Participants in the studies were questioned about a range of qualities they look for in a mate, including examples of altruistic behaviour such as ‘donates blood regularly’ and ‘volunteered to help out in a local hospital’. Women placed significantly greater importance on altruistic traits in all three studies.
Yet both sexes may consider altruistic traits when choosing a partner. One hundred and seventy couples were asked to rate how much they preferred altruistic traits in a mate and report their own level of altruistic behaviour. The strength of preference in one partner was found to correlate with the extent of altruistic behaviour typically displayed in the other, suggesting that altruistic traits may well be a factor both men and women take into account when choosing a partner.
Dr Phillips said: “For many years the standard explanation for altruistic behaviour towards non-relatives has been based on reciprocity and reputation — a version of ‘you scratch my back and I’ll scratch yours’. I believe we need to look elsewhere to understand the roots of human altruism. The expansion of the human brain would have greatly increased the cost of raising children so it would have been important for our ancestors to choose mates both willing and able to be good, long-term parents. Displays of altruism could well have provided accurate clues to this and genes linked to altruism would have been favoured as a result.”
Dr Phillips concluded: “Sexual selection could well come to be seen as exerting a major influence on what made humans human.”
Dr Tom Reader in the School of Biology said: “Sexual preferences have enormous potential to shape the evolution of animal behaviour. Humans are clearly not an exception: sex may have a crucial role in explaining what are our most biologically interesting and unusual habits.”
— Ends —
Notes to Editors: The University of Nottingham is ranked in the UK's Top 10 and the World's Top 100 universities by the Shanghai Jiao Tong (SJTU) and Times Higher (THE) World University Rankings.
It provides innovative and top quality teaching, undertakes world-changing research, and attracts talented staff and students from 150 nations. Described by The Times as Britain's "only truly global university", it has invested continuously in award-winning campuses in the United Kingdom, China and Malaysia.
Twice since 2003 its research and teaching academics have won Nobel Prizes. The University has won the Queen's Award for Enterprise in both 2006 (International Trade) and 2007 (Innovation —School of Pharmacy).
Its students are much in demand from 'blue-chip' employers. Winners of Students in Free Enterprise for four years in succession, and current holder of UK Graduate of the Year, they are accomplished artists, scientists, engineers, entrepreneurs, innovators and fundraisers. Nottingham graduates consistently excel in business, the media, the arts and sport. Undergraduate and postgraduate degree completion rates are amongst the highest in the United Kingdom.