As many as one-fifth of people have a condition that causes them to ‘hear’ silent movements or flashes, according to a new study.
The report from City University London describes an incredibly common form of synaesthesia, a phenomenon that causes unusual sensory experiences.
The specific type examined for the new research affects a significantly large number of people, but less than five percent of people live with the other forms of synaesthesia.
The scientists behind the new analysis think that some people hear silent movement when information from the visual parts of their brains gets ‘leaked’ to auditory areas of the mind.
The report described the effect, called visually-evoked auditory response (vEAR) as ‘barely known to science’, and it claimed vEAR is more common than other types of synaesthesia that cause, for example, sounds to make people see a specific colors.
vEAR, by contrast, leads people who see flashing lights or motion to hear vivid sounds.
The report said: ‘The survival of this association may explain links between sound and vision, such as why we like to listen to music synchronized with flashing lights or dance.
‘The effect also provides a good way to learn about what’s happening in the brain in people with synaesthesia, with vEAR’s high prevalence making it easier to investigate the mechanisms behind such cross-sensory perception.’
For the new research, published in Cortex, scientists surveyed 4,128 people online.
The study was the first of its kind to analyze vEAR, and all participants watched 24 video clips that did not feature sound for the research.
The clips depicted non-abstract subjects engaging in ‘slow, fast, smooth or sudden movements’, the report said.
It continued: ‘This included a ballet dancer performing a pirouette and a hammer hitting a nail. The survey also included additional multiple choice questions asking about demographics, experience of vEAR and other traits.’
Twenty-one percent of the participants said they had experienced vEAR before the time of the survey.