Perceptual Reorganization of Lexical Tones: Effects of Age and Experimental Procedure

Abstract

Findings on the perceptual reorganization of lexical tones are mixed. Some studies report good tone discrimination abilities for all tested age groups, others report decreased or enhanced discrimination with increasing age, and still others report U-shaped developmental curves. Since prior studies have used a wide range of contrasts and experimental procedures, it is unclear how specific task requirements interact with discrimination abilities at different ages. In the present work, we tested German and Cantonese adults on their discrimination of Cantonese lexical tones, as well as German-learning infants between 6 and 18 months of age on their discrimination of two specific Cantonese tones using two different types of experimental procedures. The adult experiment showed that German native speakers can discriminate between lexical tones, but native Cantonese speakers show significantly better performance. The results from German-learning infants suggest that 6- and 18-month-olds discriminate tones, while 9-month-olds do not, supporting a U-shaped developmental curve. Furthermore, our results revealed an effect of methodology, with good discrimination performance at 6 months after habituation but not after familiarization. These results support three main conclusions. First, habituation can be a more sensitive procedure for measuring infants' discrimination than familiarization. Second, the previous finding of a U-shaped curve in the discrimination of lexical tones is further supported. Third, discrimination abilities at 18 months appear to reflect mature perceptual sensitivity to lexical tones, since German adults also discriminated the lexical tones with high accuracy.

Perceptual Narrowing in Speech and Face Recognition: Evidence for Intra-individual Cross-Domain Relations

“…Agreeing with previous research, our results confirmed that 9-month-old monolingual infants were not able to discriminate between non-native tones ( Mattock and Burnham, 2006 ; Yeung et al, 2013 ; Götz et al, 2018 ), or between other-race faces to which they had no prior exposure ( Kelly et al, 2007 , 2009 ).…”

“…The duration of each individual tone was 40 ms. For each trial, each tone was presented repeatedly with 1 s intervals between repetitions at a volume of 75 dB for the duration of the trial. A previous study had shown perceptual narrowing for exactly these stimuli in German infants between 6 and 9 months (see Götz et al, 2018 for more details).…”

“…In speech, very young infants can discriminate all kinds of speech sound contrasts but this sensitivity declines for many non-native sound contrasts within the first year of life (e.g., Werker and Tees , 1984 ; Höhle et al, 2009 ) and increases for native contrasts (e.g., Kuhl et al, 2006 ). Such perceptual narrowing may arise for vowels (around 6 months; e.g., Polka and Werker, 1994 ), consonants (around 10–12 months, e.g., Werker and Tees, 1984 ), and prosodic properties like lexical tone contrasts (between 6 and 9 months: e.g., Mattock and Burnham, 2006 ; Yeung et al, 2013 ; Götz et al, 2018 ) or word stress ( Höhle et al, 2009 ).…”

Protracted Development on Native Tone Interpretation: Evidence From Mandarin-Learning Infants’ Novel Word Learning

“…Dutch-exposed infants demonstrate a discrimination of Mandarin tone contrasts only during two specific periods of age: 5–6 and 17–18 months, but a decline in tone sensitivity between 5 and 18 months (Liu and Kager, 2014). German-learning infants, who discriminate Cantonese lexical tones at 6 and 18 months of age, fail at 9 months (Götz et al, 2018). Generally, non-tonal language learners demonstrate a U-shape development: a perceptual decrease followed by a rebound during the first 2 years of age, in tonal contrasts.…”

How Do Infants Disaggregate Referential and Affective Pitch?

“…Yet several studies suggest infants discover the presence/absence of lexical tones before their first birthday. Tone-learning infants retain their initial ability to discriminate tones, while infants exposed to a non-tone language lose it between 6 and 9 months (Mattock and Burnham, 2006 ; Mattock et al, 2008 ; Yeung et al, 2013 ; Liu and Kager, 2014 ; Götz et al, 2018 ), before losing the ability to learn tone-to-word associations, which they still possess at 9 months (Yeung et al, 2014 ), by 18 months (Singh et al, 2014 ; Hay et al, 2015 ; Burnham et al, 2018 ; Liu and Kager, 2018 ). How are infants able to disaggregate pitch into non-referential affective and referential linguistic information?…”