The Seattle Longitudinal Study of Adult Intelligence

The Seattle Longitudinal Study of Adult Intelligence has followed a group of more than 5000 people for well over four decades. The program began in 1956 and participants have been tested across a whole gamut of mental and physical abilities at seven year intervals since that date.

The study has found:

  • no uniform pattern of age-related change across all intellectual abilities
  • some support for the idea that abilities that are primarily genetically determined tend to decline earlier than abilities that are primarily acquired through schooling or experience (although there may be gender differences here)
    • although abilities that are primarily genetic may decline earlier, abilities acquired through training decline more steeply after late 70s the change in perceptual speed begins in young adulthood and declines in a linear fashion (that is, the rate of decline is constant)
    • the rate and magnitude changes in intelligence seen in those entering old age showed greater decline in the 1st 3 cycles (till 1970); at the same time, younger members are scoring lower on tests at the same age.
    • a decline in psychometric abilities is not reliably observed before 60, but is reliably observed by 74. However, even by 81, fewer than half showed reliable decrements over the past seven years.
    • the size of this decline however is significantly reduced when age changes in perceptual speed are taken into account.
    • substantial cohort / generational differences have been observed. Later-born groups have attained successively higher scores at the same ages for inductive reasoning, verbal meaning, and spatial orientation; however, they’ve scored successively lower in number skill and word fluency (number skill peaked with the 1924 cohort). These changes presumably reflect educational changes.
    • substantial similarity between parents and their adult children and between siblings has been found for virtually all mental abilities and measures of flexibility (the exceptions are the attitude measure of social responsibility, and a measure of perceptual speed). The magnitude of similarity varied for different abilities, and was closer between parent & child than between siblings.
    • the following variables may reduce the risk of cognitive decline in old age:
      • absence of chronic diseases
      • a complex and intellectually stimulating environment
      • a flexible personality style at mid-life
      • high intellectual status of spouse
      • maintenance of high levels of perceptual processing speed
    • cognitive training studies suggested that the observed decline in many community-dwelling older people is probably a function of disuse and is often reversible. Some 2/3 of participants in a cognitive training program showed significant improvement, and 40% of those who had declined significantly were indeed returned to their earlier (pre-decline) level of cognitive functioning. These training gains were retained over seven years.



  1. Schaie, K. Warner 1998. The Seattle Longitudinal Studies of adult intelligence. In M. Powell Lawton & Timothy A. Salthouse (eds) Essential papers on the psychology of aging. NY: NY Univ Pr. Pp263-271.

tags memworks: 

tags problems: 

Homework revisited

At the same time as a group of French parents and teachers have called for a two-week boycott of homework (despite the fact that homework is officially banned in French primary schools), and just after the British government scrapped homework guidelines, a large long-running British study came out in support of homework.

tags strategies: 

tags memworks: 

The Role of Context in Shaping Cognitive Development

I'm a great believer in the wide-ranging, and widely-underestimated, effects of context - on all manner of things. I'm also a fan of the view that intelligence - so widely regarded as a fixed attribute - is also partly influenced by context. So I was pleased to see an article by Stephen Ceci - intelligence guru - discussing the role of context in cognitive development, and the implications of that for education.

Stephen Ceci at This View of Life:

When it comes to mental ability, many of our human talents were shaped by evolutionary forces that arose under the demanding conditions of life on the African savannah 35,000 to 50,000 years ago. Evolutionary psychologists have linked many of our current attributes to these earlier environmental challenges faced by our predecessors (Kanazawa, 2005). This much is noncontroversial. What is less agreed upon, however, is the extent to which present-day cognition is under the control of local conditions—that is, the specific physical, motivational, and psychological conditions under which humans attempt to solve problems. The argument I am making is that it is logically unsafe to claim that our successful performance on cognitive tasks today reflects our evolutionary preparation because the flip side is that our unsuccessful performance reflects our lack of evolutionary preparation—which may be wrong. In fact, a great deal of developmental research demonstrates that even when evolution has prepared us to undertake certain cognitive operations, successful performance depends on local conditions.

Educational implications. The goal of education is not to drum facts and concepts into children, but to create awareness of how these facts and concepts can be generalized to situations that differ from the ones used to teach them. Thus, the key is transferring knowledge from the contexts used to teach it to ones encountered outside of school. And yet, a great deal of empirical research has documented that young and old, high IQ and low IQ, schooled and unschooled, all fail to transfer learning to new contexts that differ from the context in which they were originally taught (e.g., Ceci, 1996; Leshowitz, 1989). The research described here suggests that context is a constituent of cognition, not something adjunctive or peripheral to it. This view of cognition-in-context has several implications for education.

View of Life article

tags memworks: 

Does music training make you smarter?

Have to say I was a bit disappointed by this, seeing as how I'm a big fan of childhood instruction in music. But it must be remembered that even if some of the benefits have been a bit overblown, there are other long-term benefits of music training. I see this more as a reminder that the picture is a complicated one - regarding both music, and video games.

Ingrid Wickelgren at Scientific American:

Journalist and author Lydia Denworth reported in her article, “How Video Games Change the Brain,” in the January Scientific American Mind, that practicing certain types of video games (the violent first-person shooter ones) does enhance a huge variety of basic thinking skills such as visual attention and spatial reasoning. Practicing music does not. She writes: “With practice, a violinist can play a Mozart string concerto beautifully, but that will not make her better at much else.”

That sentence provoked the ire of more than one reader. … But Denworth stands by her statement.

