Aging neurons, cultural pressures, historical conditions, and past education all affect adult cognition. None of these can be controlled directly by an individual. Nonetheless, many researchers believe that each adult has the power to make crucial choices about his or her intellectual development.

For example, if adults decided to discard their calculators, their math skills might improve. Of course, most adults would consider that strange: Spending more time on math might help number intelligence, but few modern adults want to do double-digit division in their heads.

Similarly, memory would improve if a person never relied on their smart phone or e-mail to reach their friends. Are modern cultural artifacts making us lazy intellectually, or have we merely focused on new challenges? The answer may be both.

A theme of the first half of this chapter is that choices and perceptions affect adult health. That applies to intellectual development as well. As you have seen, adult IQ is variable, sometimes increasing and sometimes falling. We now look at some factors that influence this, a combination of individual choices and social pressures.

Many health decisions that adults make, as seen earlier in this chapter, prioritize immediate comfort over long-term health. Choices of foods, drugs, exercise, and health care affect cognition because anything that slows down blood circulation in the body also slows down the brain. That affects speed of thought and leads to brain shrinkage.

Moreover, harmful choices increase stress, which impairs brain functioning (Prenderville et al., 2015). Stress does not merely correlate with illness of all kinds—it causes illness, as hundreds of studies on the immune system and stressors have found.

Sometimes people are told “it’s all in your head” when they complain of physical ailments. That is neither fair nor accurate. A recent comparison between stress-free adults and adults who were caring for a family member with brain cancer found that the caregivers had signaling factors in their brains that increased expression of genes for inflammation. Thus, basic immunity is affected when stress is high (G. Miller et al., 2014). As in this case, caregiving may be the expression of basic values. For many people, no other option is possible.

Chronic stress increases depression and other psychological illnesses that impair thinking, and it attacks the brain itself (Marin et al., 2011; McEwen & Gianaros, 2011). The psychological disorder posttraumatic stress disorder (PTSD) is recognized as harming a person long after an initial trauma. Avoiding all stress is impossible, but people can choose to reduce stress, reinterpreting problems that arise, and to care for themselves so that coping is easier.

THE STRESS OF MODERN LIFE All the demands of modern life increase the stress on each adult. Some of those stresses become stressors. A stressor is an experience, circumstance, or condition that affects a person. Thus, a stress is external; some stresses are internalized, becoming stressors.

Drug abuse, obesity, lack of exercise, cigarette smoking, high-fat diets, uncontrolled diabetes, avoiding medication to control hypertension—all chosen by many adults—impair thought. Are such choices a reaction to the demands and pace of current life? Was life simpler when it was shorter?

Perhaps adults must cope with more stressors than was true earlier, although certainly some stresses are reduced. Deaths in war and revenge for crimes are decreasing (Pinker, 2011), so fewer people must cope with a premature death of a parent or child. However, the rate and scope of disasters—caused by human and natural events—is increasing. That causes multiple stresses in survivors (Leaning & Guha-Sapir, 2013).

To be specific, the World Health Organization defines disasters as unexpected events—both from nature (floods, earthquakes, and so on) and from nurture (bombs, epidemics)—that cause at least 10 deaths and 100 serious injuries. The rate in the first decade of the twenty-first century was ten times that of a century ago and three times the rate 20 years earlier (Leaning & Guha-Sapir, 2013).

Moreover, globalization and high-speed communication networks mean that each disaster adds stress to millions far from the event—think of television footage of 9/11, or Hurricane Katrina, or the bombings of Gaza, Yemen, Syria. Research finds that when people watch immediate coverage of disasters, that increases acute stress reactions to later disasters—even for people far from the trauma and personally unaffected (Garfin et al., 2015).

In addition, personal events that are stressful—divorce, intellectual disabilities, relocation, immigration, job loss—are more common than they were, so every adult experiences major stress. Finally, every life has many minor stresses called hassles—traffic jams, noise at night, rude strangers, computer breakdowns—that trouble many adults.

COPING Throughout history adults have used various ways to cope with stress. Some of these are effective; others are not.

The worst coping is avoidant coping, which averts dealing with the problem. All the bad habits described earlier in the chapter—drug use, overeating, underexercising—temporarily relieve anxiety but eventually make things worse. Ignoring a problem, either literally forgetting it via a drug-induced blackout or hiding it (one person who owed back taxes threw all official letters under his bed, unopened) is the worst response to stress—it increases depression and the risk of suicide.

Avoidant reactions cause yet more stressors. An effective way to gain perspective on stress is to help other people, yet some people in avoidant coping isolate themselves. For instance, parents of disabled children need help from each other and from relatives, but such parents have higher rates of divorce than the average parent. Similarly, some people diagnosed with serious illness do not tell their friends, some LGBTQ (lesbian, gay, bisexual, transgender, questioning) individuals stay “in the closet,” some people with serious addictions hide from other people.

