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A speaking tutor in instructional videos enhances foreign language word acquisition: N400 and behavioral evidence
Poster Session D, Thursday, October 1, 4:30 - 6:30 pm, Wangari Maathai
Xueqiao Li1, Lili Tian2, Hyeonjeong Jeong3, Piia Astikainen1; 1University of Jyväskylä, 2Aalto University, 3Tohoku University
Learning the meanings of words is a fundamental component of second-language acquisition. However, it remains unclear whether the social context of learning—such as the presence of a tutor articulating the words—facilitates vocabulary acquisition. Here, we combined behavioral and neurophysiological measures to investigate the role of a tutor in video-mediated language learning, and aimed to clarify how social presence and visual cues of speaking influence the learning of novel word meanings. Twenty-nine native Finnish-speaking adults learned 114 Mandarin Chinese words from prerecorded videos in three within-subject learning conditions: a speaking tutor (with visible articulatory lip movements), a silent tutor (visible but without speech-related lip movements), and no tutor (auditory input only). Learning was followed by a word–picture identification test: on each trial, participants first heard a learned word, then saw a picture, and then judged whether the pair matched what they had learned (congruent vs. incongruent). This learning–testing sequence was repeated twice to examine learning dynamics. ERPs recorded during the test were time-locked to the auditory word onset and subsequent picture onset. Single-trial mean amplitudes were extracted for the word-locked auditory N400 (400–600 ms, fronto-central; at least 40 trials per learning condition and testing block) as an index of semantic activation, and for the picture-locked N400 (300–450 ms, centro-parietal; at least 40 trials per learning condition and congruency) as an index of word–picture semantic congruency processing. Both components were analyzed using linear mixed-effects models with trial-level accuracy as a covariate to examine the link between N400 amplitude and behavioral performance. All three conditions showed successful learning: identification accuracy and response times improved from the first to the second testing block. The picture-locked N400 showed a robust congruency effect, suggesting that word–picture associations were established. This congruency effect was present only on correct trials, further linking the neural response to successful word–picture mapping. Importantly, learning conditions differed in response times and the word-locked N400. Participants responded faster after learning with the speaking tutor than in the silent-tutor and no-tutor conditions. For the word-locked N400, the three conditions did not differ in the first testing block. By the second testing block, however, words learned with the speaking tutor elicited a more negative N400 response than words learned in the silent-tutor and no-tutor conditions. Only the speaking tutor condition showed an increase in N400 negativity across testing blocks. Correct trials showed more negative word-locked N400 amplitudes, linking greater N400 negativity to successful word retrieval. The enhanced negativity in the speaking-tutor condition may therefore reflect stronger lexical–semantic activation during retrieval. These findings suggest that a speaking tutor in instructional videos enhances foreign language word learning by promoting stronger semantic activation. The silent-tutor condition, which provided visual social presence without visible speech articulation, did not differ from the no-tutor condition, suggesting that visible articulatory cues, rather than social presence alone, supported word learning. These findings highlight the potential value of explicit audiovisual speech cues for strengthening word acquisition.
Topic Areas: Language Development/Acquisition, Meaning: Lexical Semantics