Psychologists have come up with a free app, which they claim can tell you when in the day your brain works best.

The Moo-Q app asks users about their state of mind, then records how well they perform across five sets of mental tests.

The information is used to show how your mood and brainpower changes over the course of a day, and even a week.

Makers Hungry Mind Labs were given funding to develop their iphone app last year.

The app allows you to participate in Hungry Mind Lab's ongoing research at Goldsmith University in London while giving you immediate feedback on your mood and cognitive performance.

Above, test results shown on the Hungry Mind Lab website (‘Positive affect’ refers to feeling positive emotions – enthusiasm, energy, confidence – and ‘negative affect’ means experiencing negative emotions like distress, anxiety and anger.)

The scientists say: "We want to know how mood influences our cognitive performance. It is possible that our brains work better when we are happy and relaxed and worse when we are upset and distressed. But the opposite may also be the case: being a little happy may make our brains work harder to overcome the situation and move on."

They say the results of their research could affect the way the modern workplace is set up.

At the moment the app is only available for iphone, but the makers say they will consider making an android version if the iphone version is successful.