A scientist has thrown light on how testosterone affects an individual's behavior in a ''pro-social'' situation, an environment where it is advantageous for a person to assist someone else.

In an assessment for Faculty of 1000, Robert Sapolsky highlights a research on testosterone issued in Nature.

In an ''Ultimatum Game'', a ''suggester'' is given authority to make a decision how a sum of money is divided between him/herself and another player, ''the decider''.

The decider can either take on the proposal, and possibly receive less than a reasonable share, or refuse it, in which case both players get nothing.

All partakers in the game were women.

Women who were given testosterone unwittingly made more reasonable offers as compared to women who had a placebo.

Interestingly, females who thought that testosterone has anti-social, aggression-causing effects and who believed they'd received testosterone made offers, which were less fair, even when they had received a placebo.

When given to the subject in a blind test, testosterone can persuade pro-social plus anti-social behaviour.

But, as the researchers noted, "biology seems to exert less control over human behavior [than in other animals]," since awareness of having received testosterone drastically altered behavior.

As Sapolsky said, "Despite the seeming power of the proposer, the decider ultimately has the most power, and the proposer seriously loses status if the decider rejects their offer." (With Input from Agencies)