Effects of aging on processing of novel musical structure

Age and familiarity effects on musical memory

BACKGROUND

A common complaint in older adults is trouble with their memory, especially for new information. Current knowledge about normal aging and changes in memory identify a divide between memory tasks that are unaffected by aging and those that are. Among the unaffected are recognition tasks. These memory tasks rely on accessing well-known information, often include environmental support, and tend to be automatic. Negative age effects on memory are often observed at both encoding and during recall. Older adults often have difficulty with recall tasks, particularly those that require effortful self-initiated processing, episodic memory, and retention of information about contextual cues. Research in memory for music in healthy aging suggests a skill-invariance hypothesis: that age effects dominate when general-purpose cognitive mechanisms are needed to perform the musical task at hand, while experience effects dominate when music-specific knowledge is needed to perform the task [1].

AIMS

The goals of this pair of studies were to investigate the effects of age and familiarity on musical memory in the context of real pieces of music, and to compare a live concert experimental setting with a lab-based experimental setting.

METHOD

Participants' task was to click a button (or press the spacebar) when they heard the target theme in three pieces of music. One was Mozart's Eine Kleine Nachtmusik and the others were original pieces commissioned for this study, one tonal and one atonal. Participants heard the relevant theme three times before listening to a piece of music. The music was performed by the Newfoundland Symphony Orchestra; participants either attended the concert, or watched a recording of the concert in the lab. Participants also completed two short cognitive tests and filled out a questionnaire collecting demographic information and a hearing abilities self-assessment.

RESULTS

We find a significant effect of familiarity and setting but not of age or musical training on recognition performance as measured by d'. More specifically, performance is best for the familiar, tonal piece, moderate for the unfamiliar tonal piece and worst for the unfamiliar atonal piece. Performance was better in the live setting than the lab setting.

CONCLUSIONS

The absence of an age effect provides encouraging evidence that music's diverse cues may encourage cognitive scaffolding, in turn improving encoding and subsequent recognition. Better performance in an ecological versus lab setting supports the expansion of ecological studies in the field.

Large-Scale Analysis of Auditory Segregation Behavior Crowdsourced via a Smartphone App

The human auditory system is adept at detecting sound sources of interest from a complex mixture of several other simultaneous sounds. The ability to selectively attend to the speech of one speaker whilst ignoring other speakers and background noise is of vital biological significance—the capacity to make sense of complex ‘auditory scenes’ is significantly impaired in aging populations as well as those with hearing loss. We investigated this problem by designing a synthetic signal, termed the ‘stochastic figure-ground’ stimulus that captures essential aspects of complex sounds in the natural environment. Previously, we showed that under controlled laboratory conditions, young listeners sampled from the university subject pool (n = 10) performed very well in detecting targets embedded in the stochastic figure-ground signal. Here, we presented a modified version of this cocktail party paradigm as a ‘game’ featured in a smartphone app (The Great Brain Experiment) and obtained data from a large population with diverse demographical patterns (n = 5148). Despite differences in paradigms and experimental settings, the observed target-detection performance by users of the app was robust and consistent with our previous results from the psychophysical study. Our results highlight the potential use of smartphone apps in capturing robust large-scale auditory behavioral data from normal healthy volunteers, which can also be extended to study auditory deficits in clinical populations with hearing impairments and central auditory disorders.

Normal adult aging and the contextual influences affecting speech and meaningful sound perception

It is widely accepted that hearing loss increases markedly with age, beginning in the fourth decade ISO 7029 (2000). Age-related hearing loss is typified by high-frequency threshold elevation and associated reductions in speech perception because speech sounds, especially consonants, become inaudible. Nevertheless, older adults often report additional and progressive difficulties in the perception and comprehension of speech, often highlighted in adverse listening conditions that exceed those reported by younger adults with a similar degree of high-frequency hearing loss (Dubno, Dirks, & Morgan) leading to communication difficulties and social isolation (Weinstein & Ventry). Some of the age-related decline in speech perception can be accounted for by peripheral sensory problems but cognitive aging can also be a contributing factor. In this article, we review findings from the psycholinguistic literature predominantly over the last four years and present a pilot study illustrating how normal age-related changes in cognition and the linguistic context can influence speech-processing difficulties in older adults. For significant progress in understanding and improving the auditory performance of aging listeners to be made, we discuss how future research will have to be much more specific not only about which interactions between auditory and cognitive abilities are critical but also how they are modulated in the brain.

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.

Contributions of experience to the development of musical processing in infancy

Full-term infants' performance in detection of melodic alterations appeared to be influenced by perceptual experience from 6 months to 1 year of age, and an experiment with infants born prematurely supported the hypothesis that experience affects music processing in infancy. These findings suggest parallel developmental tendencies in the perception of music and speech that may reflect general acquisition of perceptual abilities for processing of complex auditory patterns. This acquisition may contribute to the cultural enfranchisement of infants through perceptual experience.