Long-term musical training may improve different forms of visual attention ability

Highlights

• Orchestra musicians performed better than non-musicians in visual attention tests.

• They showed superior performance in selective, divided and sustained attention.

• This advantage could not be explained by better sensorimotor integration.

• Musicians who began their musical studies earlier presented better reaction times.

• These data illustrate the possible cognitive benefits of long-term musical training.

Abstract

Many studies have suggested that structural and functional cerebral neuroplastic processes result from long-term musical training, which in turn may produce cognitive differences between musicians and non-musicians. We aimed to investigate whether intensive, long-term musical practice is associated with improvements in three different forms of visual attention ability: selective, divided and sustained attention. Musicians from symphony orchestras (n = 38) and non-musicians (n = 38), who were comparable in age, gender and education, were submitted to three neuropsychological tests, measuring reaction time and accuracy. Musicians showed better performance relative to non-musicians on four variables of the three visual attention tests, and such an advantage could not solely be explained by better sensorimotor integration. Moreover, in the group of musicians, significant correlations were observed between the age at the commencement of musical studies and reaction time in all visual attention tests. The results suggest that musicians present augmented ability in different forms of visual attention, thus illustrating the possible cognitive benefits of long-term musical training.

Introduction

Many investigations have reported structural and functional changes in the brains of musicians, involving several regions, such as the corpus callosum (Schlaug, Jäncke, Huang, Staiger, & Steinmetz, 1995), motor cortex (Amunts et al., 1997), somato-sensory cortex (Elbert, Pantev, Wiendbruch, Rockstroh, & Taub, 1995), auditory cortex (Pantev et al., 1998) and hippocampus (Herdener et al., 2010), which occur as a result of many years of musical practice.

The structural and functional neuroplastic processes verified in the brains of musicians may influence their cognitive functioning, revealing differences in comparison to non-musicians. Several works (e.g. Piro and Ortiz, 2009, Rauscher and Zupan, 2000, Schellenberg, 2004, Vaughn, 2000) have demonstrated positive associations between formal musical training in children and improvements in non-musical cognitive abilities, such as literacy, mathematics and visual–spatial reasoning, as well as general intelligence. However, fewer works have addressed this issue in adults.

Some of these studies have suggested the presence of enhanced visual cognition in adult musicians. Brochard, Dufour, and Després (2004) investigated visual–spatial abilities, using a neuropsychological test in which subjects were required to detect the position of a target dot relative to vertical and horizontal reference lines flashed on a screen. In one condition (perception condition), the reference line remained on the screen until the dot was displayed, while in a second condition (imagery condition), the line disappeared before the target dot was presented, requiring subjects to keep a mental image of the reference line. In both conditions, musicians exhibited shorter reaction times when compared to controls, suggesting the presence of augmented visual–spatial abilities in the former group.

The comparison of saccadic eye movements in musicians and non-musicians also revealed important aspects of music reading practice. As noted by Kopiez and Galley (2002), the pattern of saccadic eye movements can be used as an indicator of mental disabilities, as well as a measure of mental processing speed. Kopiez and Galley (2002) and Gruhn et al. (2006) investigated saccadic eye movements during oculomotor tasks in adult subjects and reported more efficient oculomotor strategies in musicians when compared to non-musicians.

In a previous study (Rodrigues, Guerra, & Loureiro, 2007), we evaluated visual attention ability in orchestra musicians and non-musicians, using a neuropsychological test that required the ability to respond to sequentially presented luminous stimuli with specific motor reactions: the lighting of several colored lamps, which was responded to with correspondent key pressing, using the preferred hand only; and the lighting of two white lamps, positioned at the right and left of the subject, which was responded to with correspondent foot-switches. This test was applied twice (conditions 1 and 2), in which the second test (condition 2) was applied concomitantly with other randomly changing visual stimuli presented in a video, demanding verbal responses of subjects to each change. Musicians showed a higher percentage of correct responses in condition 1 and, although no difference in accuracy was observed between the groups in condition 2, musicians showed shorter reaction times for verbal responses, suggesting the presence of an augmented divided visual attention ability.

