What happens to our minds and memories in healthy ageing?

In our recent paper, The myth of cognitive decline, my colleagues and I suggest that the answer to this question is, “it’s complicated.” And if you think that the answer involves a steady deterioration of cognitive function, we present a series of findings that may make you think again.

Take, for instance, our ability to “retrieve” words from our memories: It’s widely believed that this ability declines as we get older. However, when we took a close look at the tests used to measure memory performance across the lifespan, we found that the truth of the matter is far less simple. Whether a word becomes harder (or easier) to recall with age can depend both on the kind of word tested, and the kind of test used. While many people find names increasingly hard to recall as they get older, on some tests of word recall, memory retrieval is unaffected by ageing. On other tests, performance actually improves with age. (I’ll talk more about this in more detail in a later post, but for now, Mark Liberman over at Language Log offers a lucid introduction to the way retrieval performance varies by test).

Not only did we find that a researcher’s choice of test can determine whether cognitive functioning appears to decline or improve with age, we also found that the results of the same cognitive test can suggest age-related declines or improvements, simply as a result of the context in which people are tested.

The methods we use to establish our findings are fairly complicated. For our journal article, we assumed that our readers would have a fairly high degree of scientific training, and so we kept the presentation of our methods and results brief. Because our results are likely to be of interest to people who have not had that training, I thought it might be helpful to write some expanded introductions to our work, so that our findings and their implications can be more widely understood.