Voice-specificity effects on auditory word priming

This research explores the nature of the memory traces that support spoken word identification. Specifically, do voice-specificity effects in implicit memory depend on information in a perceptual representational system or, alternatively, on the similarity of study and test exemplars? Memory for words and voices was assessed with two perceptual identification tests—the identification of words in noise and the identification of low-pass filtered words—after two encoding conditions (identification of words in noise and of words in the clear). At test, a word was presented in the same voice as at study or in a different voice. The data from the two experiments showed that study-to-test changes in voice reduced priming and that voice-specificity effects were greatest when the type of processing engaged at study overlapped with that required at test. Taken together, the results implicate the goodness of the processing match between encoding and test as the primary determinant of voice-specificity effects on perceptual identification tests and support the hypothesis that both voice and word information is represented within a single episodic memory system.     

Effects of talker, rate, and amplitude variation on recognition memory for spoken words

This study investigated the encoding of the surface form of spoken words using a continuous recognition memory task. The purpose was to compare and contrast three sources of stimulus variability--talker, speaking rate, and overall amplitude--to determine the extent to which each source of variability is retained in episodic memory. In Experiment 1, listeners judged whether each word in a list of spoken words was "old" (had occurred previously in the list) or "new." Listeners were more accurate at recognizing a word as old if it was repeated by the same talker and at the same speaking rate; however, there was no recognition advantage for words repeated at the same overall amplitude. In Experiment 2, listeners were first asked to judge whether each word was old or new, as before, and then they had to explicitly judge whether it was repeated by the same talker, at the same rate, or at the same amplitude. On the first task, listeners again showed an advantage in recognition memory for words repeated by the same talker and at same speaking rate, but no advantage occurred for the amplitude condition. However, in all three conditions, listeners were able to explicitly detect whether an old word was repeated by the same talker, at the same rate, or at the same amplitude. These data suggest that although information about all three properties of spoken words is encoded and retained in memory, each source of stimulus variation differs in the extent to which it affects episodic memory for spoken words.     

Audiovisual speech facilitates voice learning

In this research, we investigated the effects of voice and face information on the perceptual learning of talkers and on long-term memory for spoken words. In the first phase, listeners were trained over several days to identify voices from words presented auditorily or audiovisually. The training data showed that visual information about speakers enhanced voice learning, revealing cross-modal connections in talker processing akin to those observed in speech processing. In the second phase, the listeners completed an auditory or audiovisual word recognition memory test in which equal numbers of words were spoken by familiar and unfamiliar talkers. The data showed that words presented by familiar talkers were more likely to be retrieved from episodic memory, regardless of modality. Together, these findings provide new information about the representational code underlying familiar talker recognition and the role of stimulus familiarity in episodic word recognition.     

Vocal emotions influence verbal memory: Neural correlates and interindividual differences

Past research has identified an event-related potential (ERP) marker for vocal emotional encoding and has highlighted vocal-processing differences between male and female listeners. We further investigated this ERP vocal-encoding effect in order to determine whether it predicts voice-related changes in listeners’ memory for verbal interaction content. Additionally, we explored whether sex differences in vocal processing would affect such changes. To these ends, we presented participants with a series of neutral words spoken with a neutral or a sad voice. The participants subsequently encountered these words, together with new words, in a visual word recognition test. In addition to making old/new decisions, the participants rated the emotional valence of each test word. During the encoding of spoken words, sad voices elicited a greater P200 in the ERP than did neutral voices. While the P200 effect was unrelated to a subsequent recognition advantage for test words previously heard with a neutral as compared to a sad voice, the P200 did significantly predict differences between these words in a concurrent late positive ERP component. Additionally, the P200 effect predicted voice-related changes in word valence. As compared to words studied with a neutral voice, words studied with a sad voice were rated more negatively, and this rating difference was larger, the larger the P200 encoding effect was. While some of these results were comparable in male and female participants, the latter group showed a stronger P200 encoding effect and qualitatively different ERP responses during word retrieval. Estrogen measurements suggested the possibility that these sex differences have a genetic basis.     

