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From The Skeptic: Top Ten Myths of Popular Psychology

September 3, 2010 Leave a comment

10-09-01.

Top Ten Myths of Popular Psychology

Virtually every day, the news media, television shows, films, and Internet bombard us with claims regarding a host of psychological topics: psychics, out of body experiences, recovered memories, and lie detection, to name a few. Even a casual stroll through our neighborhood bookstore reveals dozens of self-help, relationship, recovery, and addiction books that serve up generous portions of advice for steering our paths along life’s rocky road. Yet many popular psychology sources are rife with misconceptions. Indeed, in today’s fast-paced world of information overload, misinformation about psychology is at least as widespread as accurate information. Self-help gurus, television talk show hosts, and self-proclaimed mental health experts routinely dispense psychological advice that is a bewildering mix of truths, half-truths, and outright falsehoods. Without a dependable tour guide for sorting out psychological myth from reality, we’re at risk for becoming lost in a jungle of “psychomythology.”

Myth #1: We Only Use 10% of our Brains

Whenever those of us who study the brain venture outside the Ivory Tower to give public lectures, one of the questions we’re most likely to encounter is, “Is it true that we only use 10% of our brains?” The look of disappointment that usually follows when we respond, “Sorry, I’m afraid not,” suggests that the 10% myth is one of those hopeful truisms that refuses to die because it would be so nice if it were true. In one study, when asked “About what percentage of their potential brain power do you think most people use?,” a third of psychology majors answered 10%.1 Remarkably, one survey revealed that even 6% of neuroscientists agreed with this claim!2 The pop psychology industry has played a big role in keeping this myth alive. For example, in his book, How to be Twice as Smart, Scott Witt wrote that “If you’re like most people, you’re using only ten percent of your brainpower.”3

There are several reasons to doubt that 90% of our brains lie silent. At a mere 2–3% of our body weight, our brain consumes over 20% of the oxygen we breathe. It’s implausible that evolution would have permitted the squandering of resources on a scale necessary to build and maintain such a massively underutilized organ. Moreover, losing far less than 90% of the brain to accident or disease almost always has catastrophic consequences.4 Likewise, electrical stimulation of sites in the brain during neurosurgery has failed to uncover any “silent areas.”

How did the 10% myth get started? One clue leads back about a century to psychologist William James, who once wrote that he doubted that average persons achieve more than about 10% of their intellectual potential. Although James talked in terms of underdeveloped potential, a slew of positive thinking gurus transformed “10% of our capacity” into “10% of our brain.”5 In addition, in calling a huge percentage of the human brain “silent cortex,” early investigators may have fostered the mistaken impression that what scientists now call “association cortex” — which is vitally important for language and abstract thinking — had no function. In a similar vein, early researchers’ admissions that they didn’t know what 90% of the brain did probably fueled the myth that it does nothing. Finally, although one frequently hears claims that Albert Einstein once explained his own brilliance by reference to 10% myth, there’s no evidence that he ever uttered such a statement.

You could lots more to this list: having a stroke is not consequence free, for example. Losing part of your brain is generally irrevocable, and requires lots of rehabilitation (unless you are Lisbeth Salander of course, in which case all will be well, even after being shot in several parts of your brain simultaneously!).

The rest of the list is at the link above.

Neuroanatomy, bullets and brain damage in ‘The Girl With the Dragon Tattoo’ [The Millennium Trilogy by Stieg Larsson]

April 3, 2010 1 comment

Like at least 27 million other people, I bought and read all three volumes of the late Stieg Larsson’s Millennium trilogy (The Girl with the Dragon Tattoo, The Girl who Played with Fire, and The Girl who Kicked the Hornet’s Nest). All three books are in the current top ten best sellers in Ireland. I’ve also been to see the first film of the series (in Swedish, with English subtitles). The books are all a bit daft, but hugely enjoyable and compulsively readable – Larsson must have had great fun dreaming up the cast of variously weird, wonderful, and way-out characters in these books. The film was enjoyable too, if you like stark, grey, colour-desaturated Swedish landscapes with the occasional ageing and semi-crazed nazi, vicious intrafamily feuds, intergenerational inheritors of murderous traditions and dreary, near-endless rain and snow (seems I do). The lead female character, Lisbeth Salander, something of a social misfit (perhaps with a mild case of Asperger Syndrome), is an accomplished computer hacker and is reasonably skilled in martial arts and the use of golfclubs to demotivate murderers from the object of their predatory desires.

Towards the end of second volume of the series, Lisbeth is shot in the head with a .25 calibre gun (she survives). Larsson describes the wound thus (p 550, Quercus paperback edition):

“The third bullet caught her about two centimetres below the top of her left ear… The lead came to rest in the grey matter about five centimetres beneath the cerebral cortex by the cerebrum.”

In volume three, two medics work to save her and remove the bullet. One operates, the other (who claims to have a certain amount of alcohol on board), observes and makes suggestions. On page 9 (again Quercus paperback edition), the bullet wound is now described as ‘Entry wound just above the left ear’ (hmm). On page 11, one asks the other for a diagnosis. The reply is: ‘It entered at the temple, and the stopped about four centimetres into the brain. It’s resting against the lateral ventricle’. A conversation ensues about bone fragments and their potential for damage. One medic says the bone fragments are the cause  for concern, as they might kill her, as they are embedded in brain tissue. The other then remarks they are in the part of the brain associated with ‘numbers and mathematical capacity’, eliciting a sceptical response. (However, a bullet this deep in the brain would surely give anyone pause for thought, even if they were somewhat under the influence of alcohol).

But, reading all this as a neuroscientist, makes me give a sceptical response too; the various descriptions of  where the bullet has travelled really make little sense at all. If she was shot two centimetres below the top of the ear (but presumably not through the pinna, the outer part of the ear), how does the bullet end up passing through the temple? The neuroanatomical description of the bullet trajectory makes no sense either. The bullet is described as ‘to rest in the grey matter about five centimetres beneath the cerebral cortex by the cerebrum’. However: the grey matter is what comprises the cerebral cortex; the cerebrum is merely the term for what is usually referred to as ‘the brain’ (excluding the brain stem and cerebellum).

Five centimetres into the brain is quite a distance into the brain, and would likely cause enduring damage to a variety of functions (depending on location – but the bullet location varies!). If the bullet is close to or above the ear, then it can’t be close to the lateral ventricle, which is in a distinctly different location. There is a part of the brain associated with numerical and mathematical capacity (well, there must be) – it is usually regarded as the left parietal lobe (and the subregion of the angular gyrus) in right-handed individuals. Damage to this region is associated with the syndrome of acalculia, the loss of the ability to use and manipulate numbers. Again, this all a bit of distance from the three different places in the brain that poor Lisbeth has been shot with the one bullet! If the bullet has travelled five centimetres into the brain (assuming the top of the ear description is the accurate one), then depending on the trajectory, it just might have passed through the angular gyrus, travelling in a straight line toward the corpus callosum, or perhaps up a bit to posterior cingulate or anterior retrosplenial cortex (all midline structures). If it travelled at a downward angle, then it gets a lot more complicated. It won’t get near the lateral ventricle in either case; there is, instead, a wide choice of structures (both thalamic and non-thalamic) for the bullet to compromise.

What’s the lesson here? I’ve no idea (except that I should get out more, perhaps).