Standing by the 'Craiglist Killer'

It may be impossible to ever probe the mind of Philip Markoff, the alleged "Craigslist killer" arrested April 20 and charged with the murder of a young woman he allegedly met online. (Markoff has pleaded not guilty.) But what's up with his fiancée, Megan McAllister? On Thursday, her attorney said that she was calling off their wedding. But the bigger question is, what took her so long? After Markoff's arrest, the 25-year-old McAllister might have been expected to walk away immediately—or at least to keep quiet. Instead, she publicly reaffirmed her love and commitment to Markoff.

Psychologists offer considerable insight into this sort of inexplicable loyalty, much of it from studies unrelated to either love or murder. Here are just a few of the known cognitive mechanisms that might be at work when a woman makes the seemingly irrational decision to stand by her man:

The status-quo bias. The human brain is full of ancient cognitive tendencies, "biases" that were once highly adaptive but no longer are. One of these is a powerful preference for keeping things the same—a deep-wired resistance to change. In the earliest days of human evolution, indecisiveness could be perilous, even deadly, so commitment became deeply embedded as a mental strategy for life. The old bromide "Don't change horses in midstream" no doubt derived from this aversion to switching course. Such ancient biases become even more potent when the mind is under stress, as McAllister's certainly is now.

The endowment effect. This is a version of the status-quo bias, but it is focused on how we irrationally value possessions. Indeed, this cognitive quirk was first identified by behavioral economists, to explain why we don't handle our money in predictable and rational ways. Psychologists Ziv Caroman and Dan Ariely demonstrated this in a clever experiment some years ago. They studied Duke University students who were in a raffle for highly prized basketball tickets, comparing those who had won tickets to those who had not won. Posing as ticket scalpers, they asked the losers how much they would be willing to pay for a ticket. The average was $170. Then they asked the winners how much they would sell their ticket for. The answer was a whopping $2,400. In other words, the ticket owners dramatically overvalued the tickets simply because they already had them, and when asked, they invented a lot on nonrational, emotional reasons for not wanting to sell. This concept has since been broadened beyond personal finances to mean that we all inflate the value of what's in our grasp, in many of life's arenas—including relationships.

Cognitive dissonance. This well-documented phenomenon may help explain irrational decisions and judgments. The human mind basically finds it intolerable to live with much internal conflict. If we believe one thing and act in a way that betrays that belief, something's got to give: we must change either our beliefs or our actions. So the romantic partner of a criminal might not be able to reconcile her deep love for him with the possibility that he is guilty of heinous crimes. She might have a lot invested in the relationship, but if more evidence builds against her partner, she may find herself resolving her inner turmoil by finally moving on.

Loss aversion. This also goes back to our evolutionary roots, when losing was much worse than a bad night at poker. Losing was life-threatening, and as a result we still carry in our neurons a primitive fear of any loss, big or small. Psychologists have studied this aversion every which way, and invariably people will sacrifice the chance of a windfall in order to avoid any possibility of loss. McAllister is facing a huge loss—the end of her dreams, symbolized by her canceled summer wedding plans. So it's not surprising that she clung to her fiancee's innocence.

It's not all bad psychological news for McAllister. The human mind may be irrational and almost delusional at times, but it is also very protective. Right now she might be finding it impossible to imagine ever recovering, but psychological science shows that humans are terrible emotional forecasters. The fact is bad events never make us as unhappy as we think they will. Emotional equilibrium almost always returns, given some time.

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