Very excited with the temporary installation of our new spectral lighting system at Leeds University. Whereas most coloured lights are based on RGB, we have a system that has a lot of spectral control (it works by having 11 different coloured LED primaries). We have several PhD students who are using these lights with their research. Nic and Yiting are looking at the effect of light and colour on alertness and also on impulsivity. Meanwhile, Soojin (pictured) is looking at the effect of colour on creativity (though in her study we won’t be using really saturated colours like those shown in the pictures). Hoping for some great publications on this soon. However, if you are interested in whether coloured lighting can affect heart rate and blood pressure take a look at our AIC publication (pdf) that we presented in Tokyo in 2015.
Staff at a primary school in Dundee want to change the colour of the uniform because they think the red colour could affect children’s behaviour. According to the Headmistress Gillian Knox:
‘Red is often used to energise body and mind, and some research indicates that it can increase heart and breathing rates. [This is] not the calm, relaxed learning state we hope to achieve. A recent study linked red to impaired performance on achievement tasks.’
Pupils currently wear a bright red jumper or cardigan with grey trousers or skirt. But teachers want there to be only ‘small amounts’ of red – such as in the school tie.
However, although statements such as this – that red raises heart rates – are all over the red and often cited as facts (as in ‘everybody knows’) in fact there is very little evidence that looking at red can affect heart rates. We ran a study at University of Leeds last year and found no statistically significant effect of the colour of light on subjects’ heart rates or on their blood pressure. A review of the literature reveals little evidence: there is a PhD thesis from California from about 1950 that nobody can get hold off and a study with mentally handicapped children in the 80s. That’s it. Light certainly affects us physiologically but it is far from fact that red raises blood pressure.
It seems that only recently companies are carrying out what is known as split testing or A/B testing. Put two designs of a web site out and see which does best. Recently one company did just that. They had one web site with a green call-to-action button (as shown above) and another with a yellow call-to-action button. Changing the call-to-action button from green to yellow resulted in a 187.4% increase in conversions to their website. Is there some effect that yellow light could have compared to green? For example, could yellow light make users more impulsive?
According to Erika Dickstein it may be nothing to do with yellow at all but simply to do with the contrast – the yellow stands out better and therefore is more noticeable. Certainly more research is needed in this area.
According to a study this month people distrust cyclists who wear yellow. This is not the case for other sports such as motocross and sprint running – just cycling.
The study was carried out by French psychologists Yves Chantal and Iouri Bernache-Assollant.