The effect of voice-onset-time on dichotic listening with consonant-vowel syllables: a replication study

This is a study designed to investigate the influence of voice-onset-time (VOT) on the results of a dichotic listening (DL) test using consonant-vowel (CV) syllables. A previous investigation of the role played by VOT on dichotic CV performance was performed on native-Norwegian speakers with the Norwegian language version of the DCV test (Rimol, Eichele & Hugdahl, 2006). VOT had a significant effect on ear report with three of the pairings (long-long (LL), short-short (SS) and short-long (SL)) resulting in an average right-ear advantage (REA), while the fourth condition, long-short (LS), resulted in an average left-ear advantage (LEA). These results suggested that voice onset duration influenced ear advantage because the ear to which the syllable with the long VOT performed better than the ear to which the syllable with the short VOT was presented, regardless of which ear it was. It was concluded that VOT influences laterality results of DL tests with CVs more than the classic REA which would have predicted a stable advantage for the right ear across all conditions. The purpose of the current study was to evaluate the effect of VOT on native-English speakers using the English version of the DCV test. If the results observed in the Norwegian study were driven by duration of VOT only, it was hypothesized that the long VOT would also enhance performance in the both ears and produce a LEA during the LS condition among listeners performing the test in another language, as long as the relative durations of VOT remained similar to those in the Norwegian version of the test. It was further hypothesized that if the long VOT does not produce the advantage in left ear performance as seen in the original study, that there may be other factors related to native language that could be influencing laterality during this task. \ud The results of the current study were similar to those of the original study. The SL, SS, and LL conditions produced an average REA, whereas the LS condition produced an average LEA. The SL condition produced the strongest REA and the LS condition produced the strongest LEA across listeners. The results indicate that relative temporal information between presentations to the two ears plays a significant role in laterality results from DL tests. Differences related to native language cannot be ruled out from this study, however, because relative durations of VOT between the Norwegian and English versions were similar. \u