Just 3 days before Christmas, Olivia Robb, age 12, lost her mother in mysterious, gruesome way. Ellen Robb, of Upper Merion Township, PA, was found bludgeoned to death in her home on December 22, 2006. Ellen was just shy of 50 and a stay-at-home mom, married to Dr. Rafael Rob(b), a Professor of Economics at the University of Pennsylvania.
Dr. Robb (the final “b” is often dropped from his name), has obviously been the main subject of suspicion in his wife’s murder since the beginning. As I related in “The Mysterious Murder of Ellen Robb,” the memorial service for the former Ellen Gregory made this suspicion among her friends and family perfectly obvious.
Huff’s Crime Blog and CrimeBlog.US reader Melly left a comment on the preceding entry about this crime that really caught my attention.
With a quote from GameTheory.net, Melly introduced the idea of the “grim trigger.”
Game Theory (link goes to source page for information to follow) studies human behaviors, the way people interact in certain situations. Under the umbrella term, “Game Theory,” there is a diverse mix of disciplines like math, economics, sociology and psychology. If you are as terminally right-brained as I am, jumping the “math and economics” hurdle might allow you to see that this is one of the most fascinating fields of study out there.
There’s no good short explanation of Game Theory as a whole, so a Google query might help: “Game Theory.”
I examined the “Prisoner’s Dilemma” in the previous entry. Rafael Robb has co-authored a number of papers in his academic career that discussed some element of the Prisoner’s Dilemma in detail. From GameTheory.net, a good, concise definition of the Prisoner’s Dilemma:
A game frequently displayed in television police dramas. Two partners in crime are separated into separate rooms at the police station and given a similar deal. If one implicates the other, he may go free while the other receives a life in prison. If neither implicates the other, both are given moderate sentences, and if both implicate the other, the sentences for both are severe. Each player has a dominant strategy to implicate the other, and thus in equilibrium each receives a harsh punishment, but both would be better off if each remained silent. In a repeated or iterated prisoner’s dilemma, cooperation may be sustained through trigger strategies such as tit for tat.
I mentioned the Prisoner’s Dilemma in the previous entry because I felt that a man with Dr. Robb’s knowledge of Game Theory would know better than to do one thing, if he wanted his wife dead — he would know better than to get an accomplice. The usual outcome of the Prisoner’s Dilemma would dictate that both he and that accomplice would end up on the hook for the crime.
There are typical trigger strategies sometimes used by the players in a game of Prisoner’s Dilemma. This becomes relevant if you broaden your conception of what a typical playing field for this game might be. One trigger strategy is “tit for tat.” This is a strategy used in multi-period game play wherein player X responds to a player Y’s strategy in one period of play by repeating it themselves in the next period of game play.
If marriage itself is a cooperative strategy where two players are locked in a game against the world and sometimes one another, then it could be that domestic violence is sometimes an example of the Grim Trigger Strategy coming into play.
From CBS/AP, an article published December 29, 2006:
[Rafael] Robb is an expert in “game theory” and teaches at Penn’s School of Arts and Sciences. Genovese said his client had cooperated with police, including granting police consent to search the family’s two cars and Robb’s office at Penn. “He’s confident that the police will find the person who did this and bring them to justice,” Genovese told the Philadelphia Inquirer.
Though estranged, the couple lived together in the home with their 12-year-old daughter. Authorities are looking into reports that Ellen Robb had initiated divorce proceedings…
Emphasis mine. From the definition of the Grim Trigger Strategy:
… Grim trigger is a severe trigger strategy since a single defection brings about an eternal end to cooperation, in contrast to the much more forgiving tit for tat.
For at least a decade, the Robbs lived together, though they were “estranged.” This meant that they had an ongoing cooperation throughout the period, perhaps geared towards raising their daughter, Olivia.
But recently, Ellen Gregory Robb had decided it was time to end the whole charade. She didn’t have a job, apparently, and her work history (mentioned in this Philadelphia Daily News article), never indicated a high-dollar earning potential, yet she apparently felt it was time to, in game play terms, “defect.”
