THE DOTAGE CURVE

08 February 2014 | By ken in Society

How Real Is It?

Conventional wisdom tells us that as we age, we slowly but inevitably decline. Our bodies lose energy and resilience. Our memories fail, and we are slow to come up with new ideas.

And science has pretty much gone along with this account, citing evidence culled from standard tests of memory, vocabulary and calculation. The older we get, the worse we do on such tests.

But maybe the problem is with the tests. A recent story in The New York Times, notes “a new kind of challenge to the evidence of a cognitive decline, from a decidedly digital quarter: data mining, based on theories of information processing.”

Michael Ramscar and a team of linguistic researchers from the University of Tübingen in Germany. “applied leading learning models to an estimated pool of words and phrases that an educated 70-year-old would have seen, and another pool suitable for an educated 20-year-old. Their model accounted for more than 75 percent of the difference in scores between older and younger adults on items in a paired-associate test, he said.”

That is to say, the larger the library you have in your head, the longer it usually takes to find a particular word (or pair). “It’s not that you’re slow. It’s that you know so much.”

From a different quarter, Dr. Laura Carstensen at at Samford, noted : “Given that most cognitive research asks participants to engage with neutral (and in emotion studies, negative) stimuli, the traditional research paradigm may put older people at a disadvantage.” Dr. Carstensen argued that this ignore a “positivity effect,” the bias of older people to recall words and associations with positive connotations.

Zach Hambrick, a psychologist at Michigan State University, discriminates two kinds of intelligence, fluid and crystallized: “fluid intelligence” includes short term memory, analytic reasoning, and the ability to abstract information from its context; while “crystallized intelligence,” is about accumulated knowledge, vocabulary and expertise. Hambrick and his colleagues have shown that crystallized knowledge . . . climbs sharply between ages 20 and 50 and then plateaus, even as the fluid kind (like analytical reasoning) is dropping steadily — by more than 50 percent between ages 20 and 70 in some studies.”

“In essence, what Ramscar’s group is arguing is that an increase in crystallized intelligence can account for a decrease in fluid intelligence.” In other words, our senior moments are offset by an expanded knowledge base and expertise.

The Times notes that such new studies are “not likely to overturn 100 years of research,” or at least that many years of conventional wisdom. Neuroscientists have some reason to believe that neural processing speed, like many reflexes, slows over the years; anatomical studies suggest that the brain also undergoes subtle structural changes that could affect memory. We are not crazy to think that our minds actually do decline with age. (See, “The Older Mind May Just Be a Fuller Mind.“)

Still the picture is turning out to be far more complex than most of us had assumed. The Times pointed out that in the past “some scientists have questioned this dotage curve. But these challenges have had an ornery-old-person slant: that the tests were biased toward the young, for example. Or that older people have learned not to care about clearly trivial things, like memory tests.” I know that I have such an ornery slant myself.

But it is also true that as I get older I care less about impressing others with things that don’t matter to me. I am careful to use my energy wisely. I care about fewer things – but then I care more about the things that do matter.

In an age that celebrates youth, it is good to have support for a more nuanced view of aging.

One Comment on “THE DOTAGE CURVE”

  1. HI Ken,

    I read this in the Times with interest….I like your slant: a more NUANCED vies of aging. Whatever the case, worrying about forgetting surely can’t help us retrieve more and so I salute this work and your reminding us of it. We do have more stored input and it makes some mechanical sense–if that’s a proper metaphor–that retrieval would be slower. Anyway, here’s to caring more deeply about fewer things…

    best
    Kathy

     

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