Brain Rules for Aging Well. John Medina
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toxic isolation, that’s like stagnant water to a mosquito.
On top of that, the nature of friendship is changing. The digital world provides enticing electronic substitutes for flesh-and-blood interactions. An intense research effort is under way to see if this matters, and I’ll have more to say about it in a later chapter.
The bottom line: environmental forces put seniors at greater risk for being alone than ever before. That’s noxious, for at a time when your brain is already under corrosive assault from Darwinian-approved natural causes, social isolation is the last thing it needs.
And that’s not even the full story. Nature plays just as strong a role as nurture. It is to these ideas that we next turn.
Face time
Prosopagnosia. It’s tough to pronounce, tougher to experience. People who suffer from the P-word aren’t able to do something even infants can do: recognize faces. They may have known you for years, but they won’t recognize you if you walk into the room five minutes from now. Nor will they recognize anybody else, even though they usually can recognize every thing else. No problem with hats, for example, or with eyebrows, or even with the concept of “face.”
Sufferers of prosopagnosia (logically called face blindness) usually resort to extraordinary measures to navigate their social world. A person might have to memorize the clothes their family members regularly wear in order to tell them apart. Others might have to pay close attention to the way people move or to specific postures, in order to recognize people at work. The late neurologist Oliver Sacks, a famous sufferer of face blindness, would have his guests wear name tags at parties so he could recognize them.
Not surprisingly, many people with the disorder withdraw socially, often suffering from social anxiety. This makes a certain amount of sense, for a great deal of social information is carried by the face. Clues to whether someone is happy or sad, contented or disgusted, potential mate or potential threat, show up in the eyes, cheeks, and jowls. Without the knowledge of what someone is feeling, sufferers withdraw into a Twilight Zone world where people can recognize you but you can’t return the favor. Sacks himself quit attending conferences and large parties.
Prosopagnosia is associated with lesions in a brain region called the fusiform gyrus, an area in the lower part of your brain not far from where your spinal column enters your skull. Strokes and various head traumas can damage the fusiform gyrus. Face blindness also is as heritable as eye color, which means you can get it from your parents. It is thought to affect about 2 percent of the population. But a less severe form of it seems to be related to normal aging as well.
As people get older, they suffer an increasing inability to recognize familiar faces, and they lose their perception of some of the emotional information those faces carry. We even know the reason. The neural tracts—the white-matter cabling—connecting the fusiform gyrus to other regions of the brain begin to lose structural integrity. Prosopagnosia illustrates an important principle in the brain sciences: specific regions of the brain exert a dictatorship over specific functions. When those regions become injured, those functions can be altered—or disappear.
The behavioral deficits are not global. Seniors can recognize emotions like surprise, happiness, and even disgust just fine (in fact, they score better on tests measuring disgust than younger adults do). Not so with sadness, fear, and anger. It’s an unfortunate twofer: seniors have a harder time recognizing people they know, sort of like a mini-prosopagnosia, and they have a harder time recognizing certain feelings those people are experiencing.
Do seniors withdraw socially as a result of these deficits, similarly to people with face blindness? Though there is (always) the need for further research, the answer may be yes. As we discussed, people begin to withdraw from social interactions as they age (remember the peak at twenty-five and downward slope at fifty-five?). Seniors show an especially severe reduction. Interestingly, the same shrinkage in social activity occurs in lab-raised monkeys when they become elderly.
We’ve talked about mentalizing, or Theory of Mind. As you get older, the ability to mentalize begins to decline. In a lab assay called the “false belief task,” people try to guess the intention of someone else. Younger adults routinely get the correct answer about 95 percent of the time, elderly adults about 85 percent of the time. The senior scores worsen with age, such that after age eighty, the scores shrink to less than 70 percent. The reason appears to be an age-related change in the functional activity of a single region in the prefrontal cortex. The prefrontal cortex (often abbreviated as PFC) is evolution’s newest add-on to your brain’s fundamental architecture. It’s a most talented structure, with functions ranging from decision making to personality formation. As we’ll discover later, most of the talents we identify as uniquely human arise in the PFC.
Is it possible that changes in facial recognition and changes in mentalizing ability are related? And if so, might they be part of nature’s contribution to the social isolation experienced by many of our elderly? The real answer is we don’t know. But the fact that I can write about this stuff in a scientifically meaningful fashion at all represents a tremendous leap in our understanding from even a few years ago. Such progress has even bled into the practical realm of intervention. Solid research shows steps we can take to ameliorate the negative effects of loneliness. It is to these steps that we turn next.
Dance the night away
The years of age separating dancers Mikhail Baryshnikov and Fred Astaire span about a half century. No matter: the Latvian’s admiration for his American colleague is evident. “No dancer can watch Fred Astaire and not know that we all should have been in another business,” said the legendary Soviet and American ballet dancer. He was describing the Hollywood movie star and legendary hoofer, who danced with just about every leading lady in twentieth-century American film, and also with brooms, rotating rooms, firecrackers, even his own shadow. He inspired a whole generation of Americans to get out there and dance the night away, with a chain of franchisable dance studios trumpeting the cause. As a brain scientist, watching his seemingly effortless movements, I say he should inspire us again. Unfortunately, he died in 1987, at the ripe old age of eighty-eight.
The reason for my enthusiasm is scientific. You can cover the dance floor with peer-reviewed papers showing the benefits of this regular, ritualized movement that forces social interaction. The scientific benefits are almost too good to be true.
Consider one study, where researchers enrolled healthy older adults, ages sixty to ninety-four, in a six-month dance class, one hour per week. The investigators assessed a broad range of cognitive and motor skills before class commenced, then assessed them again six months later. Non-dancing controls were also measured.
The results were as welcome as free tickets to the Bolshoi. Hand-motor coordination (as measured by a standardized Reaction Time Analysis assay) improved by about 8 percent in six months. That might not sound like much, until you consider that the scores of the controls actually decreased during the same period. Suites of cognitive skills were tested, including fluid intelligence, short-term memory, and impulse control. These increased by an impressive 13 percent during the dance class. Posture and balance (measured by using the so-called forced-platform test) increased by about 25 percent in the dancers over their previous scores. And again, the nondancers showed a net decrease. Half a year later, the dancers did not move the same way—or think the same way.
The type of dance didn’t seem to matter. Tango, jazz, salsa, folk, various kinds of ballroom dancing: all exerted their whirling wizardry on the brain. Further research has shown that other forms of ritualized movement instruction, such as tai chi and various martial arts, also show benefits in many of these same measures.
One of the most unexpected findings had to do with the number of falls experienced by seniors who took movement classes. During the testing period in one tai chi program, the number of falls fell by 37 percent. Falling is not a trivial issue for the elderly, and for the two reasons they care the most about: head injuries and bank accounts. In the United States, medical expenses from seniors’ falls total more than $30 billion a year. In Australia, fall-related injuries among the elderly take nearly 5 percent of the health care budget.
Fred