Presentation

Vijayachandra Ramachandra¹, Angela Genter, Kelli Moreno, Kirsten Van Louvender, Sara Moore; ¹Marywood University

A majority of words in a language are generally ‘arbitrary’ (de Saussure, 1916). However, a number of words in languages like Japanese and several words in English such as “meow”, “splash”, “trill”, “moo”, etc. are non-arbitrary (or iconic) (Perniss, Thompson, & Vigliocco, 2010). It is well established that the left hemisphere is dominant for processing words but a recent neuroimaging investigation in Japanese showed that unlike arbitrary words which are processed in the left hemisphere, iconic words show high levels of activation in the right hemisphere, which is generally involved in processing non-verbal sounds (Kanero et al., 2014). In the current study, we carried out two experiments using visual and tactile line bisection tasks in response to arbitrary and iconic auditory stimuli. Line bisection tasks have been used to indirectly measure hemispheric processing of information (see work by Heilman and collaborators). In each of the two experiments of the current study, 20 healthy young right-handed adults (10 men and 10 women) between 18 and 25 years who did not have any sensory or neurological issues participated. In the first experiment, participants (n=20) were asked to bisect 56 horizontal straight lines (21 cm long X 2 mm) at their mid points while listening to different types of auditory stimuli presented randomly – neutral (nasal /m/ consonant), arbitrary words (e.g., air, food, etc.), sensory words (e.g., sniff, mushy, etc.), onomatopoeic words produced without emotions (e.g., oink, moo, etc.), onomatopoeic words with emotions (oink, moo, etc. produced with emotions), and environmental sounds. In the second experiment, different set of participants (n=20), who were blind folded were asked to identify the midpoint of a wooden rod while listening to the same set of stimuli presented in experiment 1. When young typical adults bisect a line, they usually show a more left-side deviation from the midline (pseudoneglect). As expected, we observed the pseudoneglect phenomenon for neutral stimuli in both experiments 1 and 2. The results of the first experiment where we used visual line bisection showed that when compared to the deviations for the neutral stimuli, our participants showed no greater right or left bias for sensory words, arbitrary words and onomatopoeic words indicating that these stimuli had no effect on the spatial allocation of attention as measured by a visual line bisection task. In other words, these stimuli did not lead to a significant hemispheric activation. On the contrary, when compared to the deviations for the neutral stimuli, our participants showed more right bias for onomatopoeic words with emotions and environmental sounds. This indicates a more left hemisphere processing for these stimuli (hemisphere opposite to the side of bias was more activated). The results of the tactile line bisection (experiment 2) were the same as the visual line bisection task (experiment 1) except that in the second experiment there were more significant deviations to the right even for onomatopoeic words without emotions. Comparison of these results with the recent neuroimaging study in Japanese, future directions, and implications for aphasia therapy will also be discussed.

Topic Areas: Meaning: Lexical Semantics, Perception: Auditory