Sound symbolism scaffolds language development in preverbal infants

Abstract

A fundamental question in language development is how infants start to assign meaning to words. Here, using three Electroencephalogram (EEG)-based measures of brain activity, we establish that preverbal 11-month-old infants are sensitive to the non-arbitrary correspondences between language sounds and concepts, that is, to sound symbolism. In each trial, infant participants were presented with a visual stimulus (e.g., a round shape) followed by a novel spoken word that either sound-symbolically matched ("moma") or mismatched ("kipi") the shape. Amplitude increase in the gamma band showed perceptual integration of visual and auditory stimuli in the match condition within 300 msec of word onset. Furthermore, phase synchronization between electrodes at around 400 msec revealed intensified large-scale, left-hemispheric communication between brain regions in the mismatch condition as compared to the match condition, indicating heightened processing effort when integration was more demanding. Finally, event-related brain potentials showed an increased adult-like N400 response - an index of semantic integration difficulty - in the mismatch as compared to the match condition. Together, these findings suggest that 11-month-old infants spontaneously map auditory language onto visual experience by recruiting a cross-modal perceptual processing system and a nascent semantic network within the first year of life.

The sound symbolism bootstrapping hypothesis for language acquisition and language evolution

“…The stronger inter-regional communication in the left hemisphere in Asano et al's infants [68] thus may indicate that the sound-shape pairings were processed in the language-processing network (in the left hemisphere) in 11-month-old infants.…”

“…Previous research has shown that at 11 months, the language-processing network in the infant's brain responded to sound symbolism [68], but it is not clear whether they were able to establish the word -referent associations and retain it in memory. We demonstrated that sound symbolism facilitates word learning in 14-month-old Japanese-speaking infants [69].…”

“…Is infants' ability for cross-modal mapping directly linked to language processing, and if so, how? Asano et al [68] (see also [89]) investigated this question with Japanese-reared 11-month-olds in an EEG study. In each trial, infants were presented with a picture of a shape (spikey or rounded) followed by a novel word ('kipi' or 'moma').…”

The development of spontaneous sound-shape matching in monolingual and bilingual infants during the first year.

“…By the time referential communication fully develops, towards the end of the first year of life, (e.g., Bates, Camaioni, & Volterra, 1975; also see, Marno et al, 2015); infants' neural activity reflects sensitivity to non-arbitrary relationships between linguistic labels and shapes. Asano et al, (2015) recorded neurophysiological responses from eleven-month-old Japanese infants and found evidence for a more effortful integration process when hearing a sound symbolic mismatch ("kipi"), as opposed to a sound symbolic match ("moma"), after the visual presentation of a round shape.…”

Five mechanisms of sound symbolic association

“…An example of this could be when a word denoting something small contains phonemes that are sound symbolically associated with smallness (i.e., an instance of indirect iconicity, discussed later). These congruencies can have effects on language learning (e.g., Asano et al, 2015;Imai, Kita, Nagumo, & Okada, 2008;Perry, Perlman, & Lupyan, 2015; for a review, see Imai & Kita, 2014) and processing (e.g., Kanero, Imai, Okuda, Okada, & Matsuda, 2014;Lockwood & Tuomainen, 2015;Sučević, Savić, Popović, Styles, & Ković, 2015). Moreover, sound symbolic associations have also been shown to impact cognition more broadly, including effects on action (Parise & Pavani, 2011;Rabaglia, Maglio, Krehm, Seok, & Trope, 2016;Vainio, Schulman, Tiippana, & Vainio, 2013;Vainio, Tiainen, Tiippana, Rantala, & Vainio, 2016), memory (Lockwood, Hargoort, & Dingemanse, 2016;Nygaard, Cook, & Namy, 2009;Preziosi & Coane, 2017), and categorization (Ković, Plunkett, & Westermann, 2010;Lupyan & Casasanto, 2015; for a recent review of sound symbolism effects, see Lockwood & Dingemanse, 2015).…”