves. This finding was most significant when the infants were exposed to French, the language they had experienced prenatally. This suggests that the brain states triggered by previously experienced languages are ‘privileged’ or more readily activated and maintained in the brain.
What does this mean for our understanding of language development? These findings provide compelling evidence that the infant’s brain is already functionally organized by language experiences even before birth. Exposure to speech doesn’t just provoke a fleeting response in the brain; it leads to rapid, lasting changes that enhance the brain’s sensitivity to familiar stimuli, in this case, the native language.
From a broader perspective, this research highlights the remarkable plasticity of the human brain, particularly in its earliest stages. It also underscores the importance of prenatal experiences in shaping future learning and development. While the impact of these early exposures is not absolute—the study acknowledges that children can successfully acquire languages even without prenatal exposure—it sets a foundation that facilitates later language learning.
This study deepens our understanding of the earliest stages of human cognitive development and opens up new avenues for research in neuroscience and language acquisition. It suggests that the prenatal period is not just a passive phase of development but an active time of preparation and priming for the world outside the womb.
Reference: Mariani, B., Nicoletti, G., Barzon, G., et al. (2023). Prenatal experience with language shapes the brain. Science Advances, 9(47), eadj3524. DOI: 10.1126/sciadv.adj3524
