"TA-DA!": Directional asymmetry in the brain's perception of speech sounds:an MMR study of [t] vs. [d]

TY - CONF

T1 - "TA-DA!"

T2 - Bias in Auditory Perception

AU - Nielsen, Andreas Højlund

AU - Gebauer, Line

AU - Mcgregor, William

AU - Wallentin, Mikkel

PY - 2014/9/18

Y1 - 2014/9/18

N2 - Is the neurally perceived distance from [d] to [t] different from the one from [t] to [d]? To address this question we investigated the mismatch response (MMR) both directional contrasts. The MMR has been shown to be an index of the brain’s auditory change detection. We therefore hypothesized that any potential directional difference in the contrasts would be detectable as a difference in MMRs.The stimuli consisted of the four Danish syllables: [tæ] and [dæ] (meaning ‘take’ and ‘then’, respectively), and [æt] and [æd] (both meaning ‘that’). We used MEG (magnetoencephalography) to measure participants’ (n = 17) mismatch fields (magnetic equivalent of the MMR). We found a main effect of contrast direction (pFWE=0.001 at the cluster-level), peaking around 124 ms after deviance onset. Contrast estimates revealed that this main effect was driven by stronger MMRs to both [tæ] and [æt] than to [dæ] and [æd].Participants’ brains thus seem to experience the perceptual distance from [d] to [t] as larger than that from [t] to [d], despite the acoustic difference being the same for both contrasts. We discuss this finding in relation to previous studies on asymmetries in speech perception, as well as behavioral results on detection of the contrasts.

AB - Is the neurally perceived distance from [d] to [t] different from the one from [t] to [d]? To address this question we investigated the mismatch response (MMR) both directional contrasts. The MMR has been shown to be an index of the brain’s auditory change detection. We therefore hypothesized that any potential directional difference in the contrasts would be detectable as a difference in MMRs.The stimuli consisted of the four Danish syllables: [tæ] and [dæ] (meaning ‘take’ and ‘then’, respectively), and [æt] and [æd] (both meaning ‘that’). We used MEG (magnetoencephalography) to measure participants’ (n = 17) mismatch fields (magnetic equivalent of the MMR). We found a main effect of contrast direction (pFWE=0.001 at the cluster-level), peaking around 124 ms after deviance onset. Contrast estimates revealed that this main effect was driven by stronger MMRs to both [tæ] and [æt] than to [dæ] and [æd].Participants’ brains thus seem to experience the perceptual distance from [d] to [t] as larger than that from [t] to [d], despite the acoustic difference being the same for both contrasts. We discuss this finding in relation to previous studies on asymmetries in speech perception, as well as behavioral results on detection of the contrasts.

M3 - Paper

Y2 - 18 September 2014 through 20 September 2014

ER -