Let’s consider human intelligence for a moment. Perhaps the best way to assess it comes in the form of the IQ test. While not quite a perfect barometer of intelligence, the test offers a pretty reliable and standardised way of testing and summarising how clever someone is.
The average person has an IQ of around 95-105. The average serial killer, according to The Serial Killer Information Center, has an IQ of 94.5. Slightly below the lower side of average. The stats prove that serial murderers are generally slightly less intelligent than the average member of society.
How about that?
That said, there are plenty of exceptions to the rule. In truth, serial killers appear across the scale of human intelligence. But what can we learn from that? Is there a connection between a killer’s IQ and their crimes…?
Let’s see if we can find out, shall we?
Cunning, sophisticated, elegant, fiercely intelligent… There are certain personality traits and characteristics which spring to mind when you consider the archetypal serial killer.
Of course, it doesn’t actually take a superior mind to kill another human being. Hollywood, however, begs to differ. The flair, artistry and reasoning behind the actions of the big screen serial murderers seen in the likes of Se7en and The Silence of the Lambs suggest that slaughter is an intellectual pursuit.
Nathan Leopold - 210
When rich kids Nathan Leopold and Richard Loeb kidnapped a local boy - 14 year-old Bobby Franks - in Chicago in 1924, they didn't have much of a motive. At least not a traditional one, anyway. When they bludgeoned him to death and dumped his corpse it wasn't for financial gain or revenge. It was merely to see if they could get away with it. Leopold and Loeb were arrogant thrillseekers who later became the basis for the Patricia Highsmith book and Alfred Hitchcock film Strangers on a Train. Both were smart, but it was Leopold who devised the fiendish plan. He was, unequivocally, a genius. Strangely enough, though? Their plan was terribly conceived and executed and the pair were rather quickly apprehended by police.
Ted Kaczynski - 167
Technically classified more as a ‘domestic terrorist’ than a serial killer, The Unabomber is still worthy of note here. After all, he did kill people. And he does have a fierce intelligence. The former professor of mathematics-turned-murderous-anarchist had a prodigious intellect and an IQ higher than that of Albert Einstein’s.
Charlene Gallego - 160
The married couple behind ‘The Sex Slave Murders’, Gerald and Charlene Gallego, were not - as you can imagine - very nice people. After kidnapping, raping, torturing and murdering 10 young women during their reign of terror, Charlene received a lesser sentence in exchange for testifying against her husband. It was a smart move. But then Mrs. Gallego is a smart woman, with an IQ of 160. She is now a smart, free woman.
Andrew Cunanan – 147
The killer of Giovanni Versace - amongst others - Andrew Cunahan was an oddly unknown character before the TV anthology series American Crime Story made him their focus for their second series, The Assassination of Giovanni Versace. Anyone who’s seen the show will know what a sly, manipulative and devious sociopath Cunahan was. And a smart one too.
Edmund Kemper - 145
Jeffrey Dahmer - 145
Few of us would use the word ‘genius’ when describing Jeffrey Dahmer, but maybe we should. The Milwaukee Cannibal is one of history’s most disturbed and infamous serial killers. But he was also, according to his IQ tests, damned clever too.
Dr. Harold Shipman - 140
You don’t become a doctor without being smart (the average doctor scores around 120 on IQ tests - much higher than the average person). Nor do you very nearly get away with killing almost 250 people. Yet while his IQ suggests that Harold Shipman was a genius, his actions suggest he was a cold and heartless psychopath.
Ted Bundy - 136
Ted Bundy was charming, handsome and clever. That was his whole schtick. Let’s not forget that he was also a vicious rapist and murderer of women too, though.
Tommy Lyn Sells - 100
A violent burglar and murderer, ‘The Coast to Coast Killer’ Tommy Lyn Sells hit the exact US average for IQ when tested after his arrest.
Richard Chase - 95
The Vampire of Sacramento’s estimated intelligence was normal, even if his crimes were anything but. A rapist, serial killer, necrophile and cannibal, Chase’s back catalogue of murderous deeds is truly off the scale. Before his murderous endeavours, he was an average student who completed high school with average grades and no disciplinary problems.
Henry Lee Lucas - 85
While he scored low on IQ tests, was dyslexic and had ADHD, Henry Lee Lucas was - at least in the context of the murdering duo he was in - ‘The Smart One’. He scored a full 11 points higher than his criminal associate Otis Toole.
Fred West - 84
A school dropout who worked most of his life as a labourer, Fred West’s mental capacity was such that Gloucestershire Police allocated him an ‘appropriate adult’ during interviews. His low intelligence could account for how easily manipulated he was by his wife Rose who, it’s widely believed, was the ‘brains’ behind the married couples evil deeds.
Gary Ridgway - 82
The Green River Killer killed between 50-70 women between 1982 and 2001 in the state of Washington. That’s a full 20 years that Gary Ridgway murdered with impunity, evading police capture. Yet he wasn’t a mastermind criminal. He was a factory worker with an IQ well below that of the average Joe.
Aileen Wuornos - 81
History’s most notorious female serial killer, Aileen Wuornos’ score suggests low intelligence, but the reality may well differ. It’s thought that Wuornos dismissed and resented the idea of being tested and didn’t complete it to the best of her ability.
Ottis Toole - 75
There is something of a thread here. While there’s clearly a range of IQs and not a single ‘set intelligence’ for serial killers, there does appear to be a definite link between intellect and style of killer.
Famed American criminologist Roy Hazelwood separated repeat murderers into two main groups - organised and disorganised. Committing crimes that are planned in advance, thought through meticulously and carried out coolly and with a steady hand, ‘organised’ serial killers generally have above average IQs. Whereas sloppy, impulsive and messy ‘disorganised’ killers tend to score much lower on such tests.
So, then. Serial Killers. Are they smarter or dumber than the average person? Well, as with most things in life… It all depends.