PubMed Health⌕ Search

Biomedical subjects

L J Trainor

Publications and source records attributed to L J Trainor.

17 recordsLinked to original sources
PubMed2001

Measuring temporal resolution in infants using mismatch negativity.

We show that the mismatch negativity (MMN) component of the event-related potential can be used to measure auditory temporal resolution in human infants. Infrequent stimuli with silent gaps of 4, 8, or 12 ms modulated the P2 component, generated MMN, and produced a P3a-like positivity. The data indicate that within-channel gap detection thresholds at 6 months are essentially at adult levels under conditions of little adaptation. Since MMN is elicited without attention and does not require a behavioural response, it can be measured similarly across the lifespan. We are now in a position to study the development of cross-channel temporal resolution and adaptation effects in infancy, and to examine how these abilities in infancy relate to later language acquisition.

Acoustic Stimulation↗
PubMed2000

Is infant-directed speech prosody a result of the vocal expression of emotion?

Many studies have found that infant-directed (ID) speech has higher pitch, has more exaggerated pitch contours, has a larger pitch range, has a slower tempo, and is more rhythmic than typical adult-directed (AD) speech. We show that the ID speech style reflects free vocal expression of emotion to infants, in comparison with more inhibited expression of emotion in typical AD speech. When AD speech does express emotion, the same acoustic features are used as in ID speech. We recorded ID and AD samples of speech expressing love-comfort, fear, and surprise. The emotions were equally discriminable in the ID and AD samples. Acoustic analyses showed few differences between the ID and AD samples, but robust differences across the emotions. We conclude that ID prosody itself is not special. What is special is the widespread expression of emotion to infants in comparison with the more inhibited expression of emotion in typical adult interactions.

Adult↗
PubMed2000

Infants' and adults' use of duration and intensity cues in the segmentation of tone patterns.

Adults and 8-month-olds were presented with sequences in which every third complex tone was either longer or more intense. Segmentation was measured by comparing the detection of silent gaps inserted into three possible locations in each pattern: Silent gaps inserted at perceived segmentation boundaries are harder to detect than gaps within perceived phrases or groups. A go/no-go conditioned head-turn (hand-raising for adults) procedure was used. In Experiment 1, detection was worse for the gaps following the longer complex tones than for the gaps at the other locations, suggesting that the longer tones marked the ends of perceived groups for both infants and adults. Experiment 2 showed that an increase in intensity did not result in any systematic grouping at either age.

Adult↗
PubMed1999

Using mismatch negativity to measure auditory temporal resolution thresholds.

It has been hypothesized that poor auditory temporal resolution is related to language-learning problems in children as well as problems with speech perception in noise in the elderly. We show that the presence of occasional silent gaps between short tone pips elicits mismatch negativity (MMN) in young adults. We also measured gap-detection thresholds with MMN that agree well with behavioural thresholds. Near threshold, the MMN increases as the gap size increases millisecond by millisecond. The MMN methodology for measuring temporal resolution is not only robust, but can be applied identically across the life span as it does not require the attention of participants or a behavioural response. We are now in a position to examine temporal resolution in infancy.

Acoustic Stimulation↗
PubMed1999

Distinctive messages in infant-directed lullabies and play songs.

Mothers were recorded singing a song of their choice in both a lullaby style and a play-song style to their 6-month-olds. Adult raters identified the play-song-style and lullaby-style versions with 100% accuracy. Play-song-style renditions were rated as being more brilliant, clipped, and rhythmic and as having more smiling and more prominent consonants. Lullaby-style renditions were characterized as being more airy, smooth, and soothing. Adults observed videotapes (without sound) of 6-month-olds listening to alternating lullaby-style and play-song-style trials and performed at above chance levels when determining which music the infants were hearing. Coding analyses revealed that infants focused their attention more toward themselves during lullaby-style trials and more toward the external world during play-song-style trials. These results suggest that singing may be used to regulate infants' states and to communicate emotional information.

