Spot the dogs (Image: Gandee Vasan/Getty)

It’s a case of hear no object, see no object. Hearing the name of an object appears to influence whether or not we see it, suggesting that hearing and vision might be even more intertwined than previously thought.

Studies of how the brain files away concepts suggest that words and images are tightly coupled. What is not clear, says Gary Lupyan of the University of Wisconsin in Madison, is whether language and vision work together to help you interpret what you’re seeing, or whether words can actually change what you see.

Lupyan and Emily Ward of Yale University used a technique called continuous flash suppression (CFS) on 20 volunteers to test whether a spoken prompt could make them detect an image that they were not consciously aware they were seeing.


CFS works by displaying different images to the right and left eyes: one eye might be shown a simple shape or an animal, for example, while the other is shown visual “noise” in the form of bright, randomly flickering shapes. The noise monopolises the brain, leaving so little processing power for the other image that the person does not consciously register it, making it effectively invisible.

Wheels of perception

In a series of CFS experiments, the researchers asked volunteers whether or not they could see a specific object, such as a dog. Sometimes it was displayed, sometimes not. When it was not displayed or when the image was of another animal such as a zebra or kangaroo, the volunteers typically reported seeing nothing. But when a dog was displayed and the question mentioned a dog, the volunteers were significantly more likely to become aware of it. “If you hear a word, that greases the wheels of perception,” says Lupyan: the visual system becomes primed for anything to do with dogs.

In a similar experiment, the team found that volunteers were more likely to detect specific shapes if asked about them. For example, asking “Do you see a square?” made it more likely than that they would see a hidden square but not a hidden circle.

James McClelland of Stanford University in California, who was not involved in the work, thinks it is an important study. It suggests that sight and language are intertwined, he says.

Lupyan now wants to study how the language we speak influences the ability of certain terms to help us spot images. For instance, breeds might be categorised differently in different languages and might not all become visible when volunteers hear their language’s word for “dog”. He also thinks textures or smells linked to an image might have a similar effect on whether we perceive it as words.

Journal reference: PNAS, DOI: 10.1073/pnas.1303312110