23 October 2009

Does your brain slow down as you get older?

People often say that your brain slows down as you get older, but is this true and if so why?

Adam Gazzaley of the University of California ran tests where he asked two groups of people, one aged 19 to 33 years and the other group aged 60 to 72, to perform memory tasks while wired up to an electrocephalogram machine.

What they found was that the speed of the brains in older and younger people was similar, but that the older participants performed less well on the memory tests because their brains were not as good at blocking irrelevant information. They experienced more distractions in the early part of each test and it was this delay that caused them to perform less well.

However, when the older participants were divided into the better performers and those who did less well, the results from the better performers were comparable with those of the younger people. This slowing of the brain is therefore not something that happens to everyone, but the tendency for it to happen does increase with age.

The next step in the research is to find out why it happens and what can be done about it.

On the other hand, I think I quite like my ability to be distracted!


  1. thamk you for this posting. do you think that the stroop effect effects older people more?

  2. For anyone who doesn’t know, the Stroop Test was designed to measure a person’s reaction time to a task. The task was to say out loud the colour of a word where the word described a different colour. For example, if the word “red” was written in yellow, then the person would have to say “yellow”. More recently the test has been popularised by a mental exercise game on the Nintendo DS.

    To answer the question, it is likely that older people will have a slower response time to the Stroop Test for the very reason that it is essentially a distraction test – i.e. can you ignore the word while assigning a word to the colour?

    It is also true that on average, more left-brained people find the task easier than more right-brained people for the simple reason that left-brained people tend to process information sequentially whereas more right-brained people process information more simultaneously, and are therefore more likely to be distracted by the word. It is therefore entirely possible that an older left-brained person might outperform a younger right-brained person.

    All this proves is that the results from simple tests such as this are only reliable if they are performed on large numbers of people. Where individuals are concerned, the results are interesting but not very meaningful.

  3. The caveman was a happy and easy going chap. No tests, no mumbo jumbo, no aftershave etc. We have gone down hill since that time and I for one only, repeat only, go for things and pleasures that I feel caveman would have liked.

  4. I totaly disagree with this test it shows nothing and proves nothing useful!

  5. It rather depends on what you mean by “useful”. There is no doubt that the Stroop Test highlights differences in the speed of mental processing between different people and that those differences can be statically proven to relate to attributes such as age and neurological dominance. However it is also true that those differences could also be demonstrated in other ways and that a person’s performance using the Stroop Test improves with practice.

  6. Hello, I'm a student doing a research project on brain stimulation in elders and younger people. I was wondering if you could tell me these results and how you obtained them. Could you please forward or post the link to this particular study. Thank you!

  7. The research was carried out by Dr Adam Gazzaley and his team at the Neuroscience Imaging Centre of the University of California, San Francisco, where they have undertaken extensive research into various aspects of cogitative decline. Most of their research findings can be found via the PNAS website (www.pnas.org) which is short for the Proceedings of the National Academy of Sciences of the United States. Some of their articles are ‘open access’ but for others you will need to be a subscriber.

    Good luck with the research and do let us know what you discover.


* Analytics tracking code