On building models of spoken-word recognition: When there is as much to learn from natural “oddities” as artificial normality

Abstract

Speech scientists have long known that speech perfection is a fiction. Everyday speech is complex, variable, and, ultimately, elusive. Although attempts have been made to test spoken-word recognition models with every day speech (e.g., Bard, Sotillo, Kelly, & Aylett, 2001;Kemps, Ernestus, Schreuder, & Baayen, 2004;McAllister, 1991;Mehta & Cutler, 1988), such studies are in a minority. There are two main reasons for this. First, studying conversational speech, by definition, limits the amount of experimental control one has over the input. Studying laboratory speech maximizes such control-for better or for worse. Second, attempting to define the concept of conversational speech itself opens a can of worms, because speech styles vary along quasiorthogonal dimensions, such as spontaneity (e.g., read, rehearsed, unscripted), articulatory effort (e.g., hyper-articulated, hypo-articulated), situation (e.g., monologue, dialogue), source (e.g., healthy speaker, dysarthric speaker), and so forth. These speech styles differ in the extent to which they contain the quantity and quality of acoustic cues available in carefully articulated laboratory speech, such as vowel reduction or phoneme elision/ assimilation (cf. Duez, 1995;Hawkins, 2003;Hawkins & Smith, 2001;Tiffany, 1959;Uchanski, 2005), which makes the selection of stimuli for perceptual experiments rather arbitrary. For these reasons, the investigation of spoken-word recognition has traditionally relied on either carefully articulated speech produced in the laboratory or (re)synthesized speech. Artificial NormalityPerceptual studies using tightly controlled laboratory speech have been successful in establishing key constructs for models of spoken-word recognition, such as lexical competition, bottom-up versus top-down flow, uniqueness point, and episodic versus abstract lexical representations. Yet the external validity of such constructs remains debatable. For instance, the finding that a word can be identified as soon as the sensory input makes it uniquely distinguishable from its competitors (see, e.g., misdem for misdemeanor) has been used to support the claim that lexical candidates are activated sequentially as the signal unfolds (e.g., Grosjean, 1980;Marslen-Wilson, 1987 Much of what we know about spoken-word recognition comes from studies relying on speech stimuli either carefully produced in the laboratory or computer altered. Although such stimuli have allowed key constructs to be highlighted, the extent to which these constructs are operative in the processing of everyday speech is unclear. We argue that studying the recognition of naturally occurring degraded speech, such as that produced by individuals with neurological disease, can improve the external validity of existing spoken-word recognition models. This claim is illustrated in an experiment on the effect of talker-specific (indexical) variations on lexical access. We found that talker specificity effects, wherein words are better recalled if played in the same voice than in a different voice betwe...

How robust are exemplar effects in word comprehension?

“…Hence, exemplar effects can be found for very different speakers. Our results appear to contrast with those obtained by Mattys and Liss (2008), who found that the size of exemplar effects depends on the level of intelligibility of the speakers: Participants who listened to dysarthric speakers showed longer response times and larger exemplar effects. Following McLennan and Luce (2005), the authors argue that exemplar effects are larger if performance latencies are longer.…”

“…This experiment showed a clear exemplar effect: responses were faster to targets that represented the same pronunciation variant as their primes. In contrast to earlier studies (e.g., Mattys and Liss, 2008;McLennan et al, 2003;McLennan and Luce, 2005;Palmeri et al, 1993), in our experiments, primes and targets were always different recordings, even when they represented the same pronunciation variant produced by the same speaker. The results of Experiment 1 thus show that even if the target is not completely identical to the prime, its processing can be facilitated by the exemplar formed by its prime.…”

“…Exemplar effects have been established in several priming experiments (e.g., Bradlow, Nygaard, and Pisoni, 1999;Craik and Kirsner, 1974;Goh, 2005;Goldinger, 1996;Janse, 2008;Mattys and Liss, 2008;McLennan et al, 2003;McLennan and Luce, 2005;Palmeri, Goldinger, and Pisoni, 1993).…”

“…Many articles in the literature point to a role of exemplars in word comprehension. This study investigates the robustness of these exemplar effects.Exemplar effects have been established in several priming experiments (e.g., Bradlow, Nygaard, and Pisoni, 1999;Craik and Kirsner, 1974;Goh, 2005;Goldinger, 1996;Janse, 2008;Mattys and Liss, 2008;McLennan et al, 2003;McLennan and Luce, 2005;Palmeri, Goldinger, and Pisoni, 1993).These experiments contained repeated words and the comprehension of the second occurrence of a word (the target) is expected to be facilitated by the first occurrence (the prime). Primes and targets were completely identical, that is the same token, or they differed in speech rate, time-compression, the realization of a certain segment (e.g., intervocalic /t,d/ produced as [t,d] or as a flap in American English), or the speaker's voice.…”

Examining the Effects of Variation in Emotional Tone of Voice on Spoken Word Recognition

“…Further research has supported the time-course hypothesis (however, see Orfanidou, Davis, Ford, & Marslen-Wilson, 2011). First, Mattys and Liss (2008) found that specificity effects emerged when participants responded slowly to degraded dysar thritic speech, but not when participants responded quickly to speech produced by healthy individuals. Second, Vitevitch and Donoso (2011) recently found that participants detected a change in talkers less often (i.e., a greater occurrence of change deafness) in an easy lexical decision task when responding quickly.…”