Just thinking about the past or future could literally move you. This mental time travel was revealed in a new study in which participants swayed backward when thinking of the past and forward with future thoughts.
The phenomenon is a not-so-surprising aspect of a uniquely human trait. The ability to subjectively travel though time, called chronesthesia, sets us apart from other animals, the researchers say. And now their results suggest our perceptions of time are tightly coupled with space.
"This is the first demonstration that when we think about time we physically move though space, whether that's engaged though areas of the brain or manifested throughout the whole body is an open question," said Lynden Miles of the University of Aberdeen in Scotland.
Miles and Aberdeen colleagues Louise Nind and Neil Macrae fitted 20 participants with a motion sensor while they imagined future or past events. After just 15 seconds, participants who were recalling the past had swayed backward an average of about 0.7 inches (1.5 to 2 mm), while the future thinkers leaned forward about 0.1 inches (3 mm).
Participants were blindfolded to induce swaying in all directions so that the movements were large enough to detect, though Miles says this doesn't change the results.
"There is no reason that posture in a lab should be any different from posture in the real world," Miles told LiveScience. "My guess is we sway just as much in the real world as we do in the lab."
To figure out what's behind the space-time link, Miles and his colleagues hope to study this same phenomenon in other cultures.
"We have a lot of language to suggest the future is in front of us and the past behind us," Miles said.
But in some other cultures, such as those who speak Aymara (an Amerindian language of the Andes), the future is described as being behind them with the past in front. If such individuals sway backward when thinking about future events, that might suggest this behavior is learned and a consequence of how people think and talk about time.
The results are detailed online in the journal Psychological Science.