BEHAVIOUR watchers have found a third type of person in addition to "givers" and "takers".

Following a computer game invented by psychologists in the United States and involving 84 university students, the third type was labelled "reciprocator".

Psychologists tested the willingness of volunteers to work together for mutual benefit and identified three distinct types of individual: co-operators, reciprocators and free-riders.

Co-operators were "givers" who seemed happy to contribute to the group despite a cost to themselves.

Free-riders were "takers" who put their own interests first and tried to avoid personal loss.

But the biggest group, 63% of those tested, were "reciprocators".

These people, who appear to make up the majority of the population, displayed a more complex behaviour pattern based on a "conditional strategy".

They became more prepared to incur personal cost for the good of the group as they realised they might win more back at the end of the day.