How robust are exemplar effects in word comprehension?

Abstract

This paper studies the robustness of exemplar effects in word comprehension by means of four long-term priming experiments with lexical decision tasks in Dutch. A prime and target represented the same word type and were presented with the same or different degree of reduction. In Experiment 1, participants heard only a small number of trials, a large proportion of repeated words, and stimuli produced by only one speaker. They recognized targets more quickly if these represented the same degree of reduction as their primes, which forms additional evidence for the exemplar effects reported in the literature. Similar effects were found for two speakers who differ in their pronunciations. In Experiment 2, with a smaller proportion of repeated words and more trials between prime and target, participants recognized targets preceded by primes with the same or a different degree of reduction equally quickly. Also, in Experiments 3 and 4, in which listeners were not exposed to one but two types of pronunciation variation (reduction degree and speaker voice), no exemplar effects arose. We conclude that the role of exemplars in speech comprehension during natural conversations, which typically involve several speakers and few repeated content words, may be smaller than previously assumed.Keywords: speech comprehension, exemplar effects, pronunciation variation, acoustic reduction 3 Several models of speech comprehension assume that the mental lexicon stores the pronunciation of a word with two types of representations, namely abstract representations and exemplars (e.g., Goldinger, 2007;McLennan, Luce, and Charles-Luce, 2003). Abstract representations are strings of sound symbols like phonemes or phonological features, which only contain information about acoustic properties that distinguish between these symbols. In contrast, clouds of exemplars represent many occurrences of words that the language user has uttered or heard. Each exemplar is a detailed representation corresponding to the speech signal of one occurrence and thus contains subtle acoustic information, for example about the word's exact pronunciation or the speaker's voice. 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. Most experiments showed...

On the locus of talker-specificity effects in spoken word recognition: an ERP study with dichotic priming

“…The challenge now for future work is to better understand the origin of the influences related to talker-specific information. Taking into account recent studies (Hanique et al, 2013;Nijveld et al, 2016), we suggest that talkerspecific effects might result from the interactions between two memory systems, namely episodic memory and the mental lexicon. Given that hemispheric differences in the processing of talker-specific information have been revealed in prior research (e.g.…”

“…No evidence for an influence of talker specific information was observed during lexical activation, and it is rather hard to envisage, within a hybrid view of the mental lexicon, that talker-specific representations does not come into play at the stage of lexical activation. Recent studies (Hanique, Aalders & Ernestus, 2013;Nijveld, Mulder, Bosch & Ernestus, 2016) question hybrid models of spoken word recognition and argue that talker-specificity effects have little to do with the mental lexicon, instead they would engage detailed representations stored in episodic memory. Our observation that the talker-specific effect is modulated by word frequency, an effect that indexes some form of lexical activation, seems to indicate that our effects are driven at least in part by the lexical representations.…”

Reduced speech: All is variability

“…Reduced speech is well known to raise questions for spoken word recognition and for what form(s) of words are represented in the lexicon (Brouwer, Mitterer, & Hüttig, ; Hanique, Aalders, & Ernestus, ; Nijveld, ten Bosch, & Ernestus, ). One approach is to assume all possible forms of a word are listed in the lexicon, perhaps as exemplars of tokens heard in the past, including the widely variable reduced tokens one has heard.…”