"There is a common belief that observers can experience changes directly with their mind, without needing to rely on the traditional physical senses such as vision, hearing, taste, smell and touch to identify it. This alleged ability is sometimes referred to as a sixth sense or ESP.

"We were able to show that while observers could reliably sense changes that they could not visually identify, this ability was not due to extrasensory perception or a sixth sense," said Howe.

The test, known as a flicker paradigm, involved showing participants a picture for 1.5 seconds, followed by a one-second gap, followed by the same pictures as before, but with a slight change, for a further 1.5 seconds. For example, the first picture might depict a woman without glasses, whereas the second might depict the same woman, but wearing glasses. Participants were then asked to describe the differences they noticed in the pictures, drawing from a list of possible answers.

Results showed participants were good at detecting changes, even when they could not identify exactly what had changed -- instead, they reported "sensing" or "feeling" something was different. 

This inability to spot specific differences between two images that are identical except for one change is known as "change blindness" and is often the result of obstructions in the visual field, eye movements, a change of location, or a lack of attention. It is this ability to detect changes without being able to identify exactly what has changed that can often lead people to incorrectly believe they have a "sixth sense".