Why do we daydream? Besides from deciding how to spend our lottery win or calculating an escape route in time for the zombie apocalypse, of course.
Well, new research, published in the Proceedings of National Academy of Sciences, suggests the neuro-network that plays a role in daydreaming also allows us to perform routine tasks more efficiently.
It all comes down to the Default Mode Network (DMN), which is most active when we're not doing anything. In addition to daydreaming, we know this part of the brain is involved in creativity, and thinking about the past and future. We also know that abnormal activity in the DMN is associated with Alzheimer’s disease, schizophrenia, attention-deficit/hyperactivity disorder (ADHD), and disorders of consciousness (i.e. comas, vegetative states, and minimally conscious minds). But aside from that, the DMN is not very well understood and scientists haven't (until now) been able to establish its function in human cognition.
“Rather than waiting passively for things to happen to us, we are constantly trying to predict the environment around us,” Dr Deniz Vatansever, who co-authored the study as part of his PhD thesis, said in a statement.
This is where the DMN kicks in.
“It is essentially like an autopilot that helps us make fast decisions when we know what the rules of the environment are. So for example, when you’re driving to work in the morning along a familiar route, the default mode network will be active, enabling us to perform our task without having to invest lots of time and energy into every decision,” Vatansever added.
For the study, the scientists monitored the brain activity of 28 volunteers as they performed a simple card game. The participants were asked to match a target card with one of four more cards presented to them. To make things tougher, the researchers didn't explain the rules - the cards had to match by color, shape or number.
Interestingly, the scans revealed a shift in brain activity from the dorsal attention network (DAN) to the DMN when the participants worked out the rules and began to apply them to the game. They also showed that the stronger the activity linking the DMN to areas in the brain involved in memory (say, the hippocampus), the quicker and more accurate the participant was when performing the task.
This backs up Daniel Kahneman's theory in his book Thinking, Fast and Slow, ie that we each have two thinking processes: one slow and conscious, and the other fast and subconscious. The DMN, the researchers say, is most likely associated with the latter.