Top-down linguistic categories dominate over bottom-up acoustics in lexical tone processing

Abstract

Native tonal-language speakers exhibit reduced sensitivity to lexical tone differences within categories when compared to across categories (i.e., a top-down linguistic influence). However, increasing evidence suggests enhanced sensitivities to lexical tones among musically trained individuals (bottom-up influence), though previous studies examined non-tonal language speakers processing lexical tones. We investigated the relative contribution of top-down and bottom-up processing of lexical tones when both strategies are available. Seventeen native Mandarin speakers with extensive musical training completed a music test and a lexical tone discrimination task. The music test validated their enhanced pitch-processing abilities. The lexical tone discrimination task measured participants’ lexical tone sensitivities along a continuum. Results were compared to existing data from Mandarin non-musicians and English speaking musicians (Zhao & Kuhl, 2012). Despite their enhanced bottom-up pitch processing, Mandarin musicians’ performance exhibited patterns similar to Mandarin non-musicians, reflecting the dominant influence of linguistic categories (p = 0.504). Their sensitivities were also lower than English-speaking musicians (p = 0.011). However, further regression analysis suggests that bottom-up processing still plays a role in Mandarin musicians: their within-category tone discrimination is predicted by their musical pitch discrimination scores, similar to English musicians but opposite Mandarin non-musicians.