Secara biologis kebanyakan kadar hormon tetosterone lebih cepat merangsang pembesaran kelenjar prostat (BPH)
On 12/9/09, Remi <rsyaif...@yahoo.com> wrote: > > > > > `Testosterone's aggressive impact is a myth. It makes you friendlier' > Mark Henderson, Science Editor > 3 COMMENTS > RECOMMEND? > > It is popularly known as the selfish hormone, which courses through male > veins to promote egotistical and antisocial behaviour. Yet research has > suggested that testosterone's bad reputation is largely undeserved. > > Far from always increasing aggression and greed, the male hormone can > actually encourage decency and fair play, scientists have discovered. > > The common belief that it makes people quarrelsome, however, can cause it > to have that effect. When people think they have been given supplements of > the hormone they tend to act more aggressively, even though it does nothing > biological to promote such behaviour. > > The findings, from an Anglo-Swiss team, suggest that rather than > encouraging selfishness and risk-taking as a matter of course, testosterone > has subtler effects on human behaviour that depend very much on social > circumstances. > > RELATED LINKS > Christian Pfannberger banned from cycling for life > Caster Semenya and the middle sex > The research also highlights the importance of social expectations and > prejudices on the placebo effect: these can cause testosterone to influence > people's actions according to its reputation, rather than its biological > effect. > > "It appears that it is not testosterone itself that induces aggressiveness, > but rather the myth surrounding the hormone," said Michael Naef, of Royal > Holloway, University of London, an author of the study. > > "In a society where qualities and manners of behaviour are increasingly > traced to biological causes and thereby partly legitimated, this should make > us sit up and take notice." > > The popular belief that testosterone promotes aggression is founded in > animal research: castrated male rodents, for example, become less combative. > In humans, studies of male prisoners have found that those with higher > testosterone levels are more likely to have committed a violent crime, to > rebel against prison rules and get into fights. > > Some scientists, however, have questioned whether the male hormone > contributes directly to antisocial behaviour. The alternative view is that > testosterone makes people more anxious to seek high status. This can, in > different circumstances, promote either hostile or co-operative behaviour. > > The study, which is published in the journal Nature, sought to test this > using a common psychological exercise known as the ultimatum game. In this > game, a player is given a sum of money, say £10, to share with a second > player, offering as much or as little as he or she wants. > > If the offer is accepted, the pot is distributed that way, but if it is > refused, neither player gets any cash. Players who are very aggressive, > offering just £2 or £3, stand to benefit financially, but also risk coming > away with nothing. > > Before playing the game, a group of 60 women was given either a > testosterone supplement or a placebo. "We wanted to verify how the hormone > affects social behaviour," said Christoph Eisenegger, of the University of > Zurich. "If one were to believe the common opinion, we would expect subjects > who received testosterone to adopt aggressive, egocentric, and risky > strategies – regardless of the possibly negative consequences on the > negotiation process." > > The subjects who were given testosterone supplements in fact made much > fairer offers in the ultimatum game than those given a placebo, suggesting > that the hormone does not promote aggression in these circumstances, but > co-operation. > > "The preconception that testosterone only causes aggressive or egoistic > behaviour in humans is thus clearly refuted," Dr Eisenegger said. > > The only exception was when participants guessed that they had been given > testosterone and not the placebo. In these cases, they made more aggressive > offers. > > "Subjects who believed that they received testosterone — regardless of > whether they received it or not — behaved much more unfairly than those who > believed that they were treated with a placebo," the researchers wrote. The > results support the idea that testosterone promotes status-seeking, and that > this can encourage or discourage aggression depending on the circumstances. > In the ultimatum game, an unfair offer risks damaging a person's status and > reputation if it is rejected, so co-operative strategies are favoured. But > in situations of conflict, as in prisons, a more aggressive and risky > strategy may pay off. > > "In the socially complex human environment, pro-social behaviour secures > status, and not aggression," Dr Naef said. "The interplay between > testosterone and the socially differentiated environment of humans, and not > testosterone itself, probably causes fair or aggressive behaviour." > > http://www.timesonline.co.uk/tol/news/uk/health/article6949048.ece > > >
