Abstract
Previous studies suggest fundamental differences between the perceptual learning of speech and non-speech stimuli. One major difference is in the way variability in the training set affects learning and its generalization to untrained stimuli: training-set variability appears to facilitate speech learning, while slowing or altogether extinguishing non-speech auditory learning. We asked whether the reason for this apparent difference is a consequence of the very different methodologies used in speech and non-speech studies. We hypothesized that speech and non-speech training would result in a similar pattern of learning if they were trained using the same training regimen. We used a 2 (random vs. blocked pre- and post-testing) × 2 (random vs. blocked training) × 2 (speech vs. non-speech discrimination task) study design, yielding 8 training groups. A further 2 groups acted as untrained controls, tested with either random or blocked stimuli. The speech task required syllable discrimination along 4 minimal-pair continua (e.g., bee-dee), and the non-speech stimuli required duration discrimination around 4 base durations (e.g., 50 ms). Training and testing required listeners to pick the odd-one-out of three stimuli, two of which were the base duration or phoneme continuum endpoint and the third varied adaptively. Training was administered in 9 sessions of 640 trials each, spread over 4–8 weeks. Significant learning was only observed following speech training, with similar learning rates and full generalization regardless of whether training used random or blocked schedules. No learning was observed for duration discrimination with either training regimen. We therefore conclude that the two stimulus classes respond differently to the same training regimen. A reasonable interpretation of the findings is that speech is perceived categorically, enabling learning in either paradigm, while the different base durations are not well-enough differentiated to allow for categorization, resulting in disruption to learning.
Highlights
Despite decades of research in perceptual learning, it is not clear whether the perceptual learning of the acoustic elements of speech [1] and non-speech [2, 3] sounds are based on the same underlying mechanisms
The perceptual learning of non-speech acoustic elements is most often studied with training regimens that involve massive repetition of the same stimulus tokens throughout training (e.g., [5, 6])
The major outcomes of the current study were that (1) the discrimination of minimal phonetic contrasts was learned with random and blocked training regimens; (2) speech learning with either one of the regimens fully generalized to the other; (3) no learning was observed on the duration discrimination task with either a random or a blocked training regimen
Summary
Despite decades of research in perceptual learning, it is not clear whether the perceptual learning of the acoustic elements of speech [1] and non-speech [2, 3] sounds are based on the same underlying mechanisms These two forms of perceptual learning were generally studied separately, by different communities of investigators with greatly varying goals and methodologies. The perceptual learning of non-speech acoustic elements is most often studied with training regimens that involve massive repetition of the same stimulus tokens throughout training (e.g., [5, 6]). The perceptual learning of speech was predominantly studied with regimens that involve little or no stimulus repetition throughout training [9, 10]. Three specific hypotheses derived from this idea were tested in this study: H1: Randomly varying the stimuli along a training-relevant dimension and presenting them in blocks (keeping them constant on a trial-by-trial basis) will result in similar amounts of learning
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
