Steven Pinker -- How the Mind Works - Hampshire High Italian ...

436 | HOW THE MIND WORKSAmazon rainforest whom he has studied for thirty years. He showed howkinship is the cement that keeps villages together. Close kin fight eachother less often and come to each other's aid in fights more often. A villagefissions when its population grows, the villagers become less relatedto one another, and they increasingly get on each other's nerves. A fighterupts, loyalties divide along blood lines, and one party storms off withhis closer kin to form a new village.A spouse is the most familiar example of fictive kin: genetically unrelatedpeople who are called kin and claim the emotions ordinarilydirected at kin. The biologist Richard Alexander has pointed out that ifspouses are faithful, if each acts on behalf of the union's children ratherthan other blood relatives, and if the marriage lasts the lifetime of both,the genetic interests of a couple are identical. Their genes are tied up inthe same package, their children, and what is good for one spouse isgood for the other. Under these idealized conditions, marital love shouldbe stronger than any other kind.In reality, people's blood kin do claim some of their loyalties, and noone can ever be certain that a spouse is one hundred percent faithful,much less that the spouse will never desert or die. In a simplemindedspecies, the strength of spousal love might be set at some optimummedium level reflecting the overall probability of nepotism, infidelity,desertion, and widowhood. But humans are sensitive to the particulars oftheir marriages and fine-tune their emotions accordingly. It is no surpriseto a biologist that in-laws, infidelity, and stepchildren are the majorcauses of marital strife.Because a couple's genes are in the same boat, and each spouseshares genes with his or her kin, the kin have an interest—in both sensesof the word—in their marriage. If your son marries my daughter, ourgenetic fortunes are partly linked in our common grandchildren, and tothat extent what is good for you is good for me. Marriages make in-lawsinto natural allies, and that is one reason why in all cultures marriagesare alliances between clans, not just between spouses. The other reasonis that when parents have power over their adult children, as they had inall cultures until recently, the children are excellent trade goods. Sincemy children don't want to marry each other, you have something il need: