The organization of words and environmental sounds in the second year: Behavioral and electrophysiological evidence

Abstract

The majority of research examining early auditory-semantic processing and organization is based on studies of meaningful relations between words and referents. However, a thorough investigation into the fundamental relation between acoustic signals and meaning requires an understanding of how meaning is associated with both lexical and non-lexical sounds. Indeed, it is unknown how meaningful auditory information that is not lexical (e.g., environmental sounds) is processed and organized in the young brain. To capture the structure of semantic organization for words and environmental sounds, we record event-related potentials as 20-month-olds view images of common nouns (e.g., dog) while hearing words or environmental sounds that match the picture (e.g., "dog" or barking), that are within-category violations (e.g., "cat" or meowing), or that are between-category violations (e.g., "pen" or scribbling). Results show both words and environmental sounds exhibit larger negative amplitudes to between-category violations relative to matches. Unlike words, which show a greater negative response early and consistently to within-category violations, such an effect for environmental sounds occurs late in semantic processing. Thus, as in adults, the young brain represents semantic relations between words and between environmental sounds, though it more readily differentiates semantically similar words compared to environmental sounds.

Infants’ conceptual representations of meaningful verbal and nonverbal sounds

“…This result must be taken with caution and needs to be considered carefully. Though it matches Hendrickson et al [16]suggestion that associated sounds require longer time to process the semantic match between the visual object and the generated sound, it contradicts the results of Cummings and colleagues [15], whereby object recognition was similar in the words and associated sounds condition. Toom and Kukona's [11]VWP study with adults, found greater looking times and semantic activation of the competitors in the associated sounds relative to the words conditions.…”

“…Earlier studies have shown that the second year is marked by an accelerated rate of word learning and understanding, yielding a more efficient recognition [33], and greater sensitivity to the relationships between words than that of associated sounds [16]. Thus, we hypothesized that at 18 months, infants will exhibit greater sensitivity to words, and visual object recognition will be more effective when cued by words than associated sounds.…”

“…dog-"cat") than that of associated sounds (e.g. dog-meowing) [16]. We therefore hypothesized that at 9 months, words will have an advantage over associated sounds in activating conceptual https://doi.org/10.1371/journal.pone.0233968.g004…”

“…To the best of our knowledge, there are only two developmental studies that investigated whether young children process known words and sounds similarly [15,16]. In Cummings et al [15] study, 15-, 20-, and 25-month-old toddlers participated in a looking-while-listening task, during which they viewed pairs of images (e.g.…”

“…Faster object recognition preceded by words was correlated with infants' productive skills. In their recent ERP study, Hendrickson et al [16]investigated the semantic organization of words and associated sounds in the developing brain of 20-month-olds, including three control conditions. Toddlers viewed the target images (e.g.…”