We know that weather and light can affect our moods, but to what extent do they influence our behaviours, particularly when it comes to spending?

A new study published in the peer-reviewed journal PLOS ONE shows that luminance — the intensity of light — has a correlation with financial risk-taking.

Associate Professor Agnieszka Tymula, a neuroeconomist from the University of Sydney, said light does have an impact on people's monetary gambles.

"We found out that luminance did affect individuals' risk attitudes. On days with higher luminance levels, people were more risk averse," Associate Professor Tymula said.

The research involved 2,500 people and basically gave them a choice between a certain $5 payout or a lottery where they could win $20.

With that lottery, sometimes participants were told the probability of winning or not at all.

Associate Professor Tymula said the study found more light made people more careful about money, but they also had a greater tolerance for unknown risks.

"We asked people to choose between $5 for sure and a lottery. But in that lottery we wouldn't specify the odds of winning," Professor Tymula said.

"And those with higher luminance levels people acted as if they were more optimistic so they were more likely to go for the lottery.

"So when there was less light people were willing to take more risk, but they were more averse to ambiguous lotteries so they acted as if they were more pessimistic about the odds of winning, when the odds were not known."

So, how does this work?

The idea might sound far-fetched to some, but Associate Professor Agnieszka Tymula explained the science behind it.

She said the retinas in our eyes carry information, based on the light, to a part of our brain which regulates things like sleep, hunger, thirst and sex drive.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 3 minutes 9 seconds 3 m 9 s Could light affect how we determine financial risks? Download 5.8 MB

That is why, as previous studies have shown, our moods are often affected by the weather.

Shane Oliver, the chief economist at AMP Capital, said it could also explain unknown market fluctuations.

"It's quite conceivable that luminance or light is also having an effect on investors' decision making," Mr Oliver said.

But he was surprised by some of the study's results.

"The optimism correlates with risk aversion, rather than taking on more risk … and likewise when they feel more pessimistic they would more risk adverse," he said.

However, Mr Oliver thinks these findings could help consumers, marketers and investors and also help manage problematic financial risk-taking.

"If this finding is backed up by similar studies it could suggest that when casinos for example are given their licences, that they should be required to have plenty of light," Mr Oliver said.

"Because could lead to a situation where people are less inclined to take the gamble and more inclined to do things which offer a more certain bet."

