While it may be our eyes that physically see, it’s our brain that eventually interpret this information into sight. This means that one entity could be perceived differently depending on the viewer. Working off this idea, a recent study has shown that the musicians who can read music percieve the world a bit differently than everyone else.

A recent study conducted by researchers from Vanderbilt University designed an experiment to further investigate how our brain creates our view of the outside world based on information it receives from our eyes with specific emphasis on how supplementary information, such as sound, can change our visual perception. The team used a classic test known as a "binocular rivalry" to explore this theory, according to a press release. This test is often used because it presents the brain with a clear visual conflict that it is forced to resolve.

The researchers presented volunteers who could read music and those who could not with a scrolling musical score in one eye and an array of moving contours in the other. Because it is not possible to view the two different slides simultaneously the brain must chose which image to focus on. The volunteers were then asked to press one button when they were viewing the contours and other when they viewed the musical score.

As reported by the press release, both images were viewed equally for the same amount of time, with each image changing perceptual dominance for the same time period. It was not until the researchers asked the volunteers to perform the same task while listening to music that the results between those who read music and those who cannot began to differ.

When volunteers were asked to listen to a simple tune while completing the task those who read music reported that they spent more time watching the visual score and less time watching contours. People unable to read music saw no change in their viewing habits.

The study also revealed a second key finding, showing that playing the melody prolonged the periods when the musical score dominated a person's perception but it did not cut short the periods when the moving contours were predominant.

"What this tells us is that the kind of information the brain uses to interpret what we see around us includes abstract symbolic input such as music notation," said Blake. "However, this kind of input is only effective while an individual is aware of it," said Randolph Blake, director of the study, in the press release.

Source: Lee M, Blake R, Kim S, Kim C. Melodic sound enhances visual awareness of congruent musical notes, but only if you can read music. PNAS. 2015