Selective attention in perceptual adjustments to voice

The effects of perceptual adjustments to voice information on the perception of isolated spoken words were examined. In two experiments, spoken target words were preceded or followed within a trial by a neutral word spoken in the same voice or in a different voice as the target. Over-all, words were reproduced more accurately on trials on which the voice of the neutral word matched the voice of the spoken target word, suggesting that perceptual adjustments to voice interfere with word processing. This result, however, was mediated by selective attention to voice. The results provide further evidence of a close processing relationship between perceptual adjustments to voice and spoken word recognition.     

Specificity of memory representations for spoken words

Many theories of spoken word recognition assume that lexical items are stored in memory as abstract representations. However, recent research (e.g., Goldinger, 1996) has suggested that representations of spoken words in memory are veridical exemplars that encode specific information, such as characteristics of the talker’s voice. If representations are exemplar based, effects of stimulus variation such as that arising from changes in the identity of the talker may have an effect on identification of and memory for spoken words. This prediction was examined for an implicit and explicit task (lexical decision and recognition, respectively). Comparable amounts of repetition priming in lexical decision were found for repeated words, regardless of whether the repetitions were in the same or in different voices. However, reaction times in the recognition task were faster if the repetition was in the same voice. These results suggest a role for both abstract and specific representations in models of spoken word recognition.     

Surface form typicality and asymmetric transfer in episodic memory for spoken words

A series of experiments was conducted to determine whether the typicality of the surface form of speech would affect memory retention of spoken words. For each surface characteristic studied, a continuous-recognition-memory task was used in which listeners based recognition judgments on word identity alone. For "typical" items, repetition benefits did not depend on whether the surface forms of the 1st and 2nd occurrences matched or mismatched. For "atypical" items, a larger repetition benefit occurred when the surface forms of the 2 occurrences matched. These results suggest that episodic memory for spoken words may be directly related to the perceived typicality of particular surface characteristics.     

Limitations of episodic memory for highly similar auditory stimuli

Two experiments investigated participants’ recognition memory for word content, while varying vocal characteristics, and for vocal characteristics alone. In Experiment 1, participants performed an auditory recognition task in which they identified whether a spoken word was “new”, “old” (repeated word, repeated voice), or “similar” (repeated word, new voice). Results showed that word recognition accuracy was lower for similar trials than old trials. In Experiment 2, participants performed an auditory recognition task in which they identified whether or not a phrase was spoken in an old or new voice, with repetitions occurring after a variable number of intervening stimuli. Results showed that recognition accuracy was lower when old voices spoke an alternate message than a repeated message and accuracy decreased as a function of number of intervening items. Overall, the results suggest that speech recognition is better for lexical content than vocal characteristics alone.     

Examining the effects of variation in emotional tone of voice on spoken word recognition

Emotional tone of voice (ETV) is essential for optimal verbal communication. Research has found that the impact of variation in nonlinguistic features of speech on spoken word recognition differs according to a time course. In the current study, we investigated whether intratalker variation in ETV follows the same time course in two long-term repetition priming experiments. We found that intratalker variability in ETVs affected reaction times to spoken words only when processing was relatively slow and difficult, not when processing was relatively fast and easy. These results provide evidence for the use of both abstract and episodic lexical representations for processing within-talker variability in ETV, depending on the time course of spoken word recognition.     

The effects of talker familiarity on spoken word identification in younger and older listeners

The present study was designed to examine age differences in the ability to use voice information acquired intentionally (Experiment 1) or incidentally (Experiment 2) as an aid to spoken word identification. Following both implicit and explicit voice learning, participants were asked to identify novel words spoken either by familiar talkers (ones they had been exposed to in the training phase) or by 4 unfamiliar voices. In both experiments, explicit memory for talkers' voices was significantly lower in older than in young listeners. Despite this age-related decline in voice recognition, however, older adults exhibited equivalent, and in some cases greater, benefit than young listeners from having words spoken by familiar talkers. Implications of the findings for age-related changes in explicit versus implicit memory systems are discussed.     

