The absence of right ear advantage for consonants, vowels and tones in white noise

Abstract

The right ear advantage (REA) indichotic listening phenomenon for the perception of consonants has been described since the 1950s. Although REA is readily observed, it has been shown that the presentation of speech stimuli in noise could change the amplitude, or even the direction, of ear advantage (EA). Furthermore, the EA for the perception of vowels and lexical tones were inconclusive to date. The present study therefore explored the effects of white noise, in two signal-to-noise ratios (SNR) (0 dB and -10 dB SNRs), on EA for consonants, vowels and lexical tones. Different syllables were presented to each ear simultaneously, and the participants responded with the syllable they thought was more clearly heard. The response were recorded and scores for each ear was generated. Results revealed an REA in the quiet condition. However, it was diminished in the presence of white noise, and the same trend was found for all three types of linguistic stimuli. The results infer that white noise caused a change in the relative involvement of the two hemispheres in speech processing. The possible alterations of attention by the onset of noise were discussed.