Struggling with a difficult mental task? Zapping the brain region linked to our motivation to make a mental effort might help – for a while. People who had this part of their brain stimulated by electrical currents excelled at a difficult task, but also became more mentally fatigued afterwards.

“Their performance is much better; however, this good performance comes with lower motivation in the end,” says at the University of Munich, Germany.

Xia and her colleagues put electrodes on the heads of 31 volunteers with no known health conditions. During a half-hour session in an MRI scanner, the volunteers spent 20 minutes doing the 3-back memory test, where you have to remember and identify the third item back as an ongoing sequence is presented to you – a very demanding mental task. They were then offered €1 for doing an easy test or €2 for a harder one.

During the 3-back memory test, the electrodes delivered transcranial direct current stimulation (tDCS) to a region of the brain called the dorsolateral prefrontal cortex to randomly chosen volunteers, who were unaware they were receiving it.

Other studies have shown the dorsolateral prefrontal cortex is involved in we make. “Our dorsolateral prefrontal cortex helps us to work hard,” says Xia.

The volunteers who had tDCS reacted faster and more accurately than those who didn’t receive this stimulation. For instance, their average reaction time was 0.98 seconds, compared with 1.12 seconds with sham stimulation.

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Xia thinks stimulating the dorsolateral prefrontal cortex will boost brain performance generally. “I can imagine any cognitive task will be better, but afterwards you will feel more fatigued,” she says.

After the tests, the volunteers who got tDCS had higher levels of the neurotransmitter glutamate in their dorsolateral prefrontal cortex, according to a non-invasive technique called magnetic resonance spectroscopy. The higher their glutamate levels, the more likely they were to choose the €1 task over the €2 one.

Some researchers think mental fatigue is a result of the buildup of glutamate, which can harm cells at high levels. Xia thinks her team’s findings are the strongest evidence of this yet. The findings suggest it is important to take a break when you feel mentally tired, she says.

Xia thinks future studies should also look at the dorsolateral prefrontal cortex in people with conditions such as depression, which can affect motivation.

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“I think the claim that the stimulation made people ‘work harder’ is well substantiated,” says neuroscientist Emile Radyte at Samphire Neuroscience, a UK-based company exploring the use of tDCS to treat conditions such as premenstrual syndrome. But the study doesn’t prove that higher glutamate levels were the cause of the greater mental fatigue, she says.

Radyte says her trials have shown that if productivity is hindered by conditions such as premenstrual syndrome, applying tDCS over the dorsolateral prefrontal cortex can restore it. But she isn’t sure about using it to boost mental performance. “A 20-minute laboratory task does not establish a net productivity benefit over a working day,” says Radyte.

It is a good study, says at University College London, but the greater mental fatigue could be a result of using more neural energy, rather than the buildup of glutamate. It’s also hard to precisely target the dorsolateral prefrontal cortex with tDCS without an MRI scanner to guide you, says Lavie. “Drink coffee instead,” she says.

Adults are often thought to be less creative than children, as we swap painting for presentations and sandpits for spreadsheets. But in a new study, children actually performed worse on creativity tests than adults – yet made up for it in confidence.

“We found that adults are actually more creative thinkers,” says at the University of Graz in Austria. “But children enjoy creativity more and are much less worried about what others think about their ideas.”

There is a popular belief that children are more creative than adults, he says, which may come from children having more time and opportunities to engage in creative activities. Yet prior research suggests that .

These studies were often based on a single task, like imagining alternative uses for everyday objects, says Benedek. Taking a broader approach, he and his colleagues recruited 92 children (aged between 4 and 7) and 70 adults (aged 25, on average) to carry out three creative tasks.

First, they had to come up with as many alternative uses for a tin can as possible within 3 minutes. Then, they drew freely for 8 minutes, and in the final task, they had 8 minutes to draw an animal that doesn’t exist.

Five people who weren’t involved in the research were then trained to objectively judge creativity based on originality and whether the final result fulfilled the brief of the task.

In the first task, the adults scored 3.9 points, on average, out of 5, while the children scored 2.9 points. One of the adults imagined a tin can could be used as a “Halloween candy box when on (a) diet”, whereas some children imagined it as a rattle.

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In the second and third tasks, the adults scored 0.6 and 1.9 points higher, respectively, than the children.

The findings underscore how creativity draws on combining ideas from prior experience, says at King’s College London. For instance, adults are probably aware of more animals than children, so have a greater variety of creatures to draw from when producing a fantasy animal.

After completing the tasks, the participants were asked questions like “How well do you think you performed the task?”, “How much were you worried/anxious to not perform well on the task?” and “How much fun was the task?”.

The researchers found that the children were substantially more confident in what they produced, scoring their performances 4.8 and 4.6 points for the free drawing and animal tasks, respectively, compared with the adults’ 2.8 and 3.3 scoring.

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The children also reported lower anxiety compared with the adults. “If the purpose of creativity is to have enjoyment in it, to play and to be unfettered humans, then children are doing better at that,” says Ross.

But the two groups got a similar level of pleasure from the animal-drawing task. Adults may have liked that task’s specific instruction, which may have meant they worried less about being judged for their idea, says Benedek.

Regardless of the quality of the end result, people should try to be more creative for their wellbeing, says Ross. Engaging with the arts has been linked to reduced mental health problems and greater social skills. “Creativity, especially when done with other people, is really beneficial to your mental wellbeing – and you don’t have to score 5 out of 5 on a ranking scale,” she says.