Big picture: Are prisoners calmer when their cells are pink?

On the back of research first published in the 1970s and 80s, an increasing number of jails in the Western world are painting their cells pink, in the belief that doing so has a calming effect on prisoners.

Unfortunately, this early research was poorly designed. But now a team of psychologists led by Oliver Genschow at Ghent University has provided the first carefully controlled systematic test of the pink cell claim. They trained guards to measure the aggressive behaviour of 59 male prisoners in Switzerland, who were placed into special detention as punishment for violating prison regulations. Half of them were randomly assigned to cells painted entirely pink, across the floor, walls and ceiling. The other half were placed in cells of identical size, but painted white, with a grey floor. Aggression ratings were taken on arrival in the cells and after three days.

The prisoners showed reduced aggression at the end of three days, compared with at their arrival, but crucially, at no time was there a difference in aggression levels (in terms of emotions or behaviour) between prisoners in the differently coloured cells. The same null result was found when analysis was restricted to just those prisoners who started off low in aggression, or just those who started off with higher aggression.

Genschow and his team said their results question the wisdom of painting prisoners' cells pink, although they admit that one reason for not finding an effect might be the sample size. 'Although 59 participants is quite a lot for such a field study, it might be too less to detect a small effect'. However, they speculate that placing prisoners in pink detention cells could even be counter-productive: 'It may attack inmates' perceived manhood and/or cause feelings of humiliation.'

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