EXTRA! EXTRA! Read all about it: New study finds 70-year-olds have worse memory than 20-year-olds!
No, I'm not trying to invoke the wrath of social science skeptics and budget-slashing politicians everywhere. Yes, I realize this reads like a potential case study in how researchers waste time and money exploring the obvious. But the next time critics try to tell you that psychology is merely the commonsense study of that which we already know, tell them to look more closely.
Indeed, the headline above tells only part of the story of a new study just published by two researchers in my own department at Tufts University, Ayanna Thomas and Stacey Dubois. They found that a sample of older adults (average age: 70) performed significantly worse on a memory task than a sample of college students (average age: 19). Hardly a prediction that requires knowledge of research design much less an advanced degree, right?
But the fascinating–not to mention practically important–conclusion offered by this same study is that the expected age difference only emerged among half of the participants. What was special about the 50% of research respondents who didn't show an age difference? Were these particularly active or intelligent older adults? Had they been taking some sort of memory-enhancing herbal supplement? No and no–they were no different in personal characteristics or past experiences than those who did show a decline in memory.
What was different were simply the circumstances under which the two groups of participants completed a memory test.
The task itself was the same for everyone: both younger and older adults were given a series of word lists to evaluate, charged with rating how pleasant or unpleasant each word was. Each list included 15 words semantically related to a particular target concept that wasn't actually part of the list. So one list included items like thread, sewing, pricked, haystack, and injection, all words related to the target concept needle. But needle itself was *not* on the word list.
After working through these lists, respondents passed a few minutes with a Sudoku puzzle filler task. Then, and only then, did the circumstances in which our two groups of participants found themselves diverge.
At this point, one group of respondents–let's call them Group A–was informed that the study was actually about memory rather than their evaluations of the pleasantness of words. Group A (comprised of 50% older and 50% younger adults) was then asked to read a paragraph describing previous research findings regarding age-related declines in memory.
With this in the way of introduction, participants were given a recognition test in which they had to look over a series of words to determine which ones they had seen in the earlier lists and which they had not. How did the older and younger adults in Group A do on this test? As you'd expect, the memory of older adults was less accurate. Specifically, they were more likely than their younger counterparts to incorrectly remember that the merely alluded-to target words, like needle, had been part of the original word lists.
But this age effect disappeared in Group B. These respondents–again, 50% older and 50% younger adults–read through and evaluated the very same word lists. They, too, were given a Sudoku puzzle for 5 minutes. But they were then given a very different context for the memory test that followed: They weren't told that it was a memory test.
Instead, Group B was instructed that the study was about language processing and verbal ability (and, accordingly, they were given a paragraph to read about previous research related to language). When then asked to complete the same recognition test as Group A did, the memories of the older and younger participants were now indistinguishable. In other words, armed with a different mindset–one focused on a domain in which negative stereotypes regarding older adults are not pervasive–older participants in Group B showed no sign of the increased false positive rate observed in Group A.
OK, so the moral of this memory study is hardly as dramatic as aging is all in your head. But the data do make a compelling case that what goes on in your head shapes how aging will impact you. Our stereotypes about what it means to grow old contribute to our actual experiences of growing old.
And more generally, this study also reminds us, once again, that we don't know everything there is to know about human nature. That many of the so-called truisms we assume about how the mind works are only half-right (or, in some cases, even less so). That searching for illuminating research conclusions in psychology is far easier than finding a needle in a haystack, even when the needle's not just an insinuated figment of someone else's false memory.
Like this post? Then check out Sam's forthcoming book, Situations Matter: Understanding How Context Transforms Your World (available now for pre-order). You can also follow Sam on Facebook here and on Twitter here. Book trailer video below: