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Why do we daydream?

by Dyani Lewis

You might feel daydreaming is an indulgence that serves little purpose in your busy life. But research into how and why your mind wanders reveals the importance of these mental detours.


We've all been there, you're in the middle of conversation when someone asks you a question and you realise you are in another world – or possibly on the other side of this one.

But have ever wondered why your mind sometimes drifts away? Researchers have been looking for the answer to this question for close to 60 years.

Dr Muireann Irish works at Neuroscience Research Australia, studying the neurobiology of daydreaming in people with dementia, she says daydreaming gets a bad rap.

"Many people view daydreaming as being detrimental or a waste of time or a bad use of mental power," she says.

But the frequency with which many of us daydream – estimates suggest that up to half of our waking lives are spent daydreaming – "really does suggest that it has some sort of evolutionary adaptive value," says Irish.

Why do we daydream?

In trying to figure out why we daydream, there are clues to be found in what we daydream about.

"Just about every thought that people have is related directly or indirectly to one of their goals," says Professor Eric Klinger from the University of Minnesota, who has been researching daydreaming and mind wandering since the 1970s.

"Most of these goals are extremely basic and many of them are short-term," he says, "like trying to remember to buy tomatoes on the way home or worrying about what you're going to say to somebody."


Dreaming about the future

Most of your daydreaming focuses on things that might happen in the future.

"We plan ahead, we think about outcomes of decisions, we think about what we might do at the weekend, what we might do next week," says Irish. But you also think about your lif in the more distant future, considering whom you might marry or where you might live.

This process can help prepare us for that future, whether it be in a few minutes time, or further down the track. "It's a rehearsal mechanism," says Klinger. "It's spontaneous, it's not a deliberate rehearsal, but it plays a role of priming us."

In socially-oriented daydreaming, "we can think about the feelings, the intentions and the thoughts that other people may have," says Irish. "We can work through if a colleague seemed dismissive towards us, that maybe it's nothing to do with us but we can put it into context of extra things that are going on in their lives."

Daydreaming can also be a source of creative inspiration. "We often discover solutions or better ways of doing things than we would have, had we not had the mind-wandering space," says Klinger.

Irish agrees. "Standing in the shower, wondering what you're going to do at work that day, sometimes we can have this breakthrough that we never would have achieved if we'd laboured on the problem using a very attentive, focused approach."

What happens to the brain when your mind wanders

Modern neuroimaging techniques that reveal which regions of the brain are active when performing a particular task led to the serendipitous discovery of mind-wandering networks in the brain.

Researchers realised that when they told people lying in magnetic resonance imaging (MRI) scanners to 'rest' between tasks, a specific pattern of brain activity was detected.

"They realised that when individuals aren't engaged in a task, it doesn't mean that the brain is idle," says Irish.

The brain regions that spark up between tasks, or when there isn't much in the external environment to stimulate your senses, has become known as the default mode network. This is thought to be the network that operates when we daydream.

Drifting off task

But even when you are engaged in a task – reading a book, or completing a jigsaw puzzle, for example – your mind is prone to wandering.

How often this happens depends on how demanding or important the activity is, according to Klinger.

"The more demanding the task is – up to a point – the smaller the proportion of thoughts that would be considered task irrelevant," says Klinger, but "if things are very, very hard, and maybe beyond your capacity to deal with readily, then you may get an increase in the amount of daydreaming that's going on."

Quite often, you remain blissfully unaware your mind has even wandered away from the task at hand, says Klinger. Yet studies have shown that greater activity in the default mode network – presumably due to mind-wandering during a task – can make you slower to respond and more likely to make errors.

But you don't need an MRI to observe the effects of daydreaming. Daydreaming during an important task means you are less likely to fully comprehend material you read and can reduce how much information gets banked into our long-term memory.

"For the child at school who's trying to learn, if they're not being present and attentive, then the learning and committing to memory is going to suffer," says Irish.

Does everyone daydream?

Researchers have only recently begun to delve into whether people suffering from particular neurological conditions daydream more or less or differently to healthy people.

Irish's research looks at how activity in the default network changes in people with dementia.

"The default network connectivity is greatly reduced in neurodegenerative conditions like Alzheimer's," she explains. Whether this translates to a decrease in daydreaming is difficult to know for sure, says Irish, because people with dementia have difficulties reflecting on their mental state. But evidence suggests dementia impairs daydreaming.

"The ability of the dementia patient to mentally retreat from the current moment is highly compromised," says Irish. "They tend to stay very stuck on the task and they're not able to pull themselves away and let their mind wander off to different topics."

According to Irish, this has important implications for how we care for people with dementia and other neurological conditions.

"We know that patients with Alzheimer's disease respond very well to the provision of music as an external stimulation, or to old photographs and newspaper clippings," says Irish.

Daydreaming's darker side

But research suggests daydreaming also has a downside.

A 2010 study published in the prestigious journal Science found people were less happy when their mind was wandering. In the study, more than 2000 people had their daily activities interrupted by an app that asked them about whether they were daydreaming at that moment, and how they felt. People were less happy when daydreaming than when they were focused on the task at hand.

Other studies indicate a wandering mind is more common when our mood is low, and that it can enhance feelings of depression.

"There definitely is a darker side," concedes Irish; however, she believes what you daydream about is probably the most important factor in determining whether it is positive or negative. Ruminations about past events can be a feature of depressive thoughts, and fretting over future events can stoke the fires of anxiety.

But, as Klinger points out, "there are ways of training people to change the content of their thoughts". He cites a study from the 1980s where people prone to worry were instructed to spend a concentrated half hour each day worrying. This had the effect of reducing the amount that participants were spontaneously worrying at other times of the day.

It's also been found that people can be more likely to follow through on an action if they have daydreamed about it previously. As Klinger notes, this can have very negative outcomes if the person has nefarious intentions.

"It's pretty clear that people who engage in sexual violence – rape, for example – have a lot of fantasy content about that," he says. "It's also likely that with that kind of continuing rehearsal, that it becomes more likely that that person will carry out the action than if that person weren't engaging in that kind of daydreaming."

But this kind of negative consequence for daydreaming is extreme. For most of us, the cost of daydreaming is limited to the minor annoyance of not being able to focus on the current task.

The practice of mindfulness, which teaches people to attend to the here and now rather than allowing the mind to wander off, can reduce the off-task thought of mind-wandering and has been shown to be beneficial in the treatment of depression and anxiety.

For Irish, that doesn't mean that daydreaming can be jettisoned; it's just a matter of balance.

"Being attentive when you need to learn or commit something to memory, but then also finding ways to allow individuals to indulge in a spot of daydreaming and maybe harness that power in a way that allows them to express themselves creatively."

Published 06/05/2014