Apparent motion steers the wandering mind

Daydreaming is a critical component of conscious experience. The mind can perform mental time travel – it occasionally strays from the present moment, to recollect an experience from the near or distant past, or to imagine an event that has not yet taken place. We know that thinking about the future is dependant on memory, because patients with amnesia cannot imagine new experiences. It involves piecing together fragments of past experiences to generate a plausible simulation of what might happen. This may have been an important development in human evolution, as it enables us anticipate a likely outcome and to plan the best possible course of action.

Space and time are intimately linked in the mind, and this is reflected in our metaphors. We often say that we are thinking back to a past event, or looking forward to one that will take place in the future. But the mind and body are also closely linked: think about a past experience, and you might find yourself moving backwards. A new study suggests that this can be reversed, by showing that apparent motion can influence the direction of the mind’s wanderings. Thus, moving backwards could evoke long lost memories, while moving forward might make you think about the future.

Does time dilate during a threatening situation?

“WHEN a man sits with a pretty girl for an hour,” said Albert Einstein, “it seems like a minute. But let him sit on a hot stove for a minute, and it’s longer than any hour.” Einstein was describing one of the most profound implications of his Theory of General Relativity – that the perception of time is subjective. This is something we all know from experience: time flies when we are enjoying ourselves, but seems to drag on when we are doing something tedious.

The subjective experience of time can also be manipulated experimentally. Visual stimuli which appear to be approaching are perceived to be longer in duration than when viewed as static or moving away. Similarly, participants presented with a stream of otherwise identical stimuli, but including one oddball, or “deviant”, stimulus, tend to perceive the deviant stimulus as lasting longer than the others. The underlying neural mechanisms of this are unknown, but now the first neuroimaging study of this phenomenon implicates the involvement of brain structures which are thought to be required for cognitive control and subjective awareness.