Ikeda, A. 1, 2 , Kobayashi, T. 2 & Itakura, S. 1
1 Kyoto University
2 NTT Communication Science Labs
Recent preferential-looking studies have shown that 12-month-old infants can map particular nonsense words (e.g., 'kiki') to particular shapes (e.g., angular shapes) as well as adults, suggesting that infants' sensitivity to non-arbitrary sound-meaning relationships (i.e., sound symbolism) precedes language acquisition (e.g., Starr & Brannon, 2012). Is this sound-meaning correspondence similarly applicable to other properties? This study focused on visual-tactile properties to investigate whether 1-year-old infants can map words to particular visual textures using Japanese onomatopoetic words, which have rich visual-tactile expressions involving sound symbolism. Fifty-five Japanese-learning 16-month-olds (mean=16.0, range=12.1-20.9) were tested using a preferential-looking paradigm conducted in six trials (three pairs: tsuru-tsuru [smooth] vs. toge-toge [spiky], tsubu-tsubu [pebbly] vs. chiku-chiku [pricking], fuwa-fuwa [fluffy] vs. gotsu-gotsu [craggy]) with familiarization and test phases. In the familiarization phase, paired pictures were shown side by side on a black background with audio stimuli ('Look! What is [it] like?'). In the test phase, the same pair was shown with an onomatopoetic word that was congruent with one picture (e.g., 'Which is tsuru-tsuru?'). The test phase was repeated while reversing the left-right arrangement of the pictures. We calculated the proportion of looks to the congruent picture during the test phase. The results show that the infants looked significantly longer than chance at the congruent picture when presented with a pair of tsuru-tsuru and toge-toge (p<.01), but they failed when presented with the other pairs. Furthermore, a frame-by-frame analysis of time-shift looking at the pair of tsuru-tsuru and toge-toge revealed that they spent more time looking at the congruent picture only during the target sentences. That is, they shifted their attention in response to the particular audio stimuli. These results provide evidence for infants' sound-meaning mapping even before learning onomatopoetic words about visual-tactile properties and suggest that their reaction to sound-symbolic words may be instant and momentary.