Gifts and our genes

Ah the wedding… that rite-of-passage filled with rituals and traditions, not to mention the festival of consumption that manifests itself through the wedding breakfast, reception and of course the honeymoon. Don’t you just love a good wedding?

Well, unless you’re the one picking up the tab, of course, in which case it can all turn into one huge financial nightmare. And then there’s the gift to the happy couple, a potential minefield for any guest. What do you buy for the couple that has everything or that you maybe don’t even particularly like?

All of these aspects make the increasingly not-so-humble wedding day ripe territory for consumer researchers of all persuasions and evolutionary consumer psychologists are no exception. There are a whole host of wedding rituals steeped in neo-Darwinism, from the lavish signalling of status by the proud father-of-the-bride to the within-sex competition that can raise unfortunate tensions when selecting the bridesmaids’ dresses relative to the bride herself.

A recent paper by Sigal Tifferet and his colleagues explores one particularly interesting neo-Darwinian theme; the issue of gift-giving and genetic relatedness. According to evolutionary psychologists, kin altruism is a crucial determinant of gift expenditure. Put simply, we spend more on a gift the closer the recipient is to us in terms of genetic composition. A parent will spend more on a gift for their offspring, for instance, than a grandparent, uncle or distant cousin. And the expenditure declines relative to genetic lineage, with non-relatives buying the more frugal gifts more from a sense of social pressure than the fact they may just by chance be related if we go way way back.

In an interesting analysis of over thirty weddings, Tifferet et al found exactly these patterns evident in the wedding gifts received, both purchased and monetary. The closer the genetic relationship to the happy couple, the more generous the giver would be. Intriguingly, the researchers also found a difference between maternal and paternal lineage, relatives on the mother’s side of the family being more generous than the father’s, even where the actual genetic make-up would have been identical. This is probably due to differences in paternity certainty – a woman always knows she is the mother of the child she is carrying, but the man can never be 100% sure that he is the father.

Oh yes, weddings can be a minefield… in more ways that one!