The effect on language development of the special characteristics of speech addressed to children

Studies of adults' speech to children indicate that adults make a number of modifications in their speech when interacting with a young child and that some of these modifications may facilitate the child's language acquisition. Modified repetitions of the child's utterances, along with certain syntactic, semantic, and cognitive simplifications, appear to be potentially effective language-teaching devices. However, the special lexicon, phonological simplification, and higher pitch that also characterize this baby-talk style are much less likely to play important roles in the child's language learning. The child's role in affecting these modifications in adult speech is briefly discussed, and an optimal pattern of adult-child language interaction is suggested.     

Age differences in discrimination of simulated single-formant frequency transitions

We studied auditory discrimination of simulated single-formant frequency transitions that resembled portions of certain speech consonants. Significant age differences in transition discrimination occurred; both children and older adults required larger acoustic differences between transitions for discrimination than did teenagers/young adults. Longer transitions were more easily discriminated than shorter transitions by all listeners, and there were no differences between discriminations of rising and falling transitions. Teens/young adults and older adults, but not children, required larger frequency differences to discriminate frequency transitions followed by a steady-state sound than for transitions alone. There were also age differences in discrimination of steady-state sounds. These developmental-perceptual differences may help explain why children and older adults who have good pure-tone sensitivity may experience difficulty in understanding speech.     

Classifying color materials: children are less holistic than adults

Much recent research indicates that children respond to materials which are separable for adults as though those materials were integral. The present studies examined differences between 5-year-olds and adults in the processing of integral materials. In Study 1, both children and adults made a majority of similarity classifications for those materials. However, the children were found to make fewer of those integral similarity classifications and more dimensional classifications than adults for materials varying in the integral dimensions of chroma and value. In Study 2, children's similarity judgments were also indicative of greater separability of those dimensions. For both children and adults, similarity ratings given in Study 2 were predictive of classification behavior in Study 1. Age differences in similarity ratings were also predictive of age differences in classification. The overall pattern of results is consistent with the idea that children's perception is neither more nor less holistic than that of adults. Whether children or adults are found to be more holistic depends on the nature of the material presented. With integral materials, young children respond in a manner which appears less holistic than that of adults.     

The effects of the age of eyewitnesses on the accuracy and suggestibility of their testimony

Previous studies have compared the performance of young adult eyewitnesses with that of children or elderly eyewitnesses, but few studies have allowed direct comparison of the performance of all three age groups. The accuracy and suggestibility of accounts of a video recording of a kidnapping were investigated using an experimental eyewitness paradigm. Subjects were drawn from three age groups: children (aged 7–9 years); young adults (aged 16–18 years) and elderly subjects (aged 60–85 years). Subjects' accuracy in answering non-misleading questions and their susceptibility to misleading information was measured. Both the elderly and child subjects gave fewer correct answers and more incorrect answers to non-misleading questions than did young adults. The elderly subjects gave fewer correct responses but also fewer incorrect responses to non-misleading questions than did child subjects. Children were more suggestible than either elderly or young adults. No significant difference was found in the suggestibility of elderly and young adults. Contrary to the trace strength hypothesis no relationship was found between accuracy of recall and suggestibility. © 1997 John Wiley & Sons, Ltd.     

Dissociations in perceptual learning revealed by adult age differences in adaptation to time-compressed speech

When presented with several time-compressed sentences, young adults' performance improves with practice. Such adaptation has not been studied in older adults. To study age-related changes in perceptual learning, the authors tested young and older adults' ability to adapt to degraded speech. First, the authors showed that older adults, when equated for starting accuracy with young adults, adapted at a rate and magnitude comparable to young adults. However, unlike young adults, older adults failed to transfer this learning to a different speech rate and did not show additional benefit when practice exceeded 20 sentences. Listeners did not adapt to speech degraded by noise, indicating that adaptation to time-compressed speech was not attributable to task familiarity. Finally, both young and older adults adapted to spectrally shifted noise-vocoded speech. The authors conclude that initial perceptual learning is comparable in young and older adults but maintenance and transfer of this learning decline with age.     

The relationships between processing facial identity,emotional expression,facial speech,and gaze direction during development

Four experiments were conducted with 5- to 11-year-olds and adults to investigate whether facial identity, facial speech, emotional expression, and gaze direction are processed independently of or in interaction with one another. In a computer-based, speeded sorting task, participants sorted faces according to facial identity while disregarding facial speech, emotional expression, and gaze direction or, alternatively, according to facial speech, emotional expression, and gaze direction while disregarding facial identity. Reaction times showed that children and adults were able to direct their attention selectively to facial identity despite variations of other kinds of face information, but when sorting according to facial speech and emotional expression, they were unable to ignore facial identity. In contrast, gaze direction could be processed independently of facial identity in all age groups. Apart from shorter reaction times and fewer classification errors, no substantial change in processing facial information was found to be correlated with age. We conclude that adult-like face processing routes are employed from 5 years of age onward.     

