Thursday, January 12, 2012


I previously wrote a post about one of the themes from the film Limitless: the idea that some pills can make us smarter. That they can enhance our cognitive abilities, such as our ability to pay attention, to learn, to remember, to be creative or think "out of the box." In essence, such pills-cognitive enhancers-hold out the promise of intellectual superpowers, at least for some of us. The film (and the book, The Dark Fields by Alan Glynn, on which it is based) portrays a glimpse of what it would be like to have such seemingly limitless enhanced powers.

In a recent article, psychologists Thomas Hills and Ralph Hertwig suggest that there may well be limits on how enhanced our cognitive abilities can become, or how enhanced they can become without some significant cost or "side effect." As an example they hold up caffeine intake, which can help us focus and stay alert (and so makes caffeine a cognitive enhancer), but too much caffeine can make us anxious or impair our fine motor coordination. In this case, more isn't necessarily better.

Even when a more enhanced ability might be even better, Hill and Hertwig suggest that humans haven't evolved to be more enhanced without a cost. They point to "S," the man with a famous memory. S could remember lists of words or numbers of astounding length, and could recite them from memory backwards as easily as forwards. Once reading or hearing something, S never forgot it. However, S couldn't remember faces very well. He also couldn't shut out the associations and memories that were triggered by things he read and heard. His extraordinary memory came at the cost of other "normal" abilities. (You can read more about S in The Mind of a Mnemonist: A Little Book About a Vast Memory by Aleksandr Luria.)

This seemingly built-in compensation for extraordinary abilities is highlighted in an article by Allan Snyder in which he discusses people who are savants-who have extraordinary pockets of knowledge or skills that contrast sharply with the rest of their abilities. Dustin Hoffman's character in the film Rain Man is an example of a savant. Because of how the brains of savants work, they can access information that most of us can't, but in turn they are less likely to understand the information. Metaphorically, they can see the trees in detail but don't understand that together they create a forest. Snyder proposes that it is the lack of the ability to see the whole-to process that many trees indicate a forest-that gives rise to their being able to see the trees in such detail.

Researchers have temporarily been able to induce savant-like skills in "normal" participants through transcranial magnetic stimulation (TMS), a procedure in which a coil placed on the scalp emits magnetic pulses into selected areas of the brain, briefly inhibiting those brain areas, and allowing other brain areas to become more active. Using TMS in this way, researchers have found that "normal" non-artist participants can temporarily draw better (and are able to pay more attention to detail), become better proofreaders, and become better at guessing the number of elements in a container (e.g., akin to the number of marbles in a jar), among other abilities. The specific ability that improves depends on the exact position of the TMS coil.

The fact that TMS can temporarily enhance a specific ability by briefly disabling another ability is part of the point Hill and Hertwig make: A given ability is only a plus in certain contexts, and the "side effects" or costs of that ability can, in other contexts, create deficits. Being able to remember everything you read is great for law school and being a lawyer, but it creates problems if you can't recognize the presiding judge from last year's case (but she recognizes you!).

It appears that our ability to be enhanced may not be limitless after all.

Copyright 2012 by Robin S. Rosenberg. All rights reserved.
Robin S. Rosenberg is a clinical psychologist. Her website is and she also blogs on Huffington Post.Her most recent book is The Psychology of the Girl with the Dragon Tattoo.


Hills, T., & Hertwig, R. (2011). Why aren't we smarter already: Evolutionary trade-offs and cognitive enhancements. Current Directions in Psychological Science, 20, 373-377.

Snyder, A. (2009). Explaining and inducing savant skills: Privileged access to lower level, less-processed information. Philosophical Transactions of the Royal Society, Biological Sciences. 364, 1399-1405.

No comments:

Post a Comment