City research suggests that synaesthesia may be behind the ‘bouncing pylon’ phenomenon and it may be more common that we think.

Published (Updated )

Researchers from City, University of London believe that synaesthesia may be behind the recent phenomenon where people hear a ‘thudding’ noise when viewing a silent GIF of electricity pylons bouncing.

According to Dr Elliot Freeman and Chris Fassnidge, a PhD researcher in Dr Freeman’s lab in the Department of Psychology at City, the effect seen is due to how our senses work, as this illusion is an example of a type of ‘hearing-motion’ synaesthesia. Such effects occur when the senses, such as hearing and sight, are crossed in the brain.

Currently the only lab in the world to be actively researching this phenomenon, Dr Freeman and colleagues call this effect visually-evoked auditory response, or vEAR for short.

It is thought that the effect may arise as humans are better at recording sound than images, therefore the ability to recode visual signals as sounds would take advantage of such abilities.

In a recent study, they also found that such ‘hearing-motion’ synaesthesia occurred in 22 per cent of people when tested and it is thought that they may occur subliminally, disrupting detection of real auditory signals.

This makes the effect more common than other types of synaesthesia – for example colour and sound – as these types only occur in around 4 percent of the population.

"Does anyone in visual perception know why you can hear this gif? 

— Lisa DeBruine (@lisadebruine) December 2, 2017

Speaking about the phenomenon to The Telegraph, Chris Fassnidge said:

"I suspect the noisy gif phenomenon is closely related to what we call the Visually-Evoked Auditory Response, or vEAR for short. This is the ability of some people to hear moving objects even though they don't make a sound, which may be a subtle form of synaesthesia - the triggering of one sense by another.

"We are constantly surrounded by movements that make a sound, whether they are footsteps as people walk, lip movements while they talk, a ball bouncing in the playground, or the crash as we drop a glass. There is some evidence to suggest that synaesthetic pairings are, to some extent, learnt during infancy. I might assume I am hearing the footsteps of a person walking on the other side of the street, when really the sound exists only in my mind.

"So this may be a common phenomenon because the sound makes sense, but for that exact reason we may not even know we have this unusual ability until the noisy gif suddenly came along in the last few years. What determines who experiences vEAR and how intensely is probably individual differences in how our brain is wired."

Dr Elliot Freeman, a senior lecturer in the Department at Psychology at City, University of London, said to Press Association:

“I believe the phenomenon is correlated to a form of synaesthesia where the sense of sight triggers a sense of hearing. Synaesthesia is actually quite rare, as around 4% of the population possesses some form of the condition, but the strong motion energy in the shaking pylon GIF, paired with the expectation of something falling, triggers the auditory cortex – the region in the brain that processes sound – explaining why so many people are able to hear the ‘thud’.”

Take part in a study on vEAR