Impulsiveness can be measured in many ways. That chosen by Dr Nave and Dr Nadler was mathematical. In the largest experiment yet conducted on the effect of testosterone on human behaviour, which they have just reported in Psychological Science, they tested the hormone’s influence on volunteers’ capacity to do mental arithmetic. They conclude that, in this sphere at least, testosterone encourages men to jump to the wrong conclusions.
Three of the questions were designed in a way that might encourage an impulsive but incorrect reply. […] The others, which involved adding up as many sets of five two-digit numbers as possible within five minutes, simply required mental arithmetical skills to be applied accurately.
Participants who had not received the testosterone rub answered an average of 2.1 of the tricky questions correctly. Those who had been dosed with the hormone managed only 1.7.
Impulsive answers to mathematical questions are, admittedly, quite a specialised form of impulsiveness. But, having established the principle, Dr Nave and Dr Nadler hope to extend the scope of their research. They will use bigger groups and different tests. And they will also try the same experiments on women, to see if their powers of self-control, too, succumb to testosterone’s impulsive influence.