Perceptual and response components in repetition priming of spoken words and pseudowords

Two experiments explored repetition priming effects for spoken words and pseudowords in order to investigate abstractionist and episodic accounts of spoken word recognition and repetition priming. In Experiment 1, lexical decisions were made on spoken words and pseudowords with half of the items presented twice (～12 intervening items). Half of all repetitions were spoken in a “different voice” from the first presentations. Experiment 2 used the same procedure but with stimuli embedded in noise to slow responses. Results showed greater priming for words than for pseudowords and no effect of voice change in both normal and effortful processing conditions. Additional analyses showed that for slower participants, priming is more equivalent for words and pseudowords, suggesting episodic stimulus–response associations that suppress familiarity-based mechanisms that ordinarily enhance word priming. By relating behavioural priming to the time-course of pseudoword identification we showed that under normal listening conditions (Experiment 1) priming reflects facilitation of both perceptual and decision components, whereas in effortful listening conditions (Experiment 2) priming effects primarily reflect enhanced decision/response generation processes. Both stimulus–response associations and enhanced processing of sensory input seem to be voice independent, providing novel evidence concerning the degree of perceptual abstraction in the recognition of spoken words and pseudowords.     

Retrieval-based illusory recollections: Why study-test contextual changes impair source memory

Illusory source recollections can be manufactured purely by the conditions at retrieval. At encoding, individuals listened to words spoken by a male or a female voice and later, at retrieval, determined who initially had spoken the test word or whether it was a new word. In Experiment 1, individuals were instructed during the memory test to make a response of male or female only if they clearly recollected the speaker presenting the item during encoding and to respond don't remember otherwise. Presenting test words with the same voice (match condition) as the one that had presented the word at encoding, a different voice (mismatch condition), or no test voice had no effect on the rate of responding don't remember. Instead, matching and mismatching test voices created illusory recollections that were consistent with the test voice. Experiment 2 yielded similar results with a remember/know source test. In this article, a theory is proposed that explains the illusory recollection effects, and a multinomial model and procedure are used to separate and measure the contributions of source discrimination and illusory recollections to performance.     

Influences of spoken word planning on speech recognition

In 4 chronometric experiments, influences of spoken word planning on speech recognition were examined. Participants were shown pictures while hearing a tone or a spoken word presented shortly after picture onset. When a spoken word was presented, participants indicated whether it contained a prespecified phoneme. When the tone was presented, they indicated whether the picture name contained the phoneme (Experiment 1) or they named the picture (Experiment 2). Phoneme monitoring latencies for the spoken words were shorter when the picture name contained the prespecified phoneme compared with when it did not. Priming of phoneme monitoring was also obtained when the phoneme was part of spoken nonwords (Experiment 3). However, no priming of phoneme monitoring was obtained when the pictures required no response in the experiment, regardless of monitoring latency (Experiment 4). These results provide evidence that an internal phonological pathway runs from spoken word planning to speech recognition and that active phonological encoding is a precondition for engaging the pathway.     

Differential effects of cue dependency on item and source memory

The authors investigated the cue dependency of source and item memory. Individuals listened to words spoken by a man or a woman and later determined whether a test word was previously presented by a man or by a woman, or whether it was a new word. Cue dependent effects were assessed by presenting test words with (a) the same voice (match condition) that originally presented the word, (b) a different but familiar voice (mismatch condition), (c) a novel test voice (novel condition), and (d) no test voice (control condition). Compared with the control condition, source recollection was facilitated in matching-context conditions, disrupted in mismatching-context conditions, and not affected in novel test conditions. By contrast, item recognition was not affected by the match-mismatch manipulation but was significantly worse in novel test voice conditions. The authors propose an associative source interference view to account for the voice match-mismatch effects observed in source recollection.     

Communicating emotion: linking affective prosody and word meaning

The present study investigated the role of emotional tone of voice in the perception of spoken words. Listeners were presented with words that had either a happy, sad, or neutral meaning. Each word was spoken in a tone of voice (happy, sad, or neutral) that was congruent, incongruent, or neutral with respect to affective meaning, and naming latencies were collected. Across experiments, tone of voice was either blocked or mixed with respect to emotional meaning. The results suggest that emotional tone of voice facilitated linguistic processing of emotional words in an emotion-congruent fashion. These findings suggest that information about emotional tone is used in the processing of linguistic content influencing the recognition and naming of spoken words in an emotion-congruent manner.     

