, ,


Story and Digital Mischief by Warrigal Mirriyuula.

As we grow older we have the opportunity to witness and ponder the shifts and changes in the world around us. To note what used to be called the “passing parade”; to see first our children and then our grandchildren grow up, as we too grow, travelling our various life and career paths.

This is such a commonplace experience and our musings such an ineluctable outcome thereof that it’s usually put down to the “human condition”, what Sartre called the existential dilemma. It all boils down to “how do we feel, how should we think, how should we act”?

Another commonplace is the notion that as we age our cognitive abilities wane. We take longer to recall memories accurately and can’t program the DVD, we misname people and endure what is often professionally described as “age appropriate” memory loss.

But is this slow decline into la la land real?

Not according to new research led by Dr. Michael Ramscar of Tübingen University. He and his colleagues’ recently published work in Journal Topics in Cognitive Science seems to put the lie to established ideas about older brains and declining cognitive acuity.

The team discovered that most standard cognitive measures, which date back to the early twentieth century, are flawed. “The human brain works slower in old age,” says Ramscar, “but only because we have stored more information over time.”

One of the things that stood out for me was that they discovered this new truth by teaching computers to “read books”. The books were a proxy for reality. What was “read” simulating the experiences of a life-time. The reading computers were then interrogated and tested for recall and comprehension.

When the computer was only allowed to read a small amount, subsequent cognitive test results were the equivalent of a young adult, but when the computer had accumulated the equivalent of a lifetimes reading over decades the cognitive test results looked like those of an older person. The computer was slower, not because its processing capacity had declined but because its data base had increased substantially and all that extra data, read life experience, took longer to process.

Technology now allows researchers to make quantitative estimates of the number of words an adult can be expected to learn across a lifetime, enabling the Tübingen team to separate the challenge that increasing knowledge poses to memory from the actual performance of memory itself.

“Imagine someone who knows two people’s birthdays and can recall them almost perfectly. Would you really want to say that person has a better memory than a person who knows the birthdays of 2000 people, but can ‘only’ match the right person to the right birthday nine times out of ten?” asks Ramscar.

The answer appears to be “no.” When Ramscar’s team trained their computer models on huge linguistic datasets, they found that standardized vocabulary tests, which are used to take account of the growth of knowledge in studies of aging, massively underestimate the size of adult vocabularies. It takes computers longer to search databases of words as their sizes grow, which is hardly surprising but may have important implications for our understanding of age-related slowdowns. The researchers found that to get their computers to replicate human performance in word recognition tests across adulthood, they had to keep their capacities the same. “Forget about forgetting,” explained Tübingen researcher Peter Hendrix, “if I wanted to get the computer to look like an older adult, I had to keep all the words it learned in memory and let them compete for attention.”

The research shows that studies of the problems older people have with recalling names suffer from a similar blind spot: there is a far greater variety of given names today than there were two generations ago. This cultural shift toward greater name diversity means the number of different names anyone learns over their lifetime has increased dramatically. The work shows how this makes locating a name in memory far harder than it used to be. Even for computers.

Ramscar and his colleagues’ work provides more than an explanation of why, in the light of all the extra information they have to process, we might expect older brains to seem slower and more forgetful than younger brains. Their work also shows how changes in test performance that have been taken as evidence for declining cognitive abilities in fact demonstrates older adults’ greater mastery of the knowledge they have acquired.

Take “paired-associate learning,” a commonly used cognitive test that involves learning to connect words like “up” to “down” or “necktie” to “cracker” in memory. Using Big Data sets to quantify how often different words appear together in English, the Tuebingen team show that younger adults do better when asked to learn to pair “up” with “down” than “necktie” and “cracker” because “up” and “down” appear in close proximity to one another more frequently. However, whereas older adults also understand which words don’t usually go together, young adults notice this less. When the researchers examined performance on this test across a range of word pairs that go together more and less in English, they found older adult’s scores to be far more closely attuned to the actual information in hundreds of millions of words of English than their younger counterparts.

As Prof. Harald Baayen, who heads the Alexander von Humboldt Quantitative Linguistics research group where the work was carried out puts it, “If you think linguistic skill involves something like being able to choose one word given another, younger adults seem to do better in this task. But, of course, proper understanding of language involves more than this. You have also to not put plausible but wrong pairs of words together. The fact that older adults find nonsense pairs—but not connected pairs—harder to learn than young adults simply demonstrates older adults’ much better understanding of language. They have to make more of an effort to learn unrelated word pairs because, unlike the youngsters, they know a lot about which words don’t belong together.”

The Tübingen researchers concluded that we need different tests for the cognitive abilities of older people—taking into account the nature and amount of information our brains process.

“The brains of older people do not get weak,” says Michael Ramscar. “On the contrary, they simply know more.”

A lot more!

Note: I took my title from the Thomas Hood Poem of the same name. My father used to regularly recite the poem when the issue of memory and remembering came up. Over time the portion quoted was reduced to the first four lines.

For me, now, it’s the last four lines that truly illuminate our subject here.


The above story is based on materials provided by Universitaet Tübingen and Science Daily.

Journal Reference:

Michael Ramscar, Peter Hendrix, Cyrus Shaoul, Petar Milin, Harald Baayen. The Myth of Cognitive Decline: Non-Linear Dynamics of Lifelong Learning. Topics in Cognitive Science, 2014; DOI: 10.1111/tops.12078