Patston, Corballis, Hogg, and Tippett (2006) compared right-handed musicians and non-musicians in a line-bisection task. In this task, neurologically intact right-handers show a slight yet reliable tendency to bisect approximately 2% to the left of the true center, which has been attributed to the dominance of the right hemisphere for visual–spatial attention. These authors found that musicians showed a slight rightward bias, while non-musicians showed greater deviation to the left, and that musicians bisected the lines more accurately and with smaller intermanual differences than the control group. The researchers suggested that the left hemispheres of musicians may present an increased ability to perform cognitive functions that are usually right-hemisphere dominant, resulting in a more balanced visual–spatial attention.

In another study, Patston, Hogg, and Tippett (2007) investigated the lateralization of visual attention in musicians and non-musicians, comparing reaction times and accuracy to stimuli presented to the left and right of a vertical line – a similar task to that used by Brochard et al. (2004). While both musicians and non-musicians performed more accurately for the left sided-stimuli, musicians were significantly more accurate than controls for the right-sided stimuli, and they also had faster reaction times overall. According to the authors, these results indicate a more balanced attentional capacity in musicians, as well as enhanced visual-motor ability, which is consistent with previous research.

Stoesz, Jakobson, Kilgour, and Lewycky (2007) verified the presence of increased visual processing of local details in musicians when compared to non-musicians by utilizing disembedding and constructional tasks. According to the authors, this phenomenon may be related to changes in the neural system involved in controlling exploratory eye movements and shifts of visual attention. Jakobson, Lewycky, Kilgour, and Stoesz (2008) found a superior visual memory in musicians relative to non-musicians and hypothesized that this result could be due to improvements in supporting processes of visual attention, to the increased ability to hold and manipulate visual images in working memory, or even to the superior use of high-level strategic memory processes by musicians.

The aim of our study was to investigate whether intensive, long-term musical practice could be associated with improvements in three forms of visual attention ability: selective, divided and sustained attention. The first form refers to the ability to direct attention to a target stimulus, which was presented amongst irrelevant stimuli, and the second form relates to the capacity to attend concomitantly to two or more sources of stimulation, and the third form corresponds to an alertness state in detecting and responding to changes in stimuli (Muir, 1996). Selective attention appears to be expressed as an enhancement of activity in the neural pathways that are relevant to task performance (Madden et al., 1997). For instance, attending selectively to the shape and velocity of visually presented forms is associated with activation in the occipitotemporal and occipitoparietal regions, respectively (Corbetta, Miezin, Dobmeyer, Shulman, & Petersen, 1991). However, dividing attention among several stimulus dimensions activates regions outside of the visual system, in the anterior cingulated gyrus and the prefrontal cortex (Corbetta et al., 1991). Activation of the prefrontal cortex increases with the task difficulty level, and it may be viewed as an increasing requirement for the maintenance of attention in working memory, for example (Grady et al., 1996). During sustained attention performance, studies have demonstrated activation in the anterior cingulate, dorsolateral prefrontal and parietal cortices (e.g. Coull, 1998, Fink et al., 1997). Moreover, a reduction in the activity of frontotemporoparietal regions during the task has been associated with a decrease in vigilance level (e.g. Coull, Frith, Frackowiak, & Grasby, 1998).

As previously mentioned, some studies have investigated associations between musical training and visual attention ability, but research involving such cognitive function in a more comprehensive manner, i.e., addressing more than one visual attention form, is still nonexistent. As musical practice may involve different attentional demands at different moments, studies that investigate the distinct forms of visual attention ability are needed. We compared the performance of musicians with that of non-musicians in tasks involving selective, divided and sustained visual attention ability by utilizing different neuropsychological tests, and we hypothesized that musical training, given its multifaceted nature, may be associated with improved attentional skills.