Sound symbolism processing is lateralized to the right temporal region in the prelinguistic infant brain

Jiale Yang,Michiko Asano,So Kanazawa,Mutsumi Imai,Masami K Yamaguchi

doi:10.1038/s41598-019-49917-0

Jiale Yang, Michiko Asano + Show 3 more

Open Access

https://doi.org/10.1038/s41598-019-49917-0

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Abstract

Sound symbolism, which is the systematic and non-arbitrary link between a word and its meaning, has been suggested to bootstrap language acquisition in infants. However, it is unclear how sound symbolism is processed in the infants’ brain. To address this issue, we investigated the cortical response in 11-month-old infants in relation to sound-symbolic correspondences using near-infrared spectroscopy (NIRS). Two types of stimuli were presented: a novel visual stimulus (e.g., a round shape) followed by a novel auditory stimulus that either sound-symbolically matched (moma) or mismatched (kipi) the shape. We found a significant hemodynamic increase in the right temporal area, when the sound and the referent sound were symbolically matched, but this effect was limited to the moma stimulus. The anatomical locus corresponds to the right posterior superior temporal sulcus (rSTS), which is thought to process sound symbolism in adults. These findings suggest that prelinguistic infants have the biological basis to detect cross-modal correspondences between word sounds and visual referents.

Highlights

In traditional linguistics, the arbitrariness of the relationship between sound and meaning is considered a core principle of language[1]
The results of this research revealed that the superior temporal region, which is known to be a cross-modal integration area, plays a key role in sound symbolism processing in 11-month-old infants, as it does in adults
Our findings provide additional support to this hypothesis, the results suggest that not all sound symbolism that adults may sense may be detected by prelinguistic infants[18]

Summary

Introduction

The arbitrariness of the relationship between sound and meaning is considered a core principle of language[1]. Previous behavioral studies have demonstrated that sound symbolism plays a facilitative role in word learning. Research has shown that 14-month-old infants benefit from bouba/kiki type sound-shape correspondence in an associative word learning task[10]. This scaffolding effect continues into toddlerhood, in verb learning[11,12,13]. Some other studies have demonstrated that prelinguistic infants are sensitive to bouba/kiki type sound-shape correspondence[15,16,17]. Www.nature.com/scientificreports infants by examining both published and unpublished work, most of which employed behavioral measures These authors concluded that young infants by and large are sensitive to audition-vision correspondence. Investigations on the neural mechanism underlying sound symbolism processing are not plentiful even in adults, two previous adult functional magnetic resonance imaging (fMRI) studies that used conventional sound symbolic words in Japanese across different semantic domains have produced results broadly consistent with Ramachandran’s hypothesis in that both identified the involvement of the right STS (superior temporal sulcus) area in sound symbolism processing

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