Decision to make – check the weather forecast!

With most people leading increasingly urban and indoor lives, you might suppose that weather is only relevant to decisions about outdoor activities such as sports, gardening, hill walking, going to the beach etc. Except for catastrophic events such as hurricanes, surely weather conditions have nothing to do with decision making in general.  Not so according to a two year study of the effect of sunlight on decision making.

The researchers say they followed on from previous findings which had established that the neurobiological pathways involved in regulating our preferences are affected by light. They set out to investigate the impact of light exposure on decision making factors such as attitude to risk, ambiguity and consistency of choice.

How light affects your moods

Light therapy is well recognised as effective in helping people who suffer from SAD over winter. But light levels affect all of us in profound but less obvious ways on a daily and seasonal basis. The amount of light we experience is picked up by a dedicated light sensor in the eye. This transmits light to the hypothalamus which regulates hormones and neurotransmitters governing a range of bodily functions. Besides basics such as body temperature, sleep, and hunger the hypothalamus also influences our moods and attitudes.

More ‘risky’ choices

The researchers decided to test how light exposure would affect decision making under risk. They confirmed their hypothesis that relatively higher exposure to light leads to more optimistic beliefs and therefore more ambiguity tolerance.

It wasn’t the absolute level of light, but how much this had increased compared to the previous two days that affected people’s tolerance of ambiguity, increased inconsistency and tendency towards more risky less ‘rational’ choices.

The researchers present their findings with caution “the observed effects are far from dramatic”, and changing light levels “don’t fundamentally change how we behave and what we like”. But they do claim, “without doubt weather affects individual behaviour”. Interestingly they also speculate that this individual effect could cumulatively be very significant. For example manipulating the overhead light intensity in stock markets could have quite an impact on volatility!

Shinning light on your decisions

It’s quite natural to feel buoyed up when the sun shines brightly after a few dull days. But next time you have an important decision to make that involves a significant risk would you want to save it for a rainy day, or let the sunshine illuminate your best choice?