The mysterious wandering brain

The human brain loves a mystery; why else would there be shelf upon shelf in bookshops devoted to crime novels? Why else would production companies still see the value in making yet another version of an Agatha Christie novel for the small screen? Why would series like Midsomer Murders go indefinitely, and implausibly, on and on and on? Yes, the human brain loves a mystery, but why? Perhaps it is because the brain is a mystery unto itself and, as the human brain searches for answers as to how it works, it feels somehow comforted by other, more repetitive, mysteries in the world outside. Yet part of the mystery that is the human brain, and the mind that inhabits around about it, has been dispelled in a new piece of research.

The study involved participants being treated with transcranial direct current stimulation (tDCS), a non-invasive and painless procedure that uses low level electrical signals to stimulate specific brain regions. The Harvard University researchers focused their tDCS on the frontal lobe as this is the part of the brain that has been implicated in mind wandering as well as being part that allows us to plan for the future. In other experiments to create a point of comparison the researchers used tDCS to stimulate the occipital cortex, a visual processing centre at the back of the brain. On some occasions no tDCS was used.

While their brains were being stimulated the subjects were asked to track and respond to numerals flashed on a computer screen. Every so often they were asked to respond to a “thought probe” on the screen that asked them to rate from 1 to 4 the extent to which they were experiencing spontaneous thoughts unrelated to the task they had been given.

It was shown that stimulating the frontal lobe did promote mind wandering but surprisingly did not reduce performance on the task at hand, in fact, it improved it. The researchers think this is because mind wandering stimulates massive default network within the brain that goes across many brain areas. Mind wandering actually enhanced cognitive ability by allowing a mental escape from a boring task but keeping the mind on track at the same time. No wonder then that the same area of the brain controls mind wandering as well as cognitive projection and planning.

So in all, it seems that day-dreaming or mind-wandering can actually help you with assigned tasks. Is that a mind mystery dispelled or another mystery revealed?