Winston D. Goh

Talker Variability and Recognition Memory: Instance-Specific and Voice-Specific Effects.

The author investigated voice context effects in recognition memory for words spoken by multiple talkers by comparing performance when studied words were repeated with same, different, or new voices at test. Hits and false alarms increased when words were tested with studied voices compared with unstudied voices. Discrimination increased only when the exact same voice was used. A trend toward conservatism in response bias was observed when test words switched to increasingly unfamiliar voices. Taken together, the overall findings suggest that the voice-specific attributes of individual talkers are preserved in long-term memory. Implications for the role of instance-specific matching and voice-specific familiarity processes and the nature of spoken-word representation are discussed.

Testing the myth of the encoding–retrieval match

The view that successful memory performance depends importantly on the extent to which there is a match between the encoding and retrieval conditions is commonplace in memory research. However, Nairne (Memory, 10, 389–395, 2002) proposed that this idea about trace–cue compatibility being the driving force behind memory retention is a myth, because one cannot make unequivocal predictions about performance by appealing to the encoding–retrieval match. What matters instead is the relative diagnostic value of the match, and not the absolute match. Three experiments were carried out in which participants memorised word pairs and tried to recall target words when given retrieval cues. The diagnostic value of the cue was varied by manipulating the extent to which the cues subsumed other memorised words and the level of the encoding–retrieval match. The results supported Nairne’s (Memory, 10, 389–395, 2002) assertion that the diagnostic value of retrieval cues is a better predictor of memory performance than the absolute encoding–retrieval match.

Multimodal perceptual organization of speech: evidence from tone analogs of spoken utterances

Theoretical and practical motives alike have prompted recent investigations of multimodal speech perception. Theoretically, multimodal studies have extended the conceptualization of perceptual organization beyond the familiar modality-bound accounts deriving from Gestalt psychology. Practically, such investigations have been driven by a need to understand the proficiency of multimodal speech perception using an electrocochlear prosthesis for hearing. In each domain, studies have shown that perceptual organization of speech can occur even when the perceivers auditory experience departs from natural speech qualities. Accordingly, our research examined auditor-visual multimodal integration of videotaped faces and selected acoustic constituents of speech signals, each realized as a single sinewave tone accompanying a video image of an articulating face. The single tone reproduced the frequency and amplitude of the phonatory cycle or of one of the lower three oral formants. Our results showed a distinct advantage for the condition pairing the video image of the face with a sinewave replicating the second formant, despite its unnatural timbre and its presentation in acoustic isolation from the rest of the speech signal. Perceptual coherence of multimodal speech in these circumstances is established when the two modalities concurrently specify the same underlying phonetic attributes.

Distributional analyses in auditory lexical decision: neighborhood density and word-frequency effects.

In the present article, the effects of phonological neighborhood density and word frequency in spoken word recognition were examined using distributional analyses of response latencies in auditory lexical decision. A density × frequency interaction was observed in mean latencies; frequency effects were larger for low-density words than for high-density words. Distributional analyses further revealed that for low-density words, frequency effects were reflected in both distributional shifting and skewing, whereas for high-density words, frequency effects were purely mediated by distributional skewing. The results suggest that word frequency plays a role in early auditory word recognition only when there is relatively little competition between similar-sounding words, and that frequency effects in high-density words reflect postlexical checking.

Effects of lexical competition on immediate memory span for spoken words.

Abstract Current theories and models of the structural organization of verbal short-term memory are primarily based on evidence obtained from manipulations of features inherent in the short-term traces of the presented stimuli, such as phonological similarity. In the present study, we investigated whether properties of the stimuli that are not inherent in the short-term traces of spoken words would affect performance in an immediate memory span task. We studied the lexical neighbourhood properties of the stimulus items, which are based on the structure and organization of words in the mental lexicon. The experiments manipulated lexical competition by varying the phonological neighbourhood structure (i.e., neighbourhood density and neighbourhood frequency) of the words on a test list while controlling for word frequency and intra-set phonological similarity (family size). Immediate memory span for spoken words was measured under repeated and nonrepeated sampling procedures. The results demonstrated that lexical competition only emerged when a nonrepeated sampling procedure was used and the participants had to access new words from their lexicons. These findings were not dependent on individual differences in short-term memory capacity. Additional results showed that the lexical competition effects did not interact with proactive interference. Analyses of error patterns indicated that item-type errors, but not positional errors, were influenced by the lexical attributes of the stimulus items. These results complement and extend previous findings that have argued for separate contributions of long-term knowledge and short-term memory rehearsal processes in immediate verbal serial recall tasks.