Adolescent↗
PubMed1998

Mismatch negativity to speech stimuli in 8-month-old infants and adults.

The mismatch negativity (MMN) was measured in 15 normal awake 8-month-old infants and 10 adults to the speech consonants /da/ and /ta/. ERPs were analyzed at 11 electrodes (Fz, Cz, Pz, C3, C4, T3, T4, T5, T6, P3, P4). Four-hundred trials were presented: the /da/ standards with 80% probability and the /ta/ deviants with 20% probability. The ISI was 600 ms. An MMN was observed for both adults and infants but with different scalp distributions. A clear infant MMN was observed only at C3 and T3 electrodes, whereas the adult MMN was present at Fz, Cz, C3, C4 and Pz. A repeated-measures ANOVA on the normalized summed area between 200 and 250 ms revealed an age (adult vs. infant) x electrode interaction. Paired t-tests indicated that adults and infants showed significant differences at the C3, Cz, T3, Pz and T6 electrodes. The adult MMN was largest at Cz and C3 whereas the infant MMN was largest at T3. These data are discussed in terms of possible maturational changes in the MMN.

Adult↗
PubMed1997

Mothers' and fathers' singing to infants.

Mothers and fathers sang a song of their choice, once to their infant and once as if to their infant (simulated). The pitch of songs was higher and the tempo slower for infant-directed than for simulated versions. Listeners varying in child-care experience, musical background, and cultural origin reliably identified which of the two versions was infant-directed (Experiment 1). Identification accuracy was enhanced by musical training, knowledge of the singers' language and culture, and by greater pitch and tempo differences between versions. Other adult listeners who rated the singer's emotional engagement assigned significantly higher ratings to infant-directed than to simulated versions (Experiment 2). Differences in pitch and tempo between both versions predicted emotional engagement ratings. Finally, rating differences between infant-directed and simulated versions were highly correlated with identification accuracy.

Adolescent↗
PubMed1997

Effect of frequency ratio on infants' and adults' discrimination of simultaneous intervals.

Effects of frequency ratio simplicity on infants' and adults' processing of simultaneous pitch intervals with component sine wave tones were tested. Both infants and adults showed superior performance at detecting a change from a perfect 5th (2:3) to either a tritone (32:45) or a minor 6th (5:8) interval than at detecting the reverse discriminations (minor 6th or tritone to perfect 5th). Similarly, both infants and adults showed superior performance at detecting a change from an octave (1:2) to either a major 7th (8:15) or a minor 9th (15:32) interval than at detecting the reverse discriminations. In combination with previous findings of infants' superior discrimination of tone sequences with prominent perfect 5th intervals, these results suggest that both simultaneous and sequential intervals with simple ratios are easy to process early in development.

Adult↗
PubMed1996

Sensory consonance and the perceptual similarity of complex-tone harmonic intervals: tests of adult and infant listeners.

Two experiments examined the influence of sensory consonance on the perceptual similarity of simultaneous pairs of complex tones (harmonic intervals). In experiment 1, adults heard a sequence of five consonant intervals (each a perfect fifth, or 7 semitones) and judged whether a subsequently presented test interval was a member of the sequence. Discrimination performance was better when the test interval was dissonant (tritone, 6 semitones) rather than consonant (perfect fourth, 5 semitones), despite the fact that the change in interval width was twice as great for the consonant than for the dissonant comparison. In experiment 2, 7-month-old infants were tested with an operant headturn procedure in a similar design and exhibited an identical pattern of responding. Hence, for both age groups, consonance was more important than interval width in determining the perceived similarity of harmonic intervals.

Adult↗
PubMed1996

Effects of harmonics on relative pitch discrimination in a musical context.

