WOMEN have evolved to pursue affairs in case they decide to leave their partners, scientists have suggested.
While men have similar programming, it seems that the trait is more prevalent in females.
The new research challenges the assumption that humans are meant to be monogamous and that breaking up with somebody is a sign of failure.
The “mate-switching hypothesis” suggests that humans have evolved to test their own relationships – and constantly check for better long-term options.
Scientists claim that this theory applies particularly to childless women – whose choice of partner can have a huge impact on any children they may have.
David Buss, Cari Goetz and colleagues, said in a research paper: “Lifelong monogamy does not characterise the primary mating pattern of humans. Breaking up with one partner and re-mating with another — mate switching — may more accurately characterise the common, perhaps the primary, mating strategy of humans.”
For early humans, when few lived beyond the age of 30, experimenting when it came to partners may have been the key to survival.
The researchers argue: “Although break-ups are often moralised as ‘failures’, we propose that selection has sculpted a complex psychology designed to jettison current mates and acquire new ones in circumstances when mate switching would have been evolutionarily advantageous.”
Surprisingly, the paper even cites the actress Jennifer Love Hewitt, whose character in the television series The Client List said: “Husbands are like pancakes: there’s no shame in throwing the first one out.”
Their theory is also reminiscent of the tangled web of affairs featured in the 2004 film Closer, starring Natalie Portman, Clive Owen, Jude Law and Julia Roberts.
However, the ideas are proving controversial among those researching the evolution of human behaviour.
Until now the main explanation for the evolution of female infidelity was the “good genes” theory – that women are attracted to ‘less dominant’ men because they are more likely to stay with them.
Nevertheless, many women seek more masculine ‘affair’ partners — especially in their fertile period.
In evolutionary terms, this means that thy go for the “fittest” genes for their baby from the affair partner, to then have the child cared for by a more reliable long-term partner.
While this may sound devious, women’s real behaviour is more subtle.
David Buss, professor of evolutionary psychology at the University of Texas, and Goetz, assistant professor of psychology at California State University, San Bernardino, suggest that women keep track of their partner’s “mate value” – comparing it with that of single men.
They also evaluate “relationship load” — the costs imposed by partners who behave badly or fail to provide for them.
The scientists say: “Affairs serve as a form of mate insurance, keeping a backup mate should a switch become warranted in the future.”
The academics even suggest that women in positive relationships could benefit from affairs, adding: “A regular mate may cheat, defect, die, or decline in mate value. Ancestral women lacking a backup mate would have suffered a lapse in protection, and resources.”