Did Rafael Robb then decide that it was actually his place to put (as Melly noted) “an eternal end” to their cooperation?
Surely it couldn’t be that simple, laid out there in the structure of Game Theory.
Yet this was a big part of the man’s life, and no doubt of his thinking.
How fair is it to Dr. Robb to even speculate that he murdered the mother of his daughter?
Read this comment left on the previous entry by “CN.” “CN” writes as if he/she is familiar with the neighborhood where the Robbs live, where Ellen was murdered:
This is an extremely quiet and safe neighborhood, and everyone is shocked and very tense about this, wanting some answers. However, Prof. Robb seems very calm and non-chalant over the whole thing. He has returned to the home and has been staying there, not easy for someone who cared at all for the fact that the mother of their child was brutally murdered in that house. Additionally, since returning the house has been left open, the garage door was up all night the other evening, and the outside lights (always on all evening while Ellen was alive) were all shut off. I know that if I came home to find a family member murdered I would be terrified to be in that house, and if I really thought it was a stranger I’d have my house locked up like a drum with every light on…
If “CN” had left no identifying info with his/her post, I would have viewed the statement with more skepticism than usual, but the fact is, “CN” posted his/her real name in a field only viewed by me, not seen by the public. Not perfect verification, but enough to render “CN’s” comment interesting.
Could it be that Robb’s so-called “suspicious behavior” is the product of a self-contained and unemotional personality, a cool, left-brain oriented mind? Possibly. Whatever he is, it is highly unlikely that Professor Robb is even remotely approaching the conventional definition of the word, “stupid.”
Then again, the real world rarely reduces neatly to a set of equations, and it never conforms to the “rules” of game play. Not where the messiness of human unpredictability comes into consideration.
That’s why certain murders are sometimes called “crimes of passion.”
That might be the question in the murder of Ellen Gregory Robb — was it a crime of passion, or, more chilling, a crime of dispassion, born out of one man’s calculations of risk and benefit?
The sheer strangeness of this case is that either one could point directly at the man who first made that call on the afternoon of the 22nd to police — Dr. Rafael Robb.
I heard yesterday from Philadelphia radio personality Susanne LaFrankie. She may have me on to talk about this case — not sure. But it was very nice to know that a journalist like Ms. LaFrankie is reading.
UPDATE, 1/03/07, 5:22 p.m. ET
In this post at Websleuths.com, “Winteryns” links sleuthers to an article declaring that Rafael Rob is now officially a suspect in his wife’s murder. A quote from the article, titled “Penn Professor Named Suspect in Wife’s Murder”:
Circumstantial evidence “very strongly” indicates Rafael Robb may have had a role in the slaying of his 49-year-old wife, Ellen, Montgomery County District Attorney Bruce Castor said at a news conference.
“Everything I have seen points in the direction of Dr. Robb,” Castor said…
Another poster in the thread gave themselves the screen name “hedidit.” This post left by “hedidit” today is interesting: “I know them both. Trust me, he did it!”
Later, the same person wrote, “… HE is the frugal one beyond belief. And extremely controlling. So, you’ve guessed correctly on some things…”
But “hedidit” said they could not make more statements online because they’d given statements to authorities.
What they did post was enough for me. And not much of a surprise. A man who might have killed his wife being controlling? Parsimonious? Sadly, not surprising at all.
UPDATE, 1/05/07, 8:34 p.m. ET
Things are not going well for Rafael Robb. From ABC and the AP:
Rafael Robb remains a full, tenured professor at Penn, but under a mutual agreement, another professor will take over the graduate seminar Robb was scheduled to teach on game theory, university spokeswoman Lori Doyle said…
He is, after all, now officially a suspect in his wife’s brutal, bloody murder.
As an aside, I wanted to thank Susanne LaFrankie for having me guest on her drive-time show on radio station WPHT last night. I enjoyed speaking with her and hope I made some sense, if you happened to be listening there in Philadelphia.
