Wise, and Otherwise
Baltes, Paul B., Natural History
Biologists tend to treat aging, almost by definition, as a phenomenon of decline. But the course of a human life is more than just the inevitable outcome of biology. Human development, and thus aging as a part of this process, reflects the influence of two streams of inheritance: genetic and cultural. Two human accomplishments illustrate this: the ability of most of us to read and write and the tremendous increase in longevity witnessed during this century as a result of better medicine and more healthful life styles. Our genes provide the potential for both accomplishments, but neither would have been possible without the cumulative gains of human culture.
During the last decade, at Berlin's Max Planck Institute for Human Development, my colleagues (especially Reinhold Kliegl, Jacqui Smith, and Ursula Staudinger) and I have been studying the gains and losses of the aging mind. We distinguish between two major types of intellectual function: mechanics (information processing) and pragmatics (factual knowledge and problem solving). We argue that biological conditions reign supreme in the mechanics of the mind and that decline with aging is therefore likely. In the area of cognitive pragmatics, however, the power of culture unfolds, offering at least the possibility of gains with age.
To use a computer term, the cognitive mechanics are the "hardware" of the mind--the input of sensory information, visual and motor memory, and simple processes of discrimination and categorization. How quickly and accurately, for example, can we make distinctions between colors or geometric forms? How well do we remember simple visual or auditory stimuli?
To measure how mental hardware may deteriorate with age, we test basic memory skills of young and older adults. We ask participants in our research to memorize a long list of words, say, thirty nouns: car, plane, house, chair, and so on. To make the. task more difficult, we require that they remember not only the words, but also the order in which they were given.
When words are presented once at a speed of about two seconds per word, most of us can remember a string of five to seven words without the help of a memory technique. Remembering longer lists is possible, however, with the help of a memory strategy known since ancient times: the method of loci. To use this technique, you first learn a fixed list of places, such as the Eiffel Tower, the Berlin Wall, the Louvre, the Great Wall of China, the Golden Gate Bridge. You need as many places as there are words to remember. Once acquired, the list is a kind of mental map that can be used time and time again.
The next step is to form a mental picture, connecting each word on the list with one of the locations. For example, if the first word were car and the first place on your list of locations were Eiffel Tower, you might come up with a mental picture of a Mercedes dangling from the top of the Eiffel Tower. Then you move on to the next word and connect it visually with the next place on your mental map. Later, when asked to recall the entire list of words, you revisit the locations, one by one, retrieve the mental picture for each place, and decode it into the word to be remembered. With enough practice, you can remember long lists of words this way, and all in the correct order. Some people reach into the hundreds.
Because the mental operations required by the method of loci are part of the mind's basic biological hardware, we expected that acquiring and using the method should be fairly simple. And indeed, this is so. Almost anyone can learn the method of loci and, after just a few practice sessions, be pretty good at it.
But what about performance in old age? A typical seventy-year-old, we learned, takes three to four times as long as someone in her twenties to find and remember a mental picture linking word and location. Older adults also make more mistakes. And most important, the losses with age seem to be irreversible. …