Earwitnesses: effects of speech duration,retention interval and acoustic environment

An experiment was conducted to investigate the reliability of voice lineups. More specifically, the experiment was designed to look into the effects of retention interval (an immediate test or after a week), speech duration (30 or 70 s) and acoustic environment (indoors or indoors and outdoors) on speaker identification accuracy. In addition, the relation between confidence assessments of both participants and test assistant on the one hand and identification accuracy was explored. A total of 361 participants heard the target voice in one of four exposure conditions (short or long text and speech samples recorded only indoors or indoors and outdoors). Half the participants were tested immediately after exposure to the target voice and half 1 week later. The results show that the target was correctly identified in 42% of cases. In the target‐absent condition there were 51% false alarms. Acoustic environment did not affect identification accuracy. There was an interaction between speech duration and retention interval in the target‐absent condition. When listeners were tested after a week, they made fewer false identifications if the speech sample was long. No effects were found when participants were tested immediately. Only the confidence scores of the test assistant had predictive value. Taking the confidence score of the test assistant into account therefore increases the diagnostic value of the identity parade. Copyright © 2004 John Wiley & Sons, Ltd.     

A language effect in voice identification

Bilingual students recorded messages in English, Spanish, and English with a strong Spanish accent. Monolingual English-speaking subjects heard a single message and attempted to identify the voice in a six-person line-up 1 week later. The line-up message was delivered in the same language and accent as the initial message. Voices were identified best when speaking English and worst when speaking Spanish. Identification accuracy was intermediate for the accent condition. There were no reliable differences among conditions in false alarms when the target voice was absent from the line-up. The effect of language was replicated using a 30-min retention interval. Familiarity with the language and language constraints on voice characteristics were discussed as possible explanations of the language effect.     

Earwitness identification performance: the effect of language,target, deliberate strategies and indirect measures

The present study examined whether voice identification performance is influenced by language comprehension (i.e. familiar vs. non‐familiar language) and target presence (target‐present (TP) vs. target‐absent line‐ups (TA)). It also looked at the relationship of deliberate strategies and indirect measures (i.e. confidence, difficulty and pressure) with performance. Sixty Native English speakers were exposed to an auditory event involving 45 to 50 seconds of speech. After 30 minutes delay, participants listened to a voice line‐up (TP or TA) in either a familiar (i.e. English) or unfamiliar language (i.e. French) according to the language spoken during the event, and were then asked to identify the original speaker's voice. Participants demonstrated significantly better performance for the familiar language/TP line‐ups. Participants who reported using the ‘elimination’ strategy were significantly more accurate than participants who reported using either a ‘matching’ strategy or no strategy. Indirect measures were not found to be good predictors of performance, except for confidence regarding TA accuracy. Copyright © 2006 John Wiley & Sons, Ltd.     

Relative Difficulty of Understanding Foreign Accents as a Marker of Proficiency

Foreign‐accented speech is generally harder to understand than native‐accented speech. This difficulty is reduced for non‐native listeners who share their first language with the non‐native speaker. It is currently unclear, however, how non‐native listeners deal with foreign‐accented speech produced by speakers of a different language. We show that the process of (second) language acquisition is associated with an increase in the relative difficulty of processing foreign‐accented speech. Therefore, experiencing greater relative difficulty with foreign‐accented speech compared with native speech is a marker of language proficiency. These results contribute to our understanding of how phonological categories are acquired during second language learning.     

Accent modulates access to word meaning: Evidence for a speaker-model account of spoken word recognition

Speech carries accent information relevant to determining the speaker’s linguistic and social background. A series of web-based experiments demonstrate that accent cues can modulate access to word meaning. In Experiments 1–3, British participants were more likely to retrieve the American dominant meaning (e.g., hat meaning of “bonnet”) in a word association task if they heard the words in an American than a British accent. In addition, results from a speeded semantic decision task (Experiment 4) and sentence comprehension task (Experiment 5) confirm that accent modulates on-line meaning retrieval such that comprehension of ambiguous words is easier when the relevant word meaning is dominant in the speaker’s dialect. Critically, neutral-accent speech items, created by morphing British- and American-accented recordings, were interpreted in a similar way to accented words when embedded in a context of accented words (Experiment 2). This finding indicates that listeners do not use accent to guide meaning retrieval on a word-by-word basis; instead they use accent information to determine the dialectic identity of a speaker and then use their experience of that dialect to guide meaning access for all words spoken by that person. These results motivate a speaker-model account of spoken word recognition in which comprehenders determine key characteristics of their interlocutor and use this knowledge to guide word meaning access.     

