Victoria J. Williamson

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.

Memory for pitch in congenital amusia: Beyond a fine-grained pitch discrimination problem

Congenital amusia is a disorder that affects the perception and production of music. While amusia has been associated with deficits in pitch discrimination, several reports suggest that memory deficits also play a role. The present study investigated short-term memory span for pitch-based and verbal information in 14 individuals with amusia and matched controls. Analogous adaptive-tracking procedures were used to generate tone and digit spans using stimuli that exceeded psychophysically measured pitch perception thresholds. Individuals with amusia had significantly smaller tone spans, whereas their digits spans were a similar size to those of controls. An automated operation span task was used to determine working memory capacity. Working memory deficits were seen in only a small subgroup of individuals with amusia. These findings support the existence of a pitch-specific component within short-term memory and suggest that congenital amusia is more than a disorder of fine-grained pitch discrimination.

Faster decline of pitch memory over time in congenital amusia.

Congenital amusia (amusia, hereafter) is a developmental disorder that impacts negatively on the perception of music. Psychophysical testing suggests that individuals with amusia have above average thresholds for detection of pitch change and pitch direction discrimination; however, a low-level auditory perceptual problem cannot completely explain the disorder, since discrimination of melodies is also impaired when the constituent intervals are suprathreshold for perception. The aim of the present study was to test pitch memory as a function of (a) time and (b) tonal interference, in order to determine whether pitch traces are inherently weaker in amusic individuals. Memory for the pitch of single tones was compared using two versions of a paradigm developed by Deutsch (1970a). In both tasks, participants compared the pitch of a standard (S) versus a comparison (C) tone. In the time task, the S and C tones were presented, separated in time by 0, 1, 5, 10, and 15 s (blocked presentation). In the interference task, the S and C tones were presented with a fixed time interval (5 s) but with a variable number of irrelevant tones in between 0, 2, 4, 6, and 8 tones (blocked presentation). In the time task, control performance remained high for all time intervals, but amusics showed a performance decrement over time. In the interference task, controls and amusics showed a similar performance decrement with increasing number of irrelevant tones. Overall, the results suggest that the pitch representations of amusic individuals are less stable and more prone to decay than those of matched non-amusic individuals.

How do earworms start? Classifying the everyday circumstances of Involuntary Musical Imagery

Involuntary Musical Imagery (INMI) or “earworms” describes the experience whereby a tune comes into the mind and repeats without conscious control. The present article uses an inductive, generative, grounded theory-based qualitative analysis to classify reports of everyday INMI circumstances, and creates graphical models that determine their relative frequency within two population samples; listeners to the BBC radio station 6 Music and an online survey. Within the two models, four abstract categories were defined that described the characteristics of the circumstances surrounding the onset of INMI episodes; Music exposure, Memory triggers, Affective states, and Low attention states respectively. We also note the variety of musical media by which exposure to a tune results in an INMI episode and discuss the impact of musical engagement on INMI experiences. The findings of the present study are considered within a framework of involuntary retrieval theory from both the autobiographical and semantic memory literatures. In addition, the results highlight the potential facilitative effects of varying affective and attentional states on INMI episodes.

Electrophysiological correlates of melodic processing in congenital amusia

Music listening involves using previously internalized regularities to process incoming musical structures. A condition known as congenital amusia is characterized by musical difficulties, notably in the detection of gross musical violations. However, there has been increasing evidence that individuals with the disorder show preserved musical ability when probed using implicit methods. To further characterize the degree to which amusic individuals show evidence of latent sensitivity to musical structure, particularly in the context of stimuli that are ecologically valid, electrophysiological recordings were taken from a sample of amusic and control participants as they listened to real melodies. To encourage them to pay attention to the music, participants were asked to detect occasional notes in a different timbre. Using a computational model of auditory expectation to identify points of varying levels of expectedness in these melodies (in units of information content (IC), a measure which has an inverse relationship with probability), ERP analysis investigated the extent to which the amusic brain differs from that of controls when processing notes of high IC (low probability) as compared to low IC ones (high probability). The data revealed a novel effect that was highly comparable in both groups: Notes with high IC reliably elicited a delayed P2 component relative to notes with low IC, suggesting that amusic individuals, like controls, found these notes more difficult to evaluate. However, notes with high IC were also characterized by an early frontal negativity in controls that was attenuated in amusic individuals. A correlation of this early negative effect with the ability to make accurate note expectedness judgments (previous data collected from a subset of the current sample) was shown to be present in typical individuals but compromised in individuals with amusia: a finding in line with evidence of a close relationship between the amplitude of such a response and explicit knowledge of musical deviance.