The contribution of different harmonics to pitch salience in a musical context was examined by requiring subjects to discriminate a small (1/4 semitone) pitch change in one note of a melody that repeated in transposition. In Experiment 1, performance was superior when more harmonics were present (first five vs. fundamental alone) and when the second harmonic (of tones consisting of the first two harmonics) was in tune compared with when it was out of tune. In Experiment 2, the effects of harmonics 6 and 8, which stand in octave-equivalent simple ratios to the fundamental (2:3 and 1:2, respectively) were compared with harmonics 5 and 7, which stand in more complex ratios (4:5 and 4:7, respectively). When the harmonics fused into a single percept (tones consisting of harmonics 1, 2, and one of 5, 6, 7, or 8), performance was higher when harmonics 6 or 8 were present than when harmonics 5 or 7 were present. When the harmonics did not fuse into a single percept (tones consisting of the fundamental and one of 5, 6, 7, or 8), there was no effect of ratio simplicity.

Adult↗
PubMed1994

Key membership and implied harmony in Western tonal music: developmental perspectives.

We investigated the role of key membership and implied harmony in adults' and children's perception of tone sequences. Listeners were evaluated on their ability to detect three types of changes in one note of a well-structured Western tonal melody. In one change (out-of-key) the new note was not in the basis key, in another (out-of-harmony) it was in the key but not in the implied harmony, and in the third (within-harmony) it was in both the key and the implied harmony. Adults and 7-year-olds performed better on the out-of-key and out-of-harmony changes than on the within-harmony change, reflecting their implicit knowledge of key membership and implied harmony. Five-year-olds performed better on the out-of-key change than on the other two changes, reflecting the influence of key membership but not implied harmony. We consider the developmental precedence of key membership over implied harmony in the context of cross-cultural and theoretical perspectives.

Adolescent↗
PubMed1993

Musical context effects in infants and adults: key distance.

Adults and 9- to 11-month-old infants listened to repeated transpositions of either a prototypical Western melody that was based on the major triad or a nonprototypical Western melody that was based on the augmented triad. In both cases, the transpositions were either to related keys (standing in a 2:3 frequency ratio) or to unrelated keys (more complex frequency ratios). For the prototypical melody, both infants and adults more readily discriminated a change to the melody in the context of related keys. For the nonprototypical melody, infant listeners performed better in the context of related keys, but adult listeners performed worse. The findings indicate that the global context of auditory patterns influences the processing of pattern details for infant and adult listeners.

Acoustic Stimulation↗
PubMed1992

A comparison of infants' and adults' sensitivity to western musical structure.

Adults (n = 28) and 8-month-old infants (n = 48) listened to repeated transpositions of a 10-note melody exemplifying the rules of Western tonal music. They were tested for their detection of two types of changes to that melody: (a) a 4-semitone change in 1 note that remained within the key and implied dominant harmony (diatonic change) or (b) a 1-semitone change in the same note that went outside the key (nondiatonic change). Adults easily detected the nondiatonic change but had difficulty with the diatonic change. Infants detected both changes equally well, performing better than adults in some circumstances. These findings imply that there are qualitative differences in infants' and adults' processing of musical information.

Adult↗
PubMed1989

Aging and auditory temporal sequencing: ordering the elements of repeating tone patterns.

In a series of experiments, we examined age-related differences in adults' ability to order sequences of tones presented at various speeds and in contexts designed to promote or to impede stream segregation. In Experiment 1, 32 listeners (16 young, 16 old) were required to identify two repeating sequences that consisted of four tones (two from a high and two from a low frequency range) in different order. In Experiment 2, 32 listeners were required to judge whether the two recycled patterns from Experiment 1 were the same or different. In Experiment 3, four young and four old listeners were tested on the tasks of Experiment 2 over an extended period. In Experiment 4, 16 young and 16 old listeners were tested with sequences that were not recycled and were composed of tones drawn from a narrow frequency range. Elderly adults were less able than young adults to distinguish between tone sequences with contrasting order, regardless of the speed of presentation, the nature of the task (identification vs. same/different), the amount of practice, the frequency separation of the tones, or the presence or absence of recycling. These findings provide evidence of a temporal sequencing impairment in elderly listeners but reveal no indication of age differences in streaming processes.

Adolescent↗