Accommodating variability in voice and foreign accent: flexibility of early word representations

In six experiments with English‐learning infants, we examined the effects of variability in voice and foreign accent on word recognition. We found that 9‐month‐old infants successfully recognized words when two native English talkers with dissimilar voices produced test and familiarization items ( Experiment 1 ). When the domain of variability was shifted to include variability in voice as well as in accent, 13‐, but not 9‐month‐olds, recognized a word produced across talkers when only one had a Spanish accent ( Experiments 2 and 3 ). Nine‐month‐olds accommodated some variability in accent by recognizing words when the same Spanish‐accented talker produced familiarization and test items ( Experiment 4 ). However, 13‐, but not 9‐month‐olds, could do so when test and familiarization items were produced by two distinct Spanish‐accented talkers ( Experiments 5 and 6 ). These findings suggest that, although monolingual 9‐month‐olds have abstract phonological representations, these representations may not be flexible enough to accommodate the modifications found in foreign‐accented speech.     

Foreign accent strength and listener familiarity with an accent codetermine speed of perceptual adaptation

We investigated how the strength of a foreign accent and varying types of experience with foreign-accented speech influence the recognition of accented words. In Experiment 1, native Dutch listeners with limited or extensive prior experience with German-accented Dutch completed a cross-modal priming experiment with strongly, medium, and weakly accented words. Participants with limited experience were primed by the medium and weakly accented words, but not by the strongly accented words. Participants with extensive experience were primed by all accent types. In Experiments 2 and 3, Dutch listeners with limited experience listened to a short story before doing the cross-modal priming task. In Experiment 2, the story was spoken by the priming task speaker and either contained strongly accented words or did not. Strongly accented exposure led to immediate priming by novel strongly accented words, while exposure to the speaker without strongly accented tokens led to priming only in the experiment’s second half. In Experiment 3, listeners listened to the story with strongly accented words spoken by a different German-accented speaker. Listeners were primed by the strongly accented words, but again only in the experiment’s second half. Together, these results show that adaptation to foreign-accented speech is rapid but depends on accent strength and on listener familiarity with those strongly accented words.     

Imitation improves language comprehension

Humans imitate each other during social interaction. This imitative behavior streamlines social interaction and aids in learning to replicate actions. However, the effect of imitation on action comprehension is unclear. This study investigated whether vocal imitation of an unfamiliar accent improved spoken-language comprehension. Following a pretraining accent comprehension test, participants were assigned to one of six groups. The baseline group received no training, but participants in the other five groups listened to accented sentences, listened to and repeated accented sentences in their own accent, listened to and transcribed accented sentences, listened to and imitated accented sentences, or listened to and imitated accented sentences without being able to hear their own vocalizations. Posttraining measures showed that accent comprehension was most improved for participants who imitated the speaker's accent. These results show that imitation may aid in streamlining interaction by improving spoken-language comprehension under adverse listening conditions.     

The effects of post ‐identification feedback and age on retrospective eyewitness memory

Two studies examined the effects of post‐identification feedback, age, and retention interval on participants' memories and beliefs about memories for a videotaped event, as captured by a store surveillance camera. After viewing the video, they were then asked to identify the suspect from a target‐absent photo line‐up. After making their identification, some participants were given information suggesting that their identification was correct, while others were given no information about the accuracy of their identification. In both experiments participants who received confirming feedback indicated they were more confident in their identification, paid more attention to the video, and that they were more willing to testify in court than those who received no feedback. The confidence inflation effects of post‐identification feedback did not vary with retention interval or age. These results are consistent with a position focusing on accessibility, which suggests that witnesses have little or no retrievable recollection of how sure they were at the time of their identification. Copyright © 2005 John Wiley & Sons, Ltd.     

Identification accuracy for single‐ and double‐perpetrator crimes: Does accomplice gender matter?

There is an important mismatch between empirical research on the accuracy of eyewitness identification and the real world of criminal investigation. Most research models single‐perpetrator crimes, but in the real world, most crimes involve multiple perpetrators. This study examined how the number of perpetrators affects eyewitness identification by manipulating the gender of accomplices. Observers viewed a video of a staged crime. The crime was committed by a male or female perpetrator, who was presented alone or with an accomplice of the same or the opposite gender. The observers were then asked to identify the perpetrators from target‐present or target‐absent line‐ups. The results revealed a double‐perpetrator disadvantage, which was manifested in reduced identification accuracy on target‐present line‐ups. Importantly, however, the gender of the perpetrator or the accomplice had no effect on this disadvantage. This double‐perpetrator disadvantage is attributed to the need to divide attention between two concurrent people, compared to single‐culprit crimes, rather than an impairment of visual encoding processes. The implications of these findings are discussed.     

