A tDCS Study of Implicit Learning of Foreign Cognate and Non-Cognate Words Joshua S. Payne*, Paul Mullins & Marie-Josèphe Tainturier Centre for Research on Bilingualism and School of Psychology, Bangor University
Background
Hypotheses
• Left STG/SMG is involved in acquisition and maintenance of form-meaning mappings. • Anodal tDCS over left STG/SMG regions improves vocabulary learning. • First study to explore the effect of tDCS on learning foreign language vocabulary. • Few previous studies manipulate psycholinguistic factors, such as cognate status.
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Cognates should be learned and retained more easily Greater learning gains during active versus sham stimulation Better performance on backward translation post-tDCS, up to a week later> Differential effects of tDCS for cognates and non-cognates
Methods Participants • 32 healthy young adults • Monolingual English speakers • Right-handed • No previous knowledge of Dutch
tDCS Parameters • Single-blind, 1mA tDCS • Active: 20mins (15s ramp on/off) • Sham: 30s (15s ramp on/off) • Anode (35cm2) over CP5 (left STG/SMG) • Cathode (35cm2) over right supraorbital
Stimuli & Materials • Two 30-item Dutch vocabulary lists • 15 Cognates, 15 Non-cognates • Foils: miniature phonological neighbourhoods • Implicit learning task (see Flöel et al., 2008) • Backward translation immediately, 1-day and I-week after learning session
COMETS2 head model and current density simulation.
Results Vocabulary Learning
Backwards Translation
No significant effects of tDCS on backwards translation Although inverse effects of stimulation on cognates as function of phonological memory
• RT analyses ongoing • RT effects in learning may explain translation performance? • Vocabulary implicated in translation performance?
No overall effects of tDCS on FL learning… BUT tDCS facilitates learning non cognates for participants with lower phonological memory Discussion • Cross-language phonological similarity facilitates acquisition of FL vocabulary. • Phonological cognates are retained for a longer period of time following implicit learning. • Overall, active tDCS did not affect performance compared to sham.
Contact: Joshua Payne
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• tDCS may boost acquisition of form-meaning connections of highly dissimilar words, specifically in poorer learners or learners with lower phonological memory. • Future studies should explore phonological processing abilities and other extra-linguistic abilities predict responses to tDCS. • Multi-session studies may results in more robust effects. Acknowledgements: Attendance support by Guarantors of Brain travel grant. Funded by 1 + 3 ESRC DTC Bilingualism Pathway studentship (1367164)
