Effects of aging and musical experience on the representation of tonal hierarchies

Listeners perceive complex pitch-temporal structure in melodies

In typical Western music, important pitches occur disproportionately often on important beats, referred to as the tonal-metric hierarchy (Prince & Schmuckler, 2014, Music Perception, 31, 254-270). We tested whether listeners are sensitive to this alignment of pitch and temporal structure. In Experiment 1, the stimuli were 200 artificial melodies with random pitch contours; all melodies had both a regular beat and a pitch class distribution that favored one musical key, but had either high or low agreement with the tonal-metric hierarchy. Thirty-two listeners rated the goodness of each melody, and another 41 listeners rated the melodies' metric clarity (how clear the beat was). The tonal-metric hierarchy did not affect either rating type, likely because the melodies may have only weakly (at best) established a musical key. In Experiment 2, we shuffled the pitches in 60 composed melodies (scrambling pitch contour, but not rhythm) to generate versions with high and low agreement with the tonal-metric hierarchy. Both ratings of goodness (N = 40) and metric clarity (N = 40) revealed strong evidence of the tonal-metric hierarchy influencing ratings; there was no effect of musical training. In Experiment 3, we phase-shifted, rather than shuffled, the pitches from the composed melodies, thus preserving pitch contour. Both rating types (goodness N = 43, metric clarity N = 32) replicated the results of Experiment 2. These findings establish the psychological reality of the tonal-metric hierarchy.

Neurophysiological and Behavioral Differences between Older and Younger Adults When Processing Violations of Tonal Structure in Music

Aging is associated with decline in both cognitive and auditory abilities. However, evidence suggests that music perception is relatively spared, despite relying on auditory and cognitive abilities that tend to decline with age. It is therefore likely that older adults engage compensatory mechanisms which should be evident in the underlying functional neurophysiology related to processing music. In other words, the perception of musical structure would be similar or enhanced in older compared to younger adults, while the underlying functional neurophysiology would be different. The present study aimed to compare the electrophysiological brain responses of younger and older adults to melodic incongruities during a passive and active listening task. Older and younger adults had a similar ability to detect an out-of-tune incongruity (i.e., non-chromatic), while the amplitudes of the ERAN and P600 were reduced in older adults compared to younger adults. On the other hand, out-of-key incongruities (i.e., non-diatonic), were better detected by older adults compared to younger adults, while the ERAN and P600 were comparable between the two age groups. This pattern of results indicates that perception of tonal structure is preserved in older adults, despite age-related neurophysiological changes in how melodic violations are processed.

Age-related difference in melodic pitch perception is probably mediated by temporal processing: empirical and computational evidence

OBJECTIVE

This study was designed to examine whether age-related differences in melodic pitch perception may be mediated by temporal processing. Temporal models of pitch suggest that performance will decline as the lowest component of a complex tone increases in frequency, regardless of age. In addition, if there are age-related deficits in temporal processing in older adults, this group may have reduced performance relative to younger adults even in the most favorable conditions.

DESIGN

Six younger adults and 10 older adults with clinically normal audiograms up to 8 kHz were tested in a melodic pitch perception task. In each trial, two consecutive four-note melodies were presented to the listener. Melodies were identical with the exception of one note in the second melody that was shifted in pitch. The listener was required to identify which note was shifted. All notes consisted of eight successive harmonic components, with the average lowest component manipulated to be the 4th, 8th, or 12th component of the harmonic series, with lower components being absent.

RESULTS

Age-related differences in melodic pitch perception were only apparent when stimulus parameters favored temporal processing of pitch. Furthermore, modeling a loss of periodicity coding yielded an outcome consistent with the observed behavioral results. Although younger adults generally outperformed older adults, about one-quarter of the older adults performed at levels that were equivalent to those of younger adults. The only follow-up tests that were able to differentiate these exceptional older adults were tests that would be sensitive to temporal processing: fundamental frequency difference limens and 500 Hz pure-tone difference limens. In contrast, otoacoustic emissions and high-frequency pure-tone thresholds, which are more commonly associated with spectral processing deficits, were not able to differentiate older exceptional adults from older typical adults.

CONCLUSION

Age-related declines in temporal processing contribute to deficits in melodic pitch perception. However, some exceptional older adults with normal audiograms preserve excellent temporal processing and continue to perform at levels that are typical of younger adults.

The relation between instrumental musical activity and cognitive aging

OBJECTIVE

Intensive repetitive musical practice can lead to bilateral cortical reorganization. However, whether musical sensorimotor and cognitive abilities transfer to nonmusical cognitive abilities that are maintained throughout the life span is unclear. In an attempt to identify modifiable lifestyle factors that may potentially enhance successful aging, we evaluated the association between musical instrumental participation and cognitive aging.