Detection of the arcuate fasciculus in congenital amusia depends on the tractography algorithm

The advent of diffusion magnetic resonance imaging (MRI) allows researchers to virtually dissect white matter fiber pathways in the brain in vivo. This, for example, allows us to characterize and quantify how fiber tracts differ across populations in health and disease, and change as a function of training. Based on diffusion MRI, prior literature reports the absence of the arcuate fasciculus (AF) in some control individuals and as well in those with congenital amusia. The complete absence of such a major anatomical tract is surprising given the subtle impairments that characterize amusia. Thus, we hypothesize that failure to detect the AF in this population may relate to the tracking algorithm used, and is not necessarily reflective of their phenotype. Diffusion data in control and amusic individuals were analyzed using three different tracking algorithms: deterministic and probabilistic, the latter either modeling two or one fiber populations. Across the three algorithms, we replicate prior findings of a left greater than right AF volume, but do not find group differences or an interaction. We detect the AF in all individuals using the probabilistic 2-fiber model, however, tracking failed in some control and amusic individuals when deterministic tractography was applied. These findings show that the ability to detect the AF in our sample is dependent on the type of tractography algorithm. This raises the question of whether failure to detect the AF in prior studies may be unrelated to the underlying anatomy or phenotype.

The Relationship between Pitch and Space in Congenital Amusia.

Congenital amusia manifests as a lifelong difficulty in making sense of musical sound. The extent to which this disorder is accompanied by deficits in visuo-spatial processing is an important question, bearing on the issue of whether pitch processing draws on supramodal spatial representations. The present study assessed different aspects of visuo-spatial processing with a range of tasks (Shepard-Metzler Mental Rotation, Corsi Blocks Task, Visual Patterns Test) in 14 amusics and matched controls. The absence of a group difference on any of these tasks fails to support a previous claim that the disorder is strongly related to deficits in spatial processing. However, a subgroup of amusics, with significantly elevated thresholds on a pitch direction discrimination task relative to the rest of the group, were slower, but equally accurate, at Mental Rotation. This finding is discussed in relation to the nature of supramodal representations of contour and strategies for dynamic mental transformation.

Background music can aid second language learning

The presence of music can both help and hinder performance on a concurrent cognitive task. Music that is low in complexity has been associated with improved performance on language learning tasks, although previous studies have typically used artificial stimuli or tested only short-term recognition. The present study examined the effect of background music as part of an ecologically valid two-week second language learning trial. Participants took a beginners’ CD-based course in either Mandarin Chinese or Arabic, and matched groups (age, gender, verbal intelligence, musical training and working memory ability) were randomly assigned to a CD that contained accompanying music or not. Individuals who chose to learn Chinese performed better on all outcome tests compared to those who learned Arabic. Within the Chinese learners, those who received music CDs performed significantly better on tests of recall and translation compared to those who received no music CDs. No music effects were observed in the Arabic learners or on pronunciation ability in Chinese. This study demonstrates that the presence of certain music can facilitate the first stages of language learning in the real world.

Anodal transcranial direct current stimulation over the supramarginal gyrus facilitates pitch memory.

Functional neuroimaging studies have shown activation of the supramarginal gyrus during pitch memory tasks. A previous transcranial direct current stimulation study using cathodal stimulation over the left supramarginal gyrus reported a detrimental effect on short‐term pitch memory performance, indicating an important role of the supramarginal gyrus in pitch memory. The current study aimed to determine whether pitch memory could be improved following anodal stimulation of the left supramarginal gyrus. The performances of non‐musicians on two pitch memory tasks (pitch recognition and recall) and a visual memory control task following anodal or sham transcranial direct current stimulation were compared. The results show that, post‐stimulation, the anodal group but not the control group performed significantly better on both pitch memory tasks; performance did not differ on the face memory task. These findings provide strong support for the causal involvement of the left supramarginal gyrus in the pitch memory process, and highlight the potential efficacy of transcranial direct current stimulation as a tool to improve pitch memory.

Sticky tunes: how do people react to involuntary musical imagery?

The vast majority of people experience involuntary musical imagery (INMI) or ‘earworms’; perceptions of spontaneous, repetitive musical sound in the absence of an external source. The majority of INMI episodes are not bothersome, while some cause disruption ranging from distraction to anxiety and distress. To date, little is known about how the majority of people react to INMI, in particular whether evaluation of the experience impacts on chosen response behaviours or if attempts at controlling INMI are successful or not. The present study classified 1046 reports of how people react to INMI episodes. Two laboratories in Finland and the UK conducted an identical qualitative analysis protocol on reports of INMI reactions and derived visual descriptive models of the outcomes using grounded theory techniques. Combined analysis carried out across the two studies confirmed that many INMI episodes were considered neutral or pleasant, with passive acceptance and enjoyment being among the most popular response behaviours. A significant number of people, however, reported on attempts to cope with unwanted INMI. The most popular and effective behaviours in response to INMI were seeking out the tune in question, and musical or verbal distraction. The outcomes of this study contribute to our understanding of the aetiology of INMI, in particular within the framework of memory theory, and present testable hypotheses for future research on successful INMI coping strategies.