Across Hemispheres: Comparing Interhemispheric Transfer Times of Japanese and Americans

Andrew J. Dimond and Aaron Tiesling-Rusch, Beloit College

Full manuscript: www.kon.org/urc/v12/dimond.html

Abstract:This study sought to determine whether hemispheric differences in language processing would lead to differences in interhemispheric transfer time (IHTT), the time it takes for information to be transmitted from one hemisphere of the brain to the other, between English speaking Americans and Japanese speakers in Japan. Compared to English, reading and writing Japanese requires more bilateral brain activity, and as a result may impact IHTT in a manner similar to previous findings regarding people that frequently play an instrument. We recruited participants from both the United States and Japan and used a manual response reaction time task to estimate the participants’ IHTT. We found that there was no cross-cultural difference in the IHTT of American and Japanese participants, which indicates the possibility that the results from other IHTT studies, which only used Americans, may be generalizable to other national groups.

Introduction Interhemispheric transfer time (IHTT) is a measure of how long it takes for information to be sent from one hemisphere of the brain to the other across the corpus callosum (Marzi, Bisiacchi, & Nicoletti, 1991). Studies frequently use a technique known as the Poffenberger Paradigm to estimate IHTT (Bayer, Kessler, Güntürkün, & Hausmann, 2008; Bernard, 2011; Buse et al., 2012). The Poffenberger Paradigm involves a simple reaction time task in which participants give unimanual responses to stimuli that are presented separately to the participants’ left- and right-visual fields (Poffenberger, 1912). The participants go through the task twice, once responding with their right-hands and a second time responding with their left-hands. The reaction times from the ipsilateral hand and visual field conditions are taken and subtracted from the contralateral conditions and the result is considered an estimate of the participants’ IHTT. On average, previous studies have reported an IHTT estimate of 4-12ms and right-hemisphere to left-hemisphere transfer is usually faster than left-hemisphere to right-hemisphere transfer by approximately 2-3ms (Marzi, Bisiacchi, & Nicoletti, 1991).

Read t full manuscript: www.kon.org/urc/v12/dimond.html