A Curious Miscellany of Items Philosophical, Historical, and Literary

Manus haec inimica tyrannis.

Tuesday, April 3, 2018

Pseudoscience and Serial Killing

We now know that, for many years, there was a serial killer operating in Toronto, preying on men in an area locally known as the “gay village”. The perpetrator has, it seems, now been caught. There is much debate on whether or not the police conducted a competent investigation, or whether the killer could have been caught earlier had Toronto’s finest taken the killings seriously. I will not enter that debate.

Instead, I’d like to comment on a rather sensational Toronto Star article headlined “Ph.D candidate profiled potential serial killer in gay village in July 2016”. In reality, it is the story of pseudoscience and a poor grasp of logic on the part of many practitioners of the journalist’s “profession”.

Sasha Reid is a University of Toronto PhD candidate. The article seems to imply that she has been a PhD candidate for 11 years, but that can’t be right. In any case, as a sort of side project to take her mind off her primary doctoral research (she studies serial murder), she has built a database of over 8,000 missing persons in Canada. The data she collected seemed to point to connections between some missing persons cases in the gay village. She profiled the suspected killer and brought it to police in July 2017. They seem to have done little with it, and probably for good reason, as we’ll see.

According to the article, the killer Reid profiled would possess the following seven characteristics, which we might treat as predictions

       1. Man.
       2. Blue collar job.
       3. “Somebody with a history of violence, at least a criminal record.”
       4. No college or university degree.
       5. “They’d be burying the bodies outside or somewhere in the home, like in their home, where they have access to it”.
       6. A little over 30.
       7. Person of colour.

The Toronto Star article tried to spin this story to portray Ms. Reid as a neglected genius who got it all right, if only the police had listened. This narrative is consistent with that newspaper’s overall critical attitude toward the way police conducted their investigation. As I said, I am not informed enough to judge — though I am tempted to grant a certain amount of deference to detectives, who after all know much more about such matters than do armchair critics like me. My point, as I hope to show, is that Ms. Reid is no such genius, and she got much less right than the article implies.

Let us take Reid’s predictions in turn.

Regarding prediction #1, that the killer is a man, I am unimpressed. There was, a priori, a roughly 50/50 chance of getting that one right whatever she guessed. (Perhaps there is a hermaphroditic serial killer somewhere in Toronto, but I’ll wager not.) The chance that the culprit is a man increases dramatically when that probability is conditionalized to reflect the fact that around 85% of known serial killers are male.

Regarding #2 and #4, given the common Hollywood portrayal of serial killers as highly cerebral and intelligent (think Hannibal Lector), Reid’s guesses here seem fairly prescient and informative. However, fictional ones aside, most serial killers are not particularly well-educated, nor are they generally high achievers. Even Ted Bundy, often given as a counter-example to this trend, although technically well-educated, was academically rather underwhelming: he acquired a bachelor’s degree after some seven years or so of study, and barely got into law school with a mediocre LSAT score (he eventually dropped out). The average IQ of a serial killer is just that – average. John Wayne Gacy was a contractor, Jeffrey Dahmer worked in a chocolate factory, and Willy Pickton was ostensibly a pig farmer. With these facts in mind,  #2 and #4 fall rather short of clairvoyance. In the present case, it turns out the actual killer is a landscaper who was hiding bodies in planters. He has no post-secondary education.

Technically, #3 is a tautology. Someone who has killed only once is not a serial killer. He is simply a killer, of the non-serial variety. Accepting the usual definition of a serial killer as someone who has killed three or more people, then by the time a killer earns the “serial” modifier, he must by definition “have a history of violence”. QED. Again, this “prediction” is not very illuminating.

Regarding #5, I’m not sure I even understand what Reid’s words mean. However, I will note the following: First, if I am to bury someone, I must necessarily do so either outside or inside. And if I am to bury someone inside, again, it must necessarily be in a space I have access to; I cannot bury a body using telekinesis. It could be my home, or it could be “like” my home, in the sense that, like my home, I have access to it.

#6 and #7 are important predictions, perhaps the most important of the seven (along with #1, though again, serial killers are almost always men, so that prediction is trivial). If you had to canvass the neighbourhood for witnesses who might have seen the criminal in question, physical characteristics such as age, sex, and race are crucial in identification. Imagine showing a potential witness a police sketch of a black man and asking them if they saw this person at such-and-such a place and time. If the suspect is actually white and a woman, you simply will not catch her on the basis of the sketch. If police are told to look for a black man under 30, and the suspect is actually white and over 65 years old, they will have been led quite far off the scent. They would fail to identify the real culprit as a viable suspect if they were to blindly follow this description.

Unfortunately for Ms. Reid, far off the scent is precisely where she would have led police, had they listened to her, because as it turns out, the killer is a man named Bruce McArthur. Bruce McArthur is not a person of colour around 30 years old. Bruce McArthur is white and a senior citizen. Ironically, since most serial killers are white, if she had been correct about the suspect’s race, these two would have been the more informative of her predictions. Instead, she was spectacularly wrong on both counts.

I would advise Ms. Reid to put aside her amateur detective work and instead concentrate on completing her actual doctoral work, for which she hopefully displays more aptitude. And I would advise the Toronto Star to require more critical thought from its reporters — and not just directed at the police.

No comments:

Post a Comment