Holistic Processing in Speech Perception: Experts' and Novices' Processing of Isolated Cantonese Syllables

Holistic Processing in Speech Perception: Experts’ and Novices’ Processing of Isolated Cantonese Syllables Tianyin Liu (kanalty@hku.hk) Janet Hui-wen Hsiao (jhsiao@hku.hk) Department of Psychology, University of Hong Kong 627 Jockey Club Tower, Centennial Campus, Pokfulam Road, Hong Kong SAR Abstract recognized as a whole (Gauthier & Tanaka, 2002), and the more holistic they are, the better they can recognize/individualize faces or objects of expertise (Richler, Cheung, & Gauthier, 2011). Holistic processing is an expertise marker in visual perception. Here we tested participants’ perception of Cantonese syllables through composite paradigm commonly used for measuring holistic processing in vision research. We found that participants were more holistic in processing syllable initials than finals, possibly because initials are shorter and more easily combined with neighboring segments. More importantly, experts’ perception of syllable initials was strongly affected by finals (i.e., holistic processing), even when the initials were separated or disconnected from finals; whereas in novices, holistic processing gradually decreased with segment separation and disconnection. As for syllable final perception, experts were strongly influenced by initials, yet not when the segments were separated/disconnected. In contrast, novices showed little holistic processing in all conditions. These results showed that experts’ perception of syllable parts were more influenced by neighboring segments, suggesting that holistic processing may also be an expertise marker in auditory perception. Figure 1. The composite face illusion: a) 5 physically identical top face halves are perceived as different when aligned with 5 different bottom halves; but b) are perceived as the same when misaligned (images taken from Rossion, Keywords: holistic processing, speech perception, isolated Cantonese syllable processing. In contrast to the abundant literature on holistic processing in visual perception, it remains unclear whether a similar phenomenon also exists in auditory perception, and whether it is a hallmark in expert auditory processing. Our sense of hearing begins to develop since infancy or even the fetal period, much earlier than vision (Hepper & Shahidullah, 1994). The auditory system enables us not only to hear, but also to perceive and interpret sound information. The ability to recognize a caregiver’s voice and understand what he/she says is as important as the ability to recognize his/her face in the early years of development. It is also an essential tool for later learning, language development, and social interaction (Bellis, 2003; Clark, 2008; Sharma, Purdy, & Kelly, 2009). Hence, it is important to investigate what signals the expertise of auditory processing, especially in the perception of speech. Past research in speech perception has been focusing on phonological awareness, i.e., explicit awareness of the phonological structure of the language, and revealed its critical role in children’s acquisition of reading, in both alphabetic languages (Goswami & Mead, 1992), and logographic languages such as Chinese (Shu, Peng, & McBride-Chang, 2008; although it remains controversial; see Huang & Hanley, 1995). However the maturation of phonological awareness with age and training does not necessarily lead to a better ability to selectively attend to parts in speech perception without being interfered by irrelevant parts; in other words, phonological awareness does not necessarily signal analytical processing (reduced Introduction Holistic processing, i.e., gluing features into a gestalt and perceive them as a whole, has been identified as a hallmark of expertise in the perception of faces (Tanaka & Farah, 1993). The most prominent demonstration of holistic face processing is the composite illusion. Participants were shown two composite faces and asked to do same/different judgments about the top halves of the faces and ignore the irrelevant bottom halves. People reported two identical top halves to look different when they were aligned with two different bottom halves. This illusion disappeared when the top and bottom halves were misaligned (Hole, 1994; Fig. 1). Presumably, holistic processing binds the two halves of the faces together so that experts’ flexibility to access the information of individual parts is attenuated (Maurer, LeGrand, & Mondloch, 2002). Thus, they get interference from the irrelevant halves in the same/different judgments of the attended halves, and the amount of interference indicates holistic processing. The same paradigm has been applied to the recognition of many other non-face objects, such as cars (Gauthier, Curran, Curby, & Collins, 2003), fingerprints (Busey & Vanderkolk, 2005), and greebles (an artificial stimulus type, Gauthier & Tarr, 1997), and holistic processing has been found to indicate perceptual expertise with these objects. In experts’ eyes, parts are integrated and