(Shown: not actual study participants)
The results showed that people would sacrifice an average of 20p per shock to prevent shocks to themselves and 40p per shock to prevent shocks to others. For example, they would pay on average £8 to prevent 20 shocks to others but only £4 to spare themselves 20 shocks.
Similarly, people would need an average 30p incentive per shock to increase shocks to themselves and 50p per shock to increase shocks to others. This means they would need a £10 incentive to give others 20 shocks but would do the same to themselves for £6.
Stannous Flouride's Book of Truthiness 