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I Knew It

January 20, 2014 Leave a comment Go to comments

pearlsswinememory

[Pearls Before Swine, January 12, 2014]

I’ve suspected for some time that the reason names of people elude me, even as I picture the people and provide details of their lives, is that I know too much. Each year, I have to find room in my brain for more and more people: friends and acquaintances, athletes and actors, musicians and artists, authors and journalists. It never ends. I succeed, for the most part, but recovering their names on demand is one task too many.

It turns out there’s an explanation for this. Thanks to Mark Liberman at Language Log, I learned last week of a new paper by a group of linguists at Tübingen on “the myth of cognitive decline.” (Also thanks to Liberman, I saw the Pearls Before Swine comic that fortuitously appeared eight days ago, which I have reproduced above. I would happily subscribe to the depicted Brain Alert service.)

Michael Ramscar and his Tübingen colleagues bring good news:

Because it is believed that cognitive abilities wither over the course of adulthood, population aging is thought to pose a serious threat to the world’s economic well-being (Watkins et al., 2005): As the proportion of cognitively impaired adults in the population increases, it is feared they will impose an ever-larger burden on the ever-smaller proportion of society still in full command of its cognitive faculties. Given this uncertain scenario, understanding the way our minds age could be considered the most significant matter that the psychological and brain sciences address.

In what follows, we consider the question of whether one might reasonably expect that performance on any measure of cognitive performance could or should be expected to be age- or, more specifically, experience-invariant. We shall suggest that, since the answer to this question is no, many of the assumptions scientists currently make about “cognitive decline” are seriously flawed and, for the most part, formally invalid. We will show that the patterns of response change that are typically taken as evidence for (and measures of) cognitive decline arise out of basic principles of learning and emerge naturally in learning models as they acquire more knowledge. These models, which are supported by a wealth of psychological and neuroscientific evidence (for reviews see Schultz, 2006; Siegel & Allan, 1996; Ramscar, Dye, & Klein, 2013a), also correctly identify greater variation in the cognitive performance of older adults, and successfully predict that older adults will exhibit greater sensitivity to the fine-grained properties of test items than younger adults. Given that the models run (and can be rerun) on computers, the possibility that any differences in their performance are due to aging hardware can be eliminated; instead, their patterns of performance reflect the information-processing costs that must inevitably be incurred as knowledge is acquired. Once the cost of processing this extra information is controlled for in studies of human performance, findings that are usually taken to suggest declining cognitive capacities can be seen instead to support little more than the unsurprising idea that choosing between or recalling items becomes more difficult as their numbers increase.

Aha! See, I’m not declining cognitively. I just know too much, as a result of which I also have greater sensitivity to fine-grained properties than you do. Cool!

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Categories: Cognition, Science
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