Selective Influences of Precision and Power Grips on Speech Categorization

Abstract

Recent studies have shown that articulatory gestures are systematically associated with specific manual grip actions. Here we show that executing such actions can influence performance on a speech-categorization task. Participants watched and/or listened to speech stimuli while executing either a power or a precision grip. Grip performance influenced the syllable categorization by increasing the proportion of responses of the syllable congruent with the executed grip (power grip—[ke] and precision grip—[te]). Two follow-up experiments indicated that the effect was based on action-induced bias in selecting the syllable.

Mismatch negativity (MMN) to speech sounds is modulated systematically by manual grip execution

“…Previously, we found that syllables (presented either auditorily, audiovisually or visually) are more likely categorized as [ke] when preparing a power grip and as [te] when preparing a precision grip [11]. We were, however, unable to determine whether perceptual processes were also affected.…”

“…We have also shown that the above-discussed articulation-grip connection works in a syllable categorization task [11]. In this study, participants were asked to prepare a power or a precision grip and then observe a noise-masked syllable.…”

“…Due to the explorative nature of the study, we did not have specific hypotheses about how the MMN amplitude would be affected by the different grips. We speculate that since the precision grip is associated with [te] [6,11], the precision grip performance boosts the processing of standard [ The asymmetries in the interaction could be also interpreted from another perspective. The difference between [ke] and [te] was significant for the precision grip but not for the power grip.…”

“…visual speech), the question arises whether it could be influenced by other non-auditory means as well. As our previous study showed that grip actions can influence speech categorization [11], we hypothesized that grip execution could also specifically modulate MMN to speech stimuli when the grips are 5 associated with the speech stimuli. If this modulation could be observed, it would show for the first time that action-related processes modulate MMN patterns, and it would also strongly support the notion that manual actions interact with speech processing at an early stage and thus can influence the perceptual outcome.…”

“…If this modulation could be observed, it would show for the first time that action-related processes modulate MMN patterns, and it would also strongly support the notion that manual actions interact with speech processing at an early stage and thus can influence the perceptual outcome. We used syllables [te] and [ke] as stimuli since they have been shown to be robustly associated with the precision and power grip, respectively [6,11]. We employed a classic oddball paradigm, where one syllable (e.g.…”