Guo W Ren J Wang B Zhu Q (2015)

Mental fatigue plagues most individuals on a daily basis. Activities such as driving, working on assembly lines, copying information, and other tedious or repetitive tasks induce a “brain fog” that negatively impacts decision-making and responses. To alleviate the boredom of such tasks and thus reduce mental fatigue, many listen to music. Whether it’s projected by a car radio, personal music player, or loudspeakers, the soothing qualities of music are enjoyable and even beneficial when performing dull activities. A study conducted by a group of psychologists from the Shanghai University of Sport in China and the University of Wyoming in the United States indicates that relaxing music may reduce the symptoms of mental fatigue.

In “Effects of Relaxing Music on Mental Fatigue Induced by a Continuous Performance Task: Behavioral and ERPs Evidence,” psychologists investigated the correlation of listening to calming music while performing simple, repetitive tasks and their levels of mental fatigue. In this study, mental fatigue was defined as the sensation people may feel during and after extended periods of completing dull tasks. The sensations may manifest as anxiety, irritability, sleepiness, or other feelings that inhibit productivity and efficiency. Mental fatigue decreases attention and accuracy and increases response time, which are results of waning brain activity over lengthy periods of time. In the study, participants were asked to document their levels of mental fatigue on the Visual Analogue Scale (VAS), which, on a scale of one to one hundred, evaluates subjective feelings associated with mental fatigue. Previous studies have proven the VAS to be valid (Matthews Desmond, 2002).

As mental fatigue is so prevalent and universally relevant in workplaces, many studies have been conducted to gain deeper insight into this topic. For example, one study tested the effect of ingesting nutrients on the prevention of mental fatigue while another tried to alleviate mental fatigue by exposing participants to intermittent odors throughout the course of the study. Both found that the VAS scores of participants in these studies decreased, meaning their mental fatigue was reduced. Additionally, a study conducted by Arikan et al. in 1999 found that participants listening to well-known music maximized the allocation of mental resources while they performed tedious tasks. Based on past research, it is logical to assume that music can positively impact participants’ performances and decrease mental fatigue. Therefore, the psychologists conducting the study of the effect of relaxing music on mental fatigue alleviation hypothesized that relaxing music would result in lower VAS scores and improve cognitive-motor performance.

For this study, thirty-six paid undergraduate students participated in the experiment. There were equal numbers of males and females, and each was between the ages of eighteen and twenty-two. All of the participants also shared the traits of right-hand dominance, non-impaired vision and audition, a healthy body mass index, and a normal neurological and psychiatric history. The participants were randomly and equally assigned to the control and experimental groups. While each group performed the same sixty-minute fatigue-inducing task in dimly-lit rooms, the control group did its tasks in a quiet environment, and the experimental group was exposed to relaxing instrumental music played at forty decibels. Keyboards were placed beneath each of the participants’ right hands. The only noticeable deviance in the testing environments was the presence of music, the independent variable.

The experiment was comprised of three phases. The first consisted of a fifteen minute series of Go/No-Go tasks, which, according to Cognitive Atlas (2012), are tasks in which participants must either respond or not respond to a given stimulus based on given instructions. After this phase, participants completed the VAS. The second phase was sixty minutes long, and participants continuously performed the fatigue-inducing task. Another VAS was completed following the hour-long interval. The final phase was a repetition of the first.

During each of the phases, participants completed different Go/No-Go tasks. The first was designed to evaluate fatigue. In this sequence, the participants were instructed to press a button when one of the two configurations of lines identified as targets was displayed on the computer monitor placed about a meter from the participant’s face. The two other line configurations were defined as non-targets. These configurations are shown in Figure 1. The second phase’s task was engineered to induce fatigue. In the sixty-minute trial, letters were displayed sequentially on the monitor. The participants were directed to only press the button ‘1’ on a numeric keyboard when the probe letter (X) was presented after the cue letter (A), and in all other sequences, participants were supposed to respond by pressing the button ‘3.’ The last phase, as stated previously, was a replicated of the first. After each phase, participants were asked to rate their feelings on the VAS, which subjectively measured their concentration, anxiety, energy, confidence, irritability, nervousness, sleepiness, and talkativeness levels.

Following the study, all of the data was collected and condensed into charts and graphs displaying the scores on the fatigue scale, the reaction times, and the average event-related potentials (ERPs). In Table 2, the VAS scores of both the control and experimental music groups are shown before and after the task. For both groups, anxiety, irritability, and sleepiness significantly increased, but concentration, energy, and confidence significantly decreased following the fatigue-inducing tasks in phase two. However, the experimental group rated their feelings for concentration, energy, and confidence much higher than their control counterparts, and the music group’s scores on anxiety and irritability were much lower. It is conclusive that the fatigue-inducing task was effective, but the control group experienced more mental fatigue than the experimental group. Additionally, the music group’s reaction times stayed relatively consistent before and after the tasks while the control group’s reaction times increased following the tasks. Figures 3 and 4 present the ERPs for the Go/No-Go stimuli, which were measured by electroencephalograms that detected the brain responses to stimuli. Larger amplitudes for both Go and No-Go stimuli were recorded for the experimental group, but the control group’s No-Go amplitude was also larger than its Go amplitude. This suggests that the brain recognizes the No-Go stimuli more easily than the Go stimuli. Thus, the evidence collected in this study largely supports the researchers’ hypothesis that music alleviates the mental fatigue as demonstrated by the experimental group’s reports of milder symptoms of mental fatigue, faster reaction times, and greater ERP amplitudes suggesting more brain activity than the control group.

While both groups suffered from mental fatigue following the fatigue-inducing tasks, the experimental group experienced fewer negative impacts resulting from it. Despite the mental fatigue, the accuracies of both groups remained high throughout the course of the study. When studying the ERPs, the researchers believed that the participants’ attentional strength deteriorated over time, much like an overworked muscle; this effect was less pronounced in the music group than the control group. In the discussion, multiple studies were cited to corroborate this experiment’s evidence that music can reduce the deterioration of mental focus and minimize the effects of mental fatigue. This explains why many people listen to music while driving, studying, and working. Some limitations were also mentioned. The researchers admitted that a more difficult task may better induce mental fatigue. They also feared that relaxing music may simply suppress the effects of mental fatigue instead of alleviating it, so they suggested that this problem may be resolved by experimenting with a group that listens to a non-musical sound throughout the study.

In conclusion, this study took an in-depth approach at the effects of music on mental fatigue. Their results suggest that listening to music may decrease anxiety, irritability, and sleepiness while performing repetitive tasks. Music was also associated with more positive feelings, faster reaction times, and more efficient allocations of mental resources. While the study was small and had some limitations, the results have been supported by other studies. However, this provides room for future studies to gather more data on the nature of mental fatigue and how to best combat it. For now though, it would not be a bad idea to turn up the volume for classical music in the car, in the office, and even in the classroom.

References

Guo, W., Ren, J., Wang, B., Zhu, Q. (2015). Effects of Relaxing Music on Mental Fatigue

Induced by a Continuous Performance Task: Behavioral and ERPs Evidence.

PLos ONE 10(8): e0136446. doi:10.1371/journal.pone.0136446.

Lewis, M. (2012). Go/no-go task TASK. Retrieved September 24, 2017, from

http://www.cognitiveatlas.org/task/go/no-go_task

Matthews, G., Desmond, P. Task-induced fatigue states and simulated driving

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