What Prevented the Game Theory Expert From Executing the Perfect Murder Plot?

Faking humanity is hard

Rafael Robb thought he was much smarter than everyone else. As an Ivy League economist specializing in game theory, a highly mathematical field, one could claim he had some reasons to believe in his intellectual superiority. In 2017, the website RePEc ranked him in the top five percent of economists in the world by looking at published research papers.

But his overconfidence may have misled him into thinking he just might get away with murdering his wife.

Philadelphia Magazine has a pretty revealing story. Reading it, one might start questioning how smart game theory experts really are. From the piece:

Robb developed a weak alibi and a bad burglary scene, which everyone — from the patrol cops up — recognized as staged. In fact, his “success” in killing his wife and emerging, years later, as a free man appears due mostly, if not entirely, to his good fortune in facing prosecutor Bruce Castor, a man who was eyeing a higher office…

“Weak alibi” refers to him standing in front of a store’s surveillance camera drinking soda for 10 minutes for no apparent reason—other than to provide himself an alibi. The list of goofy and not-so-smart things he did goes on. But you will have to read the whole piece to find that out (there is also this documentary on YouTube)—I will just point out some things that caught my attention.

Aside from intellectual hubris, I think the main thing preventing Robb from devising a “perfect” murder was his utter absence of emotions. Namely, it seems the guy was a psychopath. Being a psychopath means lacking empathy. And lacking empathy means that, in order to form social relationships, one has to learn by observation, trial and error, all of the things that other people would naturally “know”— simply due to having empathy.

In fact, he showed up at his wife’s funeral — the chief suspect milling among the mourners in a cardigan and slacks, not even wearing black. The puzzle pieces Ellen had left behind looked so obvious now, particularly in light of Robb’s behavior.

He jumped in among the pallbearers, grabbing a handle of his wife’s coffin with one hand while holding a cup of coffee in the other. During the wake, he broke down over her closed casket, tearlessly sobbing. “Oh, Ellen!” he shouted. “I can’t believe it! What will I do without you?”

Everyone stood and watched, remembers Kim Gregory, “because there was no emotion in his voice. It was like he understood what he was supposed to do, but he didn’t feel it.”

Now, no one teaches you that it is inappropriate to hold a wife’s coffin with one hand while holding a cup of coffee in the other. That’s not the type of knowledge you learn in school or something you learn by observation. But if you have empathy, you simply know it is inappropriate. You sense the tension between the acts.

That kind of “knowledge”—or intuition if you will— comes naturally to a person who has empathy, i.e. a normal emotional makeup.

On the other hand, one can easily learn that sobbing in front of other people is an “appropriate” behavior for a person expressing grief. You can see it in movies, read in novels, and so on.

The fact that one type of behavior is easily learned by observation whereas the other one is not, explains Robb’s contradictory behavior where at one moment he demonstrates behavior typical of a grieving person. In contrast, at another moment he leaves subtle signs of an untroubled person.

Perhaps there is even a lesson in that. To correctly evaluate the character of a person, one may be advised to attend more to those small and subtle acts that are more revealing of a person’s underlying traits rather than to grand gestures that may be learned through experience and thus are easily faked.

This brings me back to an earlier post where I discussed the importance of emotions in our everyday lives:

Decisions based on emotions are harder to revoke since emotions are stubborn. Decisions based on reasons are easier to revoke since reason is shifty; all you need to revoke a decision or a certain course of action is a better reason so the future seems more uncertain when reason is governing your affairs rather than emotions. Basing your decisions on cost-benefit analysis opens the door for revoking your decision if the cost-benefit ratio changes in the future.

Because being heavily reliant on emotions in your decisions and actions means you will be more motivated and persistent in attaining a certain goal, observers can use the apparent emotionality of your decisions and actions to gauge your level of commitment to attaining that goal.

Now, if your decision has an effect on me, then I might care whether your decisions are based more on reason or emotions. In romantic partnerships, the adaptive challenge for each side is to diminish the risk of being abandoned by the other side. That means the demand that the other side is entering the partnership based on emotions will be greater. A calculated, emotion-free, approach will be looked at with suspicion.

…

One important feature of emotions, one that makes us think of emotions as “stubborn”, is that they are resistant to argumentation and persuasion. But it is a feature, not a bug! Emotions tend to override the arguments and reasons and there are situations where it could be beneficial for us not to “follow the argument wherever it leads”, contrary to Socrates' advice.

The fact that a person’s decision to be romantically involved with another person is not solely dependent on reasons, but is more reliant on emotions, means it is harder to revoke it because the person is less open about being persuaded to revoke it.

People could observe this emotionality of actions and use it as a cue to assess one’s seriousness and reliability as a potential partner.

As Philadelphia Magazine’s story makes clear, Robb struggled with understanding the emotions of his wife’s brothers, attributing their motivation to greed. A case of typical mind fallacy, to be sure:

“They keep showing up,” he said, “going to the media, complaining about me. Why would they still be so angry? What’s in it for them? You would think they would move on with their lives. We should all move on with our lives.”

Robb even suggested that their efforts to keep him in jail were part of a more complicated plot. They did all that, he said, to build their eventual civil case — to pose as mourners. What they really wanted, all along, was money.

His assessment reveals why he and Ellen Gregory Robb were never a good match: She seems to have been motivated in life by the emotional things people value — love and family. He, on the other hand, seems to look at the world from a place outside all that, a vantage where normal human feelings are puzzling.

Do you ever think, I asked, that maybe the brothers just hate you? Because you killed their sister?

His answer rendered him transparent, recalling the motive police originally gave for charging him with first-degree murder. “Hmm!” he said in a high-pitched exhalation, and stared off into the distance. “That could be. They want to cause me pain. But what does that actually accomplish? It is the money. That is the motivation that makes the most sense to me.”

In Robb’s universe where all people are simply maximizing their utility (defined narrowly), the anger of the victim’s relatives simply has no point, other than to make money perhaps. The cost-benefit analysis suggests they should have stopped bothering him already. But apparently, they did not.

This illustrates that modeling the minds inside other people's brains as exactly the same as our own minds results in errors in the absence of sufficient similarity between the minds. Indeed, sufficient similarity among agents is a secret ingredient that makes the interaction of those agents run more smoothly.

But Robb's story also illustrates how fake humans, i.e. humans severely deficient in the normal range of emotions, are ultimately incapable of perfect acting, however smart they may be and however hard they may try.

The subtle signs that betray their fake humanity eventually leak out to the outside world.

Perfect emulation is hardly achievable since some—indeed many!— things can hardly be grasped solely through observation. The sheer quantity of observations required to attain mastery in imitating humanity exceeds the time and opportunities available to most individuals. In the end, you either have it or you don’t.