Instead, people can reliably sense when a change has occurred, even when they could not see exactly what had changed; for example, a person might notice a general change in someone's appearance but not be able to identify that the person had had a haircut.
It's not ESP, the researchers said, but rather -- as proven in their scientific study -- that people can reliably sense changes that they cannot visually identify.
"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," Piers Howe from the Melbourne School of Psychological Sciences said. "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," he said.
In the study, participants were presented with pairs of color photographs, both of the same female, but in some cases her appearance -- her hairstyle, for example -- would be different in the two photographs.
Results showed the participants could generally detect when a change had occurred even when they could not identify exactly what had changed, the researchers said.
They might "feel" or "sense" that a change had occurred without being able to visually identify it, the researchers said, but that could be explained without invoking an extrasensory mechanism.