Children learn new words rapidly, even though they may not grasp their full meaning right away. This phenomenon – often called fast mapping - is familiar to every parent, who notice how quickly their children acquire and start using (sometimes to the parent’s embarrassment!) a new word the parent dropped even once accidentally. How exactly this feat is achieved by the young brains remains a mystery.

13.11.2017 | Henriette Blæsild Vuust

Professor yury Shtyrov, CFIN, AU

A new MEG study by NeuroDynamics of Human Communication group (NeDComm Lab) at CFIN investigated activity in children’s brain during rapid acquisition of new words. It showed that neural mechanisms that underlie novel word acquisition in children operate on a much faster scale than known for adults, demonstrating rapid functional changes over just a couple of minutes of listening to them. Moreover, unlike what we know about adults, this rapid and automatic brain plasticity operates for all kinds of new acoustic information that children encouter, be that new words of the native language, foreign speech or even non-speech sounds. The results of the study are published in NeuroImage. 

Neuroimage. 2017 155:450-459. doi: 10.1016/j.neuroimage.2017.03.066. Flexible, rapid and automatic neocortical word form acquisition mechanism in children as revealed by neuromagnetic brain response dynamics. Partanen E, Leminen A, de Paoli S, Bundgaard A, Kingo OS, Krøjgaard P4, Shtyrov Y

Link:
www.ncbi.nlm.nih.gov/pubmed/28389383

Children learn new words and word forms with ease, often acquiring a new word after very few repetitions. Recent neurophysiological research on word form acquisition in adults indicates that novel words can be acquired within minutes of repetitive exposure to them, regardless of the individual's focused attention on the speech input. Although it is well-known that children surpass adults in language acquisition, the developmental aspects of such rapid and automatic neural acquisition mechanisms remain unexplored. To address this open question, we used magnetoencephalography (MEG) to scrutinise brain dynamics elicited by spoken words and word-like sounds in healthy monolingual (Danish) children throughout a 20-min repetitive passive exposure session. We found rapid neural dynamics manifested as an enhancement of early (~100ms) brain activity over the short exposure session, with distinct spatiotemporal patterns for different novel sounds. For novel Danish word forms, signs of such enhancement were seen in the left temporal regions only, suggesting reliance on pre-existing language circuits for acquisition of novel word forms with native phonology. In contrast, exposure both to novel word forms with non-native phonology and to novel non-speech sounds led to activity enhancement in both left and right hemispheres, suggesting that more wide-spread cortical networks contribute to the build-up of memory traces for non-native and non-speech sounds. Similar studies in adults have previously reported more sluggish (~15-25min, as opposed to 4min in the present study) or non-existent neural dynamics for non-native sound acquisition, which might be indicative of a higher degree of plasticity in the children's brain. Overall, the results indicate a rapid and highly plastic mechanism for a dynamic build-up of memory traces for novel acoustic information in the children's brain that operates automatically and recruits bilateral temporal cortical circuits.