I think you can change one's IQ.
I recently stumbled upon a paper published last year that suggests that fluid intelligence can be trained and that the training effect is dosage-dependent:
Improving fluid intelligence with training on working memory Jaeggi et al. PNAS. 2008.
Fluid intelligence (Gf ) refers to the ability to reason and to solvenew problems independently of previously acquired knowledge. Gf is critical for a wide variety of cognitive tasks, and it isconsidered one of the most important factors in learning. More- over, Gf is closely related to professional and educational success, especially in complex and demanding environments. Although performance on tests of Gf can be improved through direct practice on the tests themselves, there is no evidence that training on any other regimen yields increased Gf in adults. Furthermore, there is a long history of research into cognitive training showing that, although performance on trained tasks can increase dramatically, transfer of this learning to other tasks remains poor. Here, we present evidence for transfer from training on a demanding working memory task to measures of Gf. This transfer results even though the trained task is entirely different from the intelligence test itself. Furthermore, we demonstrate that the extent of gain in intelligence critically depends on the amount of training: the more training, the more improvement in Gf. That is, the training effect is dosage-dependent. Thus, in contrast to many previous studies, we conclude that it is possible to improve Gf without practicing the testing tasks themselves, opening a wide range of applications.
Speaking of IQ, Linda S. Gottfredson recently published Logical fallacies used to dismiss the evidence on intelligence testing which might be of interest to some of the readers.
For anybody who's interested in trying the "dual n-back" task mentioned in Jaeggi et al., there is Brain Workshop, a free, open-source implementation, with a lively community of users.
Link: "Don't: The secret of self-control", Jonah Lehrer. The New Yorker. May 18, 2009.
Article Summary
Walter Mischel, a psychologist at Columbia University, has spent a long time studying what correlates with failing or passing a test intended to measure a preschooler's ability to delay gratification. The original experiment, involving a marshmallow and the promise of another if the first one remained uneaten for fifteen minutes, took place at Bing Nursery School in the "late 1960's". Mischel found several correlates, none of them really surprising. He discovered a few methods that allowed children to learn better delay gratification, but it is unclear if the learning the tricks changed any of the correlations. He and the research tradition he started are now waiting for fMRI studies, because that's what the discriminating 21st century psychologist does.
Best line: "'I know I shouldn't like them,' she says. 'But they're just so delicious!'"
Article Criticism
The New Yorker is not exactly meant as a science journal for scientists, so it leads and weaves a couple human interest stories in with the boring science parts. We hear from a 'high delayer' (someone who did well at the test) and her 'low delayer' brother. This sort of opening seems terribly common in popular science writing, and it's so infuriating because it primes the reader with the conclusions of the science before the science is even discussed. The high delayer goes on to become a social psychologist; the low delayer goes to Hollywood and is now working on becoming a producer. So already we see anecdotal evidence that high delayers are successful, low delayers are unsuccessful, and that there's not a genetic component (because brothers and sisters share so much genetic material — right?).
At this point the author gives the impetus for Mischel's study as conversations he had with his daughters after they left Bing. Of course, that's not the whole story; that just explains the longitudinal part. According to Mischel's bio halfway through the article, he's been doing experiments like the marshmallow test every since his Ph. D. The article cites a chocolate bar test he did in Trinidad in 1955 that was intended to examine the racial stereotypes of Africans and East Indians.
The only technique mentioned that helped increase children's ability to delay gratification was "...a simple set of mental tricks — such as pretending the candy is only a picture, surrounded by an imaginary frame ...." However, buried on the next-to-last page of the article, we find that "...it remains unclear if these new skills persist over the long term."
Background Literature
I dug up the delay test article ("", W Mischel, Y Shoda, and MI Rodriguez (26 May 1989) Science 244 (4907), 933"), which those without subscription can find here, and found a few more practical applications. Mischel et. al. found, for instance, that "attention to the rewards consistently and substantially decreased delay time" (934). This suggests that if you would like to delay a reward, it's best not to see the reward directly. However, another experiment showed that images of the reward made delaying gratification easier. By far, though, the best technique discovered by the study was self-distraction. Even when the reward was present in the room with them, children who sung songs to themselves or played with toys did much better at the delay test than those who didn't.
In conclusion, I found neither the article nor the study itself practically helpful. I was annoyed by the human-interest propaganda that littered the article and the narrowness of the original study. As far as beating akrasia goes, the best advice I can give is for improving short-term gratification delay, practice self-distraction and avoid tempting yourself with the actual reward. If you think a visual reminder of the reward would help, settle for a picture.