Study in Europe

Men are instinctively greedy and having an unfair advantage over other men actually makes them feel good, according to findings by a team of scientists in Germany.

Whereas women feel a bit guilty if they are paid more than a co- worker, men gleefully gloat over getting more money than the other guys in the office.

It is all part of a primeval reward-incentive programme which is hard-wired into the male brain aimed at causing men to "go for the gold" and win out over other male competitors, the researchers said.

They performed brain scans which revealed that being unfairly paid more than a co-worker stimulates the "reward centre" in the male brain - making him feel like a winner and making him feel happy and content.

The reward centre evolved to provide feelings of pleasure in response to certain experiences.

It is activated when eating delicious food, having sex, or achieving a sought-after goal, but is also involved in drug addiction.

The new research showed, as expected, that payment for success in carrying out a task stimulates this part of the brain.

But, in men at least, the effect depends critically on how much a person earns compared with others.

If he is unfairly favoured, reward centre activation is much greater.

In the study, pairs of male volunteers were asked to undergo simultaneous brain scans while carrying out the same task.

Both participants were asked to estimate the number of dots appearing on a screen.

Providing the right answer earned a real financial reward of between 50 and 150 dollars. Each of the 38 participants were told how their partners had performed and how much they were paid.

The magnetic resonance scans monitored changes in blood circulation in the brain. High blood flows indicated the areas where nerve cells were especially active.

One area, the ventral striatum, lit up when volunteers earned money, but showed far more activity if a player received more than his partner.

A wrong answer, and no payment, resulted in a reduction in blood flow.

If both partners estimated the number of dots correctly but were paid different amounts, they also showed unequal levels of ventral striatum activity.

The player paid the higher sum showed a surge, while activity in his partner was dampened, despite getting the answer right. "This showed that stimulation of the reward centre was not merely linked to success.

Reporting the findings in the journal Science, Professor Armin Falk from the University of Bonn in Germany said: "This result clearly contradicts traditional economic theory.

"The theory assumes that the only important factor is the absolute size of the reward. The comparison with other people's rewards shouldn't really play any role in economic motivation," he said.

Having shown that competition counts for men, the researchers now want to conduct the same study on women.

Tests with Asian subjects are also planned to see whether competitive thinking is influenced by culture.

DPA