In April 2007, we embarked on a study into the psychology behind charity collections. Was it possible, we wondered, to influence the amount donated to good causes by changing the appearance of the charity box?

We teamed up with Borders bookstores and conducted a week-long secret study across Britain. Participating stores were sent four charity boxes, identical in shape and size, all advertising the same charity - the National Literacy Trust. Each carried one of four messages: "Please give generously", "Every penny helps", "Every pound helps", and "You can make a difference".
The boxes were placed at randomly selected tills, and managers monitored the amount collected in each.

Would the subtle changes in message make a significant impact on whether people donated their cash to charity?

The answer was an irrefutable yes. The boxes contained vastly different amounts of money; "Every penny helps" came top, containing an impressive 62 per cent of all contributions, while "Every pound helps" trailed in fourth place with just seven per cent of the total take.

Why should such a small change have such a big impact? According to psychologist Robert Cialdini from Arizona State University, many people are concerned that putting a small amount of money into a box will make them look mean, so they avoid making any donation. "Every penny helps" legitimises even the smallest of contributions. In contrast, "Every pound helps" confirms people's fears that their donation will appear paltry so they give nothing at all.

We also varied the colour of the boxes, and discovered that red was by far the most effective, perhaps because it elicits a sense of urgency. I

nterestingly, large variations in giving also emerged between the regions. London customers were the most generous, donating over 20 times more than people in the store yielding the lowest return, Birmingham.

Taken together, the results show that charity boxes can become up to 200 per cent more effective by being painted red, labelled "Every penny counts", and placed outside Birmingham.