内隐与外显记忆编码阶段脑机制的重叠与分离

记忆包括编码和提取两个重要阶段, 以往研究多关注内隐和外显记忆在提取阶段的脑机制分离, 那二者在编码阶段的脑机制是否不同？为探讨这个问题, 该实验采用两阶段的迫选再认方式, 把学习项目区分成三类：随后被选择且告知为见过的项目(记住), 随后被选择但告知为猜测的项目 (启动)以及随后未被选择的项目(忘记)。结果表明, 从200 ms开始的颞区负走向Dm效应为内隐记忆(启动vs忘记)所特有, 反映了对刺激的知觉加工过程, 400~500 ms前额区正走向的Dm效应为外显记忆(记住vs忘记)所特有, 反映了对刺激的精细加工过程, 而200~300 ms中央区及600 ms开始的顶区负走向的Dm效应为两种记忆类型所共有, 它们分别反映了对刺激的注意状态以及把编码后的刺激信息登记进相应记忆系统的过程。因此, 内隐记忆与外显记忆在编码阶段的脑机制既存在着分离, 也存在着重叠的现象。     

Auditory recognition without identification

When visual recognition test items are unidentifiable--through fragmentation, for example--participants can discriminate between unidentifiable items that were presented recently and those that were not. The present study extends this recognition without identification phenomenon to the auditory modality. In several experiments, participants listened to words and were then presented with spoken recognition test items that were embedded in white noise. Participants attempted to identify each spoken word through the white noise, then rated the likelihood that the word was studied. Auditory recognition without identification was found: Participants discriminated between studied and unstudied words in the absence of an ability to identify them through white noise, even when the voice changed from male to female and when the study list was presented visually. The effect was also found when identification was hindered through the isolation of particular phonemes, suggesting that phoneme information may be present in memory traces for recently spoken words.     

Affective orientation influences memory for emotional and neutral words

Memory is better for emotional words than for neutral words, but the conditions contributing to emotional memory improvement are not entirely understood. Elsewhere, it has been observed that retrieval of a word is easier when its attributes are congruent with a property assessed during an earlier judgment task. The present study examined whether affective assessment of a word matters to its remembrance. Two experiments were run, one in which only valence assessment was performed, and another in which valence assessment was combined with a running recognition for list words. In both experiments, some participants judged whether each word in a randomized list was negative (negative monitoring), and others judged whether each was positive (positive monitoring). We then tested their explicit memory for the words via both free recall and delayed recognition. Both experiments revealed an affective congruence effect, such that negative words were more likely to be recalled and recognized after negative monitoring, whereas positive words likewise benefited from positive monitoring. Memory for neutral words was better after negative monitoring than positive monitoring.Thus, memory for both emotional and neutral words is contingent on one's affective orientation during encoding.     

Auditory registration without learning

In 3 studies, the authors explore how repeated exposure to a spoken word affects memory for perceptual attributes associated with the word (such as a talker's voice or a word's plurality). Subjects heard a list of words; particular words were repeated differing numbers of times. At test, subjects estimated the frequency of each word, with instructions to give frequency judgments of "zero" to words with changed attributes. The experiments demonstrate that memory for perceptual attributes improves very little after the first few repetitions, although word memory continues to improve. The experiments extend the registration without learning effect (D. L. Hintzman, T. Curran, & B. Oppy, 1992) to auditory words, to complex attributes (voice), and to conditions of low and high stimulus variability (two or many voices).     

Effects of hearing words, imaging hearing words, and reading on auditory implicit and explicit memory tests

In four experiments, we examined the degree to which imaging written words as spoken by a familiar talker differs from direct perception (hearing words spoken by that talker) and reading words (without imagery) on implicit and explicit tests. Subjects first performed a surface encoding task on spoken, imagined as spoken, or visually presented words, and then were given either an implicit test (perceptual identification or stem completion) or an explicit test (recognition or cued recall) involving auditorily presented words. Auditory presentation at study produced larger priming effects than did imaging or reading. Imaging and reading yielded priming effects of similar magnitude, whereas imaging produced lower performance than reading on the explicit test of cued recall. Voice changes between study and test weakened priming on the implicit tests, but did not affect performance on the explicit tests. Imagined voice changes affected priming only in the implicit task of stem completion. These findings show that the sensitivity of a memory test to perceptual information, either directly perceived or imagined, is an important dimension for dissociating incidental (implicit) and intentional (explicit) retrieval processes.