Observing neighborhood effects without neighbors

With a new metric called phonological Levenshtein distance (PLD20), the present study explores the effects of phonological similarity and word frequency on spoken word recognition, using polysyllabic words that have neither phonological nor orthographic neighbors, as defined by neighborhood density (the N-metric). Inhibitory effects of PLD20 were observed for these lexical hermits: Close-PLD20 words were recognized more slowly than distant PLD20 words, indicating lexical competition. Importantly, these inhibitory effects were found only for low- (not high-) frequency words, in line with previous findings that phonetically related primes inhibit recognition of low-frequency words. These results indicate that the properties of PLD20—a continuous measure of word-form similarity—make it a promising new metric for quantifying phonological distinctiveness in spoken word recognition research.

Audio-visual perception of sinewave speech in an adult cochlear implant user: A case study

Objective The purpose of this case study was to investigate multimodal perceptual coherence in speech perception in an exceptionally good postlingually deafened cochlear implant user. His ability to perceive sinewave replicas of spoken sentences, and the extent to which he integrated sensory information from multimodal sources was compared with a group of adult normal-hearing listeners to determine the contribution of natural auditory quality in the use of electrocochlear stimulation. Design The patient, “Mr. S,” transcribed sinewave sentences of natural speech under audio-only (AO), visual-only (VO), and audio-visual (A+V) conditions. His performance was compared with the data collected from 25 normal-hearing adults. Results Although normal-hearing participants performed better than Mr. S for AO sentences (65% versus 53% syllables correct), Mr. S was superior for VO sentences (43% versus 18%). For A+V sentences, Mr. S’s performance was comparable with the normal-hearing group (90% versus 86%). An estimate of the amount of visual enhancement, R, obtained from seeing the talker’s face showed that Mr. S derived a larger gain from the additional visual information than the normal-hearing controls (78% versus 59%). Conclusions The findings from this case study of an exceptionally good cochlear implant user suggest that he is perceiving the sinewave sentences on the basis of coherent variation from multimodal sensory inputs, and not on the basis of lipreading ability alone. Electrocochlear stimulation is evidently useful in multimodal contexts because it preserves dynamic speech-like variation, despite the absence of speech-like auditory qualities.

Semantic Richness Effects in Spoken Word Recognition: A Lexical Decision and Semantic Categorization Megastudy

A large number of studies have demonstrated that semantic richness dimensions [e.g., number of features, semantic neighborhood density, semantic diversity , concreteness, emotional valence] influence word recognition processes. Some of these richness effects appear to be task-general, while others have been found to vary across tasks. Importantly, almost all of these findings have been found in the visual word recognition literature. To address this gap, we examined the extent to which these semantic richness effects are also found in spoken word recognition, using a megastudy approach that allows for an examination of the relative contribution of the various semantic properties to performance in two tasks: lexical decision, and semantic categorization. The results show that concreteness, valence, and number of features accounted for unique variance in latencies across both tasks in a similar direction—faster responses for spoken words that were concrete, emotionally valenced, and with a high number of features—while arousal, semantic neighborhood density, and semantic diversity did not influence latencies. Implications for spoken word recognition processes are discussed.

Articulation effects in melody recognition memory.

Various surface features—timbre, tempo, and pitch—influence melody recognition memory, but articulation format effects, if any, remain unknown. For the first time, these effects were examined. In Experiment 1, melodies that remained in the same, or appeared in a different but similar, articulation format from study to test were recognized better than were melodies that were presented in a distinct format at test. A similar articulation format adequately induced matching processes to enhance recognition. Experiment 2 revealed that melodies rated as perceptually dissimilar on the basis of the location of the articulation mismatch did not impair recognition performance, suggesting an important boundary condition for articulation format effects on memory recognition—the matching of the memory trace and recognition probe may depend more on the overall proportion, rather than the temporal location, of the mismatch. The present findings are discussed in terms of a global matching advantage hypothesis.

The roles of semantic similarity and proactive interference in the word length effect

We examined the influence of semantic similarity and proactive interference (PI) on the word length effect (WLE) in immediate serial recall. Word length was manipulated by comparing memory for monosyllabic versus multisyllabic words. PI effects were evaluated by manipulating semantic similarity in the to-be-remembered lists and examining its impact on the WLE’s magnitude across eight-trial blocks. Words were sampled from a single semantic category across the entire block, from a single category within the list, or from different categories. Robust WLEs were observed in single-category blocks and when words were from different categories. However, when all the within-list words were from the same semantic category, the WLE was sharply attenuated. Except for the within-list semantic similarity condition, there was a buildup in PI levels in the form of protrusion errors across trials. However, the magnitude of the WLE did not increase with the PI buildup, suggesting that it was not affected by PI across trials.