Continue reading Scientific American article

tags memworks: 

Strategy use more important than IQ for academic achievement

Nice review in Scientific American of some of the research showing that the active use of a wide array of effective learning strategies is more important for academic achievement than ‘ability’.

... The researchers related their findings to The Matthew Effect: those with high intrinsic motivation and effective learning strategies will tend to increase their ability, while those without those characteristics will tend to decrease their ability. Over time, the gap between those with higher ability and those with lower ability will widen. Which is all the more reason why we ought to set up the right conditions for active engagement for everyone, and teach people the proper strategies for success. ...

Read the full article

tags memworks: 

A defense of working memory training

There’s been a certain amount of criticism of working memory training recently. Scott Barry Kaufman in the Scientific American has put out an excellent article critiquing the criticism. Among his points (most of which I have previously made), he notes:

These nuanced effects suggest that personal characteristics should be taken into account when considering the effectiveness of cognitive training. …

Next, it’s important to consider that working memory training is most helpful for those who need it the most. …

[Nevertheless] The evidence suggests that the activities that show the strongest and most widespread effects on cognitive functioning are those that target the “whole person,” ...

Cook rightly notes that the effects of the large majority of working memory training programs don’t generalize well beyond the specific skills that are targeted. ...

It’s also important to keep in mind that regardless of the method, working memory improvements are transient. Repeated practice and challenge is essential to maintaining improvements in any kind of cognitive training or else they’ll very likely decline rapidly. ...

Read the full article

tags memworks: 

Practice counts! So does talent

The thing to remember about Ericsson’s famous expertise research, showing us the vital importance of deliberate practice in making an expert, is that it was challenging the long-dominant view that natural-born talent is all-important. But Gladwell’s popularizing of Ericsson’s “10,000 hours” overstates the case, and of course people are only too keen to believe that any height is achievable if you just work hard enough.

The much more believable story is that, yes, practice is vital — a great deal of the right sort of practice — but we can’t disavow “natural” abilities entirely.


Campitelli, G., & Gobet F. (2011).  Deliberate Practice. Current Directions in Psychological Science. 20(5), 280 - 285.

Campitelli, G., & Gobet, F. (2008). The role of practice in chess: A longitudinal study. Learning and Individual Differences, 18, 446–458.

Gobet, F., & Campitelli, G. (2007). The role of domain-specific practice, handedness and starting age in chess. Developmental Psychology, 43, 159–172.

Hambrick, D. Z., & Meinz, E. J. (2011). Limits on the Predictive Power of Domain-Specific Experience and Knowledge in Skilled Performance. Current Directions in Psychological Science, 20(5), 275 –279. doi:10.1177/0963721411422061

Hambrick, D.Z., & Engle, R.W. (2002). Effects of domain knowledge, working memory capacity and age on cognitive performance: An investigation of the knowledge-is-power hypothesis. Cognitive Psychology, 44, 339–387.

Hambrick, D.Z., Libarkin, J.C., Petcovic, H.L., Baker, K.M., Elkins, J., Callahan, C., et al. (2011). A test of the circumvention-of-limits hypothesis in geological bedrock mapping. Journal of Experimental Psychology: General, Published online Oct 17, 2011.

Hambrick, D.Z., & Oswald, F.L. (2005). Does domain knowledge moderate involvement of working memory capacity in higher level cognition? A test of three models. Journal of Memory and Language, 52, 377–397.

Meinz, E. J., & Hambrick, D. Z. (2010). Deliberate Practice Is Necessary but Not Sufficient to Explain Individual Differences in Piano Sight-Reading Skill. Psychological Science, 21(7), 914–919. doi:10.1177/0956797610373933


tags strategies: 

tags memworks: 

Choosing when to think fast & when to think slow

I recently read an interesting article in the Smithsonian about procrastination and why it’s good for you. Frank Partnoy, author of a new book on the subject, pointed out that procrastination only began to be regarded as a bad thing by the Puritans — earlier (among the Greeks and Romans, for example), it was regarded more as a sign of wisdom.

tags study: 

tags memworks: 

Intelligence isn’t as important as you think

Our society gives a lot of weight to intelligence. Academics may have been arguing for a hundred years over what, exactly, intelligence is, but ‘everyone knows’ what it means to be smart, and who is smart and who is not — right?

Of course, it’s not that simple, and the ins and outs of academic research have much to teach us about the nature of intelligence and its importance, even if they still haven’t got it all totally sorted yet. Today I want to talk about one particular aspect: how important intelligence is in academic success.


Chamorro-Premuzic, T., & Furnham, A. (2003). Personality traits and academic examination performance. European Journal of Personality, 17(3), 237-250. doi:10.1002/per.473

Duckworth, A. L., & Seligman, M. E. P. (2005). Self-discipline outdoes IQ in predicting academic performance of adolescents. Psychological science, 16(12), 939-44. doi:10.1111/j.1467-9280.2005.01641.x

Furnham, A., & Chamorro-premuzic, T. (2005). Personality and Intelligence : Gender , the Big Five , Self-Estimated and Psychometric Intelligence. International Journal of Selection and Assessment, 13(1), 11-24.

Furnham, A., Rinaldelli-Tabaton, E. & Chamorro-Premuzic, T. (2011). Personality and Intelligence Predict Arts and Science School Results in 16 Year Olds. Psychologia, 54 (1), 39-51.

von Stumm, S., Hell B., & Chamorro-Premuzic T. (2011). The Hungry Mind. Perspectives on Psychological Science. 6(6), 574 - 588.

tags memworks: 

tags study: 

tags strategies: 


Subscribe to intelligence