2021 Fiscal Year Annual Research Report
The role of experience in critical period modulation: From qualitative to quantitative evidence
| Project Area | Inducing lifelong plasticity (iPlasticity) by brain rejuvenation: elucidation and manipulation of critical period mechanisms |
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| Project/Area Number |
20H05919
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| Research Institution | The University of Tokyo |
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Principal Investigator |
辻 晶 東京大学, ニューロインテリジェンス国際研究機構, 講師 (30850490)
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| Project Period (FY) |
2021-04-01 – 2026-03-31
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| Keywords | critical period / language acquisition / speech perception / language input |
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| Outline of Annual Research Achievements |
The present project consists of a longitudinal and cross-sectional dataset. Both were delayed due to the pandemic and were pursued as follows.
As to longitudinal data, we originally planned to include EEG data and start at 1 month of age. We instead focused on behavioral data only (EEG requires close contact) and raised the starting age to 6 months (less vulnerable population). With these changes, we started data collection of 6-18 month-old infants in FY2021, combining at-home audio recordings with in-lab speech perception and word recognition experiments. Throughout FY2022 (carry over from FY2021), we collected a full sample of 30 6-months-old which are progressively followed through. We started developing automatic analyses for the audio recordings (Li et al., 2022).
In FY2021 we bought the EEG machine and started piloting and resolving technical issues with carry-over budget in FY2022. We will not do longitudinal EEG data collection, but will supplement behavioral data with cross-sectional EEG data. As to the planned cross-sectional online dataset, we progressed on technological development to conduct infant speech perception experiments online in FY2021. Online data are still very noisy and lead to imprecise results. We have therefore conducted rigorous tests with adult datasets in order to improve automatic infant gaze direction coding (Hagihara et al., 2022; Tsuji et al., 2022). Finally, while waiting for being able to conduct experiments, we analyzed existing datasets to gain insights on the role of household factors on vocabulary development (Havron et al., 2022).
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Due to the ongoing pandemic, any infant experiments were hard to realize even in FY2021.
At one point we were able to at least resume behavioral experiments. We decided to start the planned longitudinal data collection, which is foreseen to take 2 years in total, with purely behavioral measures, thus decoupling it from EEG which is especially tricky in the pandemic context, since adjustments of the cap required close contact between experimenter and infant. We will therefore supplement the longitudinal behavioral data with cross-sectional EEG data, We bought and installed the EEG machine in FY2021, but delayed the actual start of piloting to FY2022, meaning that we carried over the resources for staff to FY2022. While piloting this new technology for our laboratory, we ran into diverse technical problems with noise. Lacking in-house expertise at IRCN, the postdoc recruited on the project visited experts at Boston Children’s Hospital to investigate the sources of noise encountered and continued piloting.
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| Strategy for Future Research Activity |
We are planning to conclude behavioral longitudinal data collection and in parallel develop methods for automatic analysis of large at-home language input data (no algorithms adapted to Japanese exist). This will allow us to longitudinally link infant language input to their speech perception development and word learning, allowing us to quantify the role of the input during sensitive periods.
We will supplement these data with cross-sectional EEG data, which will allow us more fine-grained insights into speech perception during sensitive periods.
We will also continue improving methods for online data collection towards launching the foreseen cross-sectional data collection of speech perception across contrasts, which will provide us insights into the role of the input on speech perception from a different perspective. While the longitudinal dataset give us the impact of natural variation, this study will complement it by experimentally modifying the saliency and frequency of contrasts infants encounter, providing us with potentially stronger, but less ecologically valid evidence.
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Research Products
(4 results)
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[Journal Article] The effect of older sibling, postnatal maternal stress, and household factors on language development in two- to four-year-old children.2022
Author(s)
Havron, N., Lovcevic, I., Kee, M. Z. L., Chen, H., Chong, Y. S., Daniel, M., Broekman, B. F. P., & Tsuji, S.
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Journal Title
Developmental Psychology.
Volume: 58(11)
Pages: 2096-2113
DOI
Peer Reviewed / Int'l Joint Research
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