[New Scientist reports...]
HOW much pain would you put up with to help your friend? Less than you would for your close relatives, but more than you would for a charity, according to a study that looked at the basis of altruistic behaviour. For women, however, best friends rank higher than cousins, while men put all family members ahead of friends.
Psychologist Elainie Madsen of the University of St Andrews, UK, and colleagues asked 137 participants from various cultural backgrounds to inflict pain on themselves in return for a reward given to a specified person or charity. Subjects were required to squat against a wall in a sitting position, which caused pain in the thigh muscles. The longer they chose to hold the position the greater the pain, but the bigger the reward for the beneficiary. The more closely related the beneficiary was to the participant, the longer he or she held the position. Charities, however worthy, inspired the smallest sacrifice (British Journal of Psychology, vol 98, p 339).
There's an intriguing gender difference. Women tended to spread their efforts more equally among relatives than men did, as well as putting up with more pain for best friends than for cousins. This could be down to the fact that in many societies women tend to move away from their families. "Women have to get along with everybody - including their mothers-in-law," says Phyllis Lee of the University of Stirling, UK.
The other possibility, says co-author Robin Dunbar of the University of Liverpool, UK, "is that females are just more social".