The Mystery Man Can Help Reduce False Identification for Child Witnesses: Evidence from Video Line‐ups

It is well established that children (as young as 5 years) can correctly identify a target from a target present (TP) line‐up as accurately as adults; however, when shown a target absent (TA) line‐up, children make more false identifications. In the present study, children aged 5–7 and 8–11 years viewed a film of a staged theft, then 1–2 days later were shown either a TP or TA video line‐up. Half of the witnesses viewed line‐ups that included a ‘mystery man’ (a black silhouette with a white question mark), which they could select if they did not recognise anyone from the line‐up. When the ‘mystery man’ was present in the line‐up, there were significantly fewer false identifications for the TA line‐ups. This study shows that including a silhouette in a video line‐up can help reduce false identifications for children as young as 5 years of age, without reducing correct identifications. Copyright © 2012 John Wiley & Sons, Ltd.     

Uniforms affect the accuracy of children's eyewitness identification decisions

A substantial proportion of line‐up identifications involving child eyewitnesses in the UK are conducted by police officers wearing uniform. This study examined the possibility that wearing a uniform constitutes an authority cue that adversely affects a child's ability to make accurate eyewitness identifications. Sixty participants aged 9–10 years old witnessed a staged crime and were later asked to identify a ‘burglar’ from a simultaneous line‐up using a 2 (uniform: present vs. absent) × 2 (target: present vs. absent) design. Children in the uniform present conditions made significantly more choices than children in the uniform absent conditions. More importantly, in the presence of a uniform, children made significantly more false identifications in target‐absent line‐ups. Analysis of supplementary, identification‐related variables (identification time and confidence, state anxiety) suggested that (1) the children experienced uncertainty if the target was absent from the line‐up, but (2) this uncertainty was not expressed when the line‐up administrator wore a uniform, leading to an increase in false identifications. Implications for line‐up administration procedures for children are discussed. Copyright © 2009 John Wiley & Sons, Ltd.     

Perspective Taking as a Means of Reducing Negative Stereotyping of Individuals Who Speak English as a Second Language1

As a test of the hypothesis that perspective taking reduces stereotyping of individuals who speak English as a second language, 160 college students participated in a 2 × 2 factorial experiment. Participants heard an audio recording of either a native or non‐native speaker of English. Then, they wrote a paragraph about the speaker either with instructions to take the speaker's perspective or with no perspective‐taking instructions. Finally, they rated the speaker on characteristics related to ability and accomplishment. Overall, the participants rated the native speaker of English more highly than the non‐native speaker. However, supporting the hypothesis, participants instructed to take the perspective of the non‐native speaker rated her more highly than did participants not instructed to take her perspective.     

Live Showups and Their Influence on a Subsequent Video Line‐up

A live showup (known as a street identification in the UK) allows the perpetrator to be identified shortly after a street crime. If the suspect disputes the identification, a video line‐up often ensues. Four experiments examined the reliability of live showups and their influence on a subsequent video line‐up using realistic procedures and conditions. Similar proportions of culprits and innocent suspects were identified from live showups and video line‐ups. Both culprits and innocent suspects previously identified were likely to be identified again in a subsequent line‐up, with delays from a few minutes to a month. Only a weak effect of clothing bias was observed. There was strong evidence of commitment to a previous identification but no reliable evidence of source monitoring errors. The results suggest that a live showup is not less fair than a line‐up, but the use of repeated identification procedures introduces an unfair bias against innocent suspects. Copyright © 2011 John Wiley & Sons, Ltd.     

Accent trumps race in guiding children's social preferences

A series of experiments investigated the effect of speakers' language, accent, and race on children's social preferences. When presented with photographs and voice recordings of novel children, 5-year-old children chose to be friends with native speakers of their native language rather than foreign-language or foreign-accented speakers. These preferences were not exclusively due to the intelligibility of the speech, as children found the accented speech to be comprehensible, and did not make social distinctions between foreign-accented and foreign-language speakers. Finally, children chose same-race children as friends when the target children were silent, but they chose other-race children with a native accent when accent was pitted against race. A control experiment provided evidence that children's privileging of accent over race was not due to the relative familiarity of each dimension. The results, discussed in an evolutionary framework, suggest that children preferentially evaluate others along dimensions that distinguished social groups in prehistoric human societies.     