METHOD

Seventy older healthy adults (ages 60-83) varying in musical activity completed a comprehensive neuropsychological battery. The groups (nonmusicians, low and high activity musicians) were matched on age, education, history of physical exercise, while musicians were matched on age of instrumental acquisition and formal years of musical training. Musicians were classified in the low (1-9 years) or high (>10 years) activity group based on years of musical experience throughout their life span.

RESULTS

The results of this preliminary study revealed that participants with at least 10 years of musical experience (high activity musicians) had better performance in nonverbal memory (η2 = .106), naming (η2 = .103), and executive processes (η2 = .131) in advanced age relative to nonmusicians. Several regression analyses evaluated how years of musical activity, age of acquisition, type of musical training, and other variables predicted cognitive performance.

CONCLUSIONS

These correlational results suggest a strong predictive effect of high musical activity throughout the life span on preserved cognitive functioning in advanced age. A discussion of how musical participation may enhance cognitive aging is provided along with other alternative explanations.

Musicians' and nonmusicians' short-term memory for verbal and musical sequences: comparing phonological similarity and pitch proximity

Language-music comparative studies have highlighted the potential for shared resources or neural overlap in auditory short-term memory. However, there is a lack of behavioral methodologies for comparing verbal and musical serial recall. We developed a visual grid response that allowed both musicians and nonmusicians to perform serial recall of letter and tone sequences. The new method was used to compare the phonological similarity effect with the impact of an operationalized musical equivalent-pitch proximity. Over the course of three experiments, we found that short-term memory for tones had several similarities to verbal memory, including limited capacity and a significant effect of pitch proximity in nonmusicians. Despite being vulnerable to phonological similarity when recalling letters, however, musicians showed no effect of pitch proximity, a result that we suggest might reflect strategy differences. Overall, the findings support a limited degree of correspondence in the way that verbal and musical sounds are processed in auditory short-term memory.

Episodic Encoding in Normal Aging: Attentional Resources Hypothesis Extended to Musical Material

The goal of the present study was to examine age-related changes in musical episodic memory for novel tunes. This was conducted by manipulating the encoding condition in a recognition paradigm. After receiving memory instructions (intentional condition), older and younger participants obtained equivalent hits. In contrast, when intentional encoding was accompanied by a dancing judgment (dancing + intentional condition), the recognition performance of the older persons was severely impaired. Impaired recognition was also found when participants only judged the excerpts without being instructed to memorize them (dancing judgment condition). Although older participants demonstrated a preserved ability to perform the dancing judgment on its own, this ability was not optimal and likely precluded the initiation of more elaborate encoding strategies. These results suggest that asking older persons to divide their attention in the study phase reduces the quality of their musical encoding. Given this extension to musical material, we discuss the notion that the age-related attentional resource decline appears to be domain-general rather than specific to verbal material.

Acuity of auditory images in pitch and time

We examined the pitch and temporal acuity of auditory expectations/images formed under attentional-cuing and imagery task conditions, in order to address whether auditory expectations and auditory images are functionally equivalent. Across three experiments, we observed that pitch acuity was comparable between the two task conditions, whereas temporal acuity deteriorated in the imagery task. A fourth experiment indicated that the observed pitch acuity could not be attributed to implicit influences of the primed context alone. Across the experiments, image acuity in both pitch and time was better in listeners with more musical training. The results support a view that auditory images are multifaceted and that their acuity along any given dimension depends partially on the context in which they are formed.

Quantifying complex patterns of bioacoustic variation: use of a neural network to compare killer whale (Orcinus orca) dialects

A quantitative measure of acoustic similarity is crucial to any study comparing vocalizations of different species, social groups, or individuals. The goal of this study was to develop a method of extracting frequency contours from recordings of pulsed vocalizations and to test a nonlinear index of acoustic similarity based on the error of an artificial neural network at classifying them. Since the performance of neural networks depends on the amount of consistent variation in the training data, this technique can be used to assess such variation from samples of acoustic signals. The frequency contour extraction and the neural network index were tested on samples of one call type shared by nine social groups of killer whales. For comparison, call similarity was judged by three human subjects in pairwise classification tasks. The results showed a significant correlation between the neural network index and the similarity ratings by the subjects. Both measures of acoustic similarity were significantly correlated with the groups' association patterns, indicating that both methods of quantifying acoustic similarity are biologically meaningful. An index based on neural network analysis therefore represents an objective and repeatable means of measuring acoustic similarity, and allows comparison of results across studies, species and time.