Tools for Changing the World

Colour is important. In most parts of the world, specific colours have specific associations, and most of us have colour preferences, if not favourites and abhorrences (don’t get me started about orange).

So, you’d think there would be a lot of psychology research on how colours affect us and we’d have a good sense by now of which colours are associated with different effects.

You’d be half right. There has been a lot of research. Unfortunately, most of it contradicts itself.

For example, one study found that light in certain colours affected our blood pressure, breathing rate and pulse; another found no such thing. One study found that mail surveys printed on purple paper were more likely to be returned; two others done later found surveys of any colour to be equally likely to be sent back.

I find this almost as frustrating as I find interior decorators with a penchant for orange.

Fortunately, there are a few studies whose results don’t seem to have been countered, at least so far. Here are the highlights.

The colour red appears to lower creativity and puzzle-solving ability compared to green or black. In a series of experiments, Andrew Elliot and his colleagues found that exposure to red (even in the form of just a few numbers written in a red pen, or a square of colour on a title page) led study participants to do significantly worse on puzzles and IQ tests. This may have been due to anxiety or avoidance; study participants exposed to red also chose easier test questions when given a choice.

But red isn’t always negative. In a study I described previously, Richard Wiseman had bookstores put donation boxes for the National Literacy Trust at randomly chosen cash registers. Boxes with different messages attracted different levels of donation, but red boxes were also found to be more effective at generating contributions than boxes of other colours.

In a recent study, Ravi Mehta and Rui Zhu found that people looking at a red computer background were better at detail-oriented tasks such as memorizing and proofreading compared with people looking at a blue background. Those looking at a blue background turned out to be better at creative tasks.

Mehta and Zhu also found that against a red background, an advertisement was more persuasive if it focused on product details rather than showing images more loosely associated with the product. Against a blue background, the reverse was true.

In another experiment, they showed that descriptions of products that highlighted positive features (such as teeth whitening for toothpaste) were more persuasive against a blue background than a red or neutral one. However, descriptions that focused on avoiding unwanted outcomes (such as preventing cavities) were more persuasive against a red background.

So, it appears that if your message appeals to your audience’s creative side (“Help us find new solutions!”) or ability to make connections (“What do sunny beaches and birthday parties have to do with cameras?”), use blue in your presentation. If your message is prevention-based (“Wear your seatbelt!”) or detail-focused (“Nine vital features of this pencil sharpener!”) or is written on a donation box, use red.

This ought to mean that to appeal to both sides of your audience you should use purple, but I don’t recommend it. Instead, save purple for when you want to appeal to me. I like purple. And only partly because it isn’t orange.