The Positive Influence of Creating a Holistic Facial Composite on Video Line‐up Identification

Witnesses to a crime may be asked to create a facial composite of the offender from memory. They may then view a suspect in a police line‐up. Previous research on this topic has found both recognition impairment and enhancement following composite construction. In Experiment 1, creator‐participants employed the holistic facial composite system system EFIT‐V or the feature‐based E‐FIT system to create a single composite, and in Experiment 2, creators constructed up to three EFIT‐Vs. In both experiments, facial composite creators were one‐and‐a‐half times more likely than non‐composite creating controls to make correct target identifications from a video line‐up. No between condition effects were found in target‐absent trials in Experiment 1. The development of holistic facial composite systems has enhanced suspect identification rates in police investigations, and these results suggest that the use of such a system can also have a positive influence on a composite‐creating witness' later recognition of the suspect. Copyright © 2014 John Wiley & Sons, Ltd.     

When repeating aloud enhances episodic memory for spoken words: interactions between production- and perception-derived variability

We demonstrate that the phonetic detail of an original speaker’s pronunciation for a word can be detected with a memory measure even when a participant listens to and then repeats that word aloud (production). At study, native English participants heard English words pronounced by a native speaker of American-English or by a Chinese national. For half of the words they listened. For the others, they produced it. In both recall and old/new recognition tests in Experiment 1, production improved performance relative to listening alone. Effects of accent were present only in recognition and only in interaction with production. In Experiment 2, a source-monitoring recognition test where participants identified whether the speaker of a word changed from study to test, effects of accent and production were additive indicating that hearing an unfamiliar accent increased memory irrespective of production. An exemplar account including both production- as well as perception-derived experience describes the outcome.     

How many voices did you hear? Natural variability disrupts identity perception from unfamiliar voices

Our voices sound different depending on the context (laughing vs. talking to a child vs. giving a speech), making within‐person variability an inherent feature of human voices. When perceiving speaker identities, listeners therefore need to not only ‘tell people apart’ (perceiving exemplars from two different speakers as separate identities) but also ‘tell people together’ (perceiving different exemplars from the same speaker as a single identity). In the current study, we investigated how such natural within‐person variability affects voice identity perception. Using voices from a popular TV show, listeners, who were either familiar or unfamiliar with this show, sorted naturally varying voice clips from two speakers into clusters to represent perceived identities. Across three independent participant samples, unfamiliar listeners perceived more identities than familiar listeners and frequently mistook exemplars from the same speaker to be different identities. These findings point towards a selective failure in ‘telling people together’. Our study highlights within‐person variability as a key feature of voices that has striking effects on (unfamiliar) voice identity perception. Our findings not only open up a new line of enquiry in the field of voice perception but also call for a re‐evaluation of theoretical models to account for natural variability during identity perception.     

A meta‐analysis of the effects of speakers' accents on interpersonal evaluations

This paper reports a meta‐analysis of the empirical literature on the effects of speakers' accents on interpersonal evaluations. Our review of the published literature uncovered 20 studies that have compared the effects of standard accents (i.e., the accepted accent of the majority population) versus non‐standard accents (i.e., accents that are considered foreign or spoken by minorities) on evaluations about the speakers. These 20 studies yielded 116 independent effect sizes on an array of characteristics that were selected by the original researchers. We classified each of the characteristics as belonging to one of three domains that have been traditionally discussed in this area, namely status (e.g., intelligence, social class), solidarity (trustworthiness, in‐group–out‐group member), and dynamism (level of activity and liveliness). The effect was particularly strong when American Network accented speakers were compared with non–standard‐accented speakers. These results underscore prior research showing that speakers' accents have powerful effects on how others perceive them. These and other results are discussed in the context of the literature along with implications for future research in this area. Copyright © 2011 John Wiley & Sons, Ltd.     

Evaluations of Employment Suitability: Does Accent Always Matter?

This “matched‐guise” study provides data regarding attitudes toward (Mandarin) Chinese speakers by eliciting non‐Asian Americans' reactions to Chinese speaker using 2 varieties of English (standard American and Mandarin Chinese‐accented) and introduced in the context of an employment interview with either an Anglo‐American or ethnic Chinese name. Results indicate that speakers in all conditions were rated equally suitable for 3 types of employment. Despite the fact that language attitudes research has consistently demonstrated that individuals with nonstandard accents are judged to be less suitable for high‐status jobs and more suitable for low‐status jobs, the present results contradict this generalization.