The silent gorilla: Intense concentration leaves us 'deaf' to the world around us

(Medical Xpress) -- Concentrating closely on a conversation can leave us ‘deaf’ to other sounds, reveals Dr Polly Dalton from the Department of Psychology at Royal Holloway, University of London.

Participants in her experiment – the first of its kind - completely failed to notice a clearly audible ‘gorilla man’ when they were paying attention to a different conversation.

“We’re much less aware of the world around us than we tend to think” says Dr Dalton. “This research demonstrates that we can miss even very surprising and distinctive sounds when we are paying attention to something else.”

Dr Dalton and research associate Nick Fraenkel created a lifelike, three-dimensional auditory scene, containing one conversation between two men and another between two women. Halfway through the recording they introduced a ‘gorilla man’, who walked through the scene repeating the phrase “I’m a gorilla!” for 19 seconds. People who were concentrating on the men’s conversation were much better at detecting the ‘gorilla man’, but most of those listening to the women’s discussion completely failed to notice him at all.

Dr Dalton says: “The ‘invisible gorilla’ effect, where people fail to see a person in a gorilla suit walking through a basketball game, is now quite well-known. Our study provides the first demonstration of a similar ‘silent gorilla’ effect in hearing.

“We were surprised to find such extreme effects with a listening task, because people often think of hearing as an ‘early warning system’ that can alert us to unexpected events that occur out of sight. The fact that a lack of attention can cause people to miss even distinctive and long-lasting sounds questions this view. This has real-world implications in suggesting, for example, that talking on your mobile phone is likely to reduce your awareness of traffic noises.”

The research, funded by the ESRC, is published in the journal Cognition.