Talking to children, foreigners, and retarded adults

Speech addressed to different categories of listeners was examined in a study in which undergraduate women taught a block design task to either a 6-year-old child, a retarded adult, a peer who spoke English as a second language (foreigner), or a peer who was an unimpaired native speaker of English. The speech addressed to children differed from the speech addressed to native adults along every major dimension that emerged in this study: It was clearer, simpler, and more attention maintaining, and it included longer pauses. Speech addressed to retarded adults was similar in numerous ways to the speech addressed to 6-year-olds; in some ways (e.g., repetitiveness), it was even more babyish. However, speech to the retarded adults did differ in timing from the other styles of speaking in that it included fewer and somewhat shorter pauses. Speech addressed to foreigners was more repetitive than speech addressed to native speakers, but in all other ways it was very similar. There was some evidence that speakers fine-tuned their communications to the level of cognitive and linguistic sophistication of their particular listener; for example, speakers addressing the more sophisticated foreigners (relative to those addressing the less sophisticated foreigners) used speech that included fewer devices for clarifying, simplifying, and maintaining the listeners' attention. We discuss the hypothesis that baby talk (the speech addressed to children) is a prototypical special speech register from which other special registers are derived.     

How scenes containing visual errors affect speech fluency in young and older adults

We compared young and older adults’ speech during an error detection task, with some pictures containing visual errors and anomalies and other pictures error-free. We analyzed three disfluency types: mid-phrase speech fillers (e.g., It’s a little, um, girl), repetitions (e.g., He’s trying to catch the- the birds), and repairs (e.g., She- you can see her legs). Older adults produced more mid-phrase fillers than young adults only when describing pictures containing errors. These often reflect word retrieval problems and represent clear disruptions to fluency, so this interaction indicates that the need to form and maintain representations of novel information can specifically compromise older adults’ speech fluency. Overall, older adults produced more repetitions and repairs than young adults, regardless of picture type, indicating general age-related increases in these disfluencies. The obtained patterns are discussed in the context of the Transmission Deficit Hypothesis and other approaches to age-related changes in speech fluency.     

Nonword repetition in children and adults: effects on movement coordination

Hearing and repeating novel phonetic sequences, or novel nonwords, is a task that taps many levels of processing, including auditory decoding, phonological processing, working memory, speech motor planning and execution. Investigations of nonword repetition abilities have been framed within models of psycholinguistic processing, while the motor aspects, which also are critical for task performance, have been largely ignored. We focused our investigation on both the behavioral and speech motor performance characteristics of this task as performed in a learning paradigm by 9‐ and 10‐year‐old children and young adults. Behavioral (percent correct productions) and kinematic (movement duration, lip aperture variability – an index of the consistency of inter‐articulator coordination on repeated trials) measures were obtained in order to investigate the short‐term (Day 1, first five vs. next five trials) and longer‐term (Day 1 vs. Day 2, first five vs. next five trials) changes associated with practice within and between sessions. Overall, as expected, young adults showed higher levels of behavioral accuracy and greater levels of coordinative consistency than the children. Both groups, however, showed a learning effect, such that in general, later Day 1 trials and Day 2 trials were shorter in duration and more consistent in coordination patterns than Day 1 early trials. Phonemic complexity of the nonwords had a profound effect on both the behavioral and speech motor aspects of performance. The children showed marked learning effects on all nonwords that they could produce accurately, while adults’ performance improved only when challenged by the more complex nonword stimuli in the set. The findings point to a critical role for speech motor processes within models of nonword repetition and suggest that young adults, similar to children, show short‐ and longer‐term improvements in coordinative consistency with repeated production of complex nonwords. There is also a clear developmental change in nonword production performance, such that less complex novel sequences elicit changes in speech motor performance in children, but not in adults.     

Inner speech slips exhibit lexical bias, but not the phonemic similarity effect

Inner speech, that little voice that people often hear inside their heads while thinking, is a form of mental imagery. The properties of inner speech errors can be used to investigate the nature of inner speech, just as overt slips are informative about overt speech production. Overt slips tend to create words (lexical bias) and involve similar exchanging phonemes (phonemic similarity effect). We examined these effects in inner and overt speech via a tongue-twister recitation task. While lexical bias was present in both inner and overt speech errors, the phonemic similarity effect was evident only for overt errors, producing a significant overtness by similarity interaction. We propose that inner speech is impoverished at lower (featural) levels, but robust at higher (phonemic) levels.     

Auditory habituation in young and older adults: the verbal transformation effect

In 3 experiments, auditory massed repetition was used to examine age-related differences in habituation by means of the verbal transformation paradigm. Participants heard 10 words (5 high frequency and 5 low frequency), each presented 180 times, and they reported perceived changes in the repeated words (verbal transformations). In these experiments, older adults reported fewer illusory percepts than young adults. Older adults' loss of auditory acuity and slowing of processing, stimulus degradation (in young adults), and instructions biasing the report of these illusory percepts did not account for the fewer illusory percepts reported by the older adults. These findings suggest that older adults' reduced susceptibility to habituation arises from centrally located declines in the transmission of information within the word-recognition pathway. The discussion focuses on the implications that these age-related declines may have on word identification during on-line speech perception.     

Converting between word and syllable counts in children's conversational speech samples

Several authors have suggested that it is possible to convert between word and syllable counts for basic clinical measurements such as the frequency of speech disfluencies or speaking rate in conversational speech samples. Based primarily on results from adults' speech samples, proposed conversion factors have averaged approximately 1.5 syllables per word. Because children produce fewer multisyllabic words than adults, this conversion factor is probably not appropriate for children's speech samples. This study sought to develop a more accurate conversion factor for children's speech by comparing syllable and word counts in spontaneous speech samples produced by 50 children, age 3 to 5. Analyses revealed an average ratio of 1.15 syllables per word, which was consistent across different subjects, across subject groups (children who stutter and children who do not stutter) and also, somewhat surprisingly, across age groups (3-year olds, 4-year olds, and 5-year olds). Results suggest that this constant conversion factor of 1.15 can be used to convert between word and syllable with sufficient precision to allow clinicians to compare their data to published guidelines and benchmarks about childhood stuttering.     

Different Effects of Dual Task Demands on the Speech of Young and Older Adults

Abstract

Young and older adults provided language samples in response to elicitation questions while concurrently performing 3 different tasks. The language samples were scored on three dimensions: fluency, grammatical complexity, and content. Previous research has shown that older adults use a restricted speech register that is grammatically less complex than young adults’ and has suggested that this restricted speech register is buffered from the costs of dual task demands. This hypothesis was tested by comparing language samples collected during a baseline condition with those produced while the participants were performing the concurrent tasks. The results indicate that young and older adults adopt different strategies when confronted with dual task demands. Young adults shift to a restricted speech register when confronted with dual task demands. Older adults, who were already using a restricted speech register, became less fluent although the grammatical complexity and informational content of their speech was preserved. Hence, some but not all aspects of older adults’ speech are buffered from dual task demands.     

Effects of diurnal variation on the Test of Variables of Attention performance in young adults with attention-deficit/hyperactivity disorder

The Test of Variables of Attention (TOVA) is a continuous performance test that assesses attention, impulsivity, and processing speed. Continuous performance tests are used in the assessment of attention-deficit/hyperactivity disorder (ADHD) in children and adults. TOVA norms are based on a morning administration, and any TOVA administered after 1:00 p.m. is flagged as potentially invalid. Whereas the testing time recommendations make sense for pediatric samples, it is unclear whether they are appropriate for young adults, who typically show significant phase delay in their diurnal rhythms. The current study explores the impact of time of day on TOVA performance in young adults with ADHD. Participants were randomly assigned to either morning or afternoon administration. We found no significant diurnal variation in TOVA performance. We also found no interaction between diurnal preference and time of day of administration. Night owls endorsed more inattention symptoms on a self-report measure than more intermediate individuals but actually made significantly fewer omission (inattention) errors on the TOVA. Self-reported symptoms of inattention showed moderate, significant correlations with various TOVA performance indices. Self-reported symptoms of hyperactivity and impulsivity, however, showed no relationship to TOVA performance. These results suggest that the TOVA can be administered to adults with ADHD outside of the hours recommended in the manual without significantly compromising the interpretative validity of test score interpretation. Thus, a TOVA report that is consistent with ADHD should not be dismissed simply because it was administered in the late afternoon.     

Phonological considerations in children's early imitative and spontaneous speech

The relationship between the phonological characteristics of young children's unsolicited imitative and spontaneous speech was examined as a function of (1) the level of the children's linguistics development, and (2) the children's knowledge of the words imitated. A greater number of phonological discrepancies were seen in children with lexicons of fewer than 40 words than in children with larger lexical repertories. Such discrepancies were also more likely when the children displayed little comprehension of the words they were imitating. This tendency was particularly strong in the children with limited lexicons. The results are discussed in terms of a developmental shift in the bases of children's phonological organization.     

Phonemic awareness and spelling: children's judgments do not always agree with adults

The ability to make explicit judgments about speech sounds is important in learning to read and write an alphabetic system. However, even when children can make consistent judgments about sounds their judgments do not always agree with those of adults. In this study, some children from groups of kindergartners (mean age 5 years, 10 months) and first graders (mean age 6, 7) stated that /tr/ (as in "truck") did not begin with the sound /t/. This judgment was reflected in these children's spellings: They tended to spell /t/ before /r/ with CH, reflecting its affrication. Parallel results were found for /dr/. Further, some children judged that /c/ (as in "chill") and /j/ (as in "Jill") began with /t/ and /d/, respectively. They used the letters T and D to spell these sounds. Thus, children's attention to a phonetic level may result in judgments of speech sounds and spellings that are different from those of adults.     

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.