Psychologists distinguish two positive strategies. In problem-focused coping, people attack the stressor directly—for instance, confronting a difficult boss, moving out of a noisy neighborhood, helping community members caught in the same earthquake, donating money, or food, or blood (as millions of Americans did after 9/11). The other way to cope is with emotion-focused coping, changing their emotional reactions—for instance, from anger to acceptance, from resentment to understanding. This mode of coping is one form of the cognitive coping, mentioned in Chapter 8, as well as the positivity effect that seems to occur in late adulthood.

Of course, natural disasters, such as earthquakes, and personal tragedies, such as the death of a loved one, are always stressful immediately and cannot be erased. However, reinterpretation may be possible. Instead of dwelling on their misfortune, they emphasize their good fortune—not “why me?” but “it could have been worse.” The stresses are seen as a challenge, even when outsiders would consider them threats (Reich et al., 2010).

For example, although Hurricane Katrina occurred years ago, survivors continue to cope with the aftermath, and social scientists continue to study them. One team considered religious beliefs before and after the disaster. Victims who believed in a vengeful and punishing God continued to suffer, but those who believed that God is caring and benevolent coped well, experiencing posttraumatic growth, not PTSD (posttraumatic stress disorder) (Chan & Rhodes, 2013).

This study confirms a general trend. Some people use religion to cope with stress, especially when unexpected illness or disaster occurs (in the United States, church attendance was up after 9/11), which may either bring solace or make things worse (Burke et al., 2013; Thuné-Boyle et al., 2013).

Are there gender differences in preferred coping styles? Men may be problem-focused, reacting with “fight or flight.” Their sympathetic nervous system (faster heart rate, increased adrenaline) prepares them for attack or escape. Testosterone rises when men confront a problem and decreases if they fail. From childhood, males are encouraged to express anger, use force (fight), or disappear (flight).

Females, however, may be emotion-focused, likely to “tend and befriend”—that is, to seek the company of other people when they are under pressure. Their bodies produce oxytocin, a hormone that leads them to seek confidential and caring interactions (S. Taylor, 2006; S. Taylor et al., 2000). Their first reaction when something goes wrong might be to call a friend. A woman might be troubled if a man won’t talk about his problems; a man might get upset if a woman does not take his advice and solve her problems.

This distinction appeared among 634 mothers and fathers who had lost a baby, either stillborn at birth or dying within the first days and months of life (D. Christiansen et al., 2014). The women were more likely to anxiously seek social support from other people (sometimes overprotecting another child), and men were more likely to avoid attachment (sometimes spending hours away from home).

Gender differences should not be exaggerated. Both problem- and emotion-focused coping can be effective; everyone should sometimes fight and sometimes befriend. In the study of bereaved parents, the researchers noted that both parents sometimes suffered from PTSD and suggested that they could help each other (D. Christiansen et al., 2014). A review suggests that gender differences, including fight-or-flight versus tend-and-befriend responses, are much smaller in reality than in popular assumptions (Carothers & Reis, 2013).

CHOOSING METHODS Not only do adults of both sexes need to find the best strategy for each particular problem, but they also need to decide who will help, how and when (Aldwin, 2009). Getting social support is generally a good strategy—other people provide suggestions, lighten a load, and add humor or perspective (Fiori & Denckla, 2012). But sometimes other people criticize, distract, or delay a person’s coping.

Related to social support is the overall social context, which may diminish stress or may increase it. A U.S. study of 65,000 adults compared biomedical signs of poor health, such as hypertension and insulin resistance, which collectively are called weathering. In this study, weathering happened faster among African Americans—by age 60 their average biological age was 10 years older than that of European Americans.

One explanation is that something within African Americans (their genes? their diet? their personal coping style?) causes faster weathering. However, the authors of this study blame the “chronic stress” of living in a “race-conscious society” (Geronimus et al., 2006, p. 832). Another study of White, Black, and Hispanic adults in Chicago pinpointed the correlation between hypertension and vigilance, i.e., being chronically on the alert for discrimination (Hicken et al., 2014).

Ideally, with age and experience adults learn to respond wisely, and social supports are in place so that trauma—from the televised accounts of distant wars to the daily hassles of living in a crime-ridden neighborhood—does not wear down resilience. Hopefully, maturity reduces stress. As described in Chapter 15, over the years of adulthood, a more positive attitude toward life develops, making it easier to reinterpret stresses so that they do not fester.

Paul and Margret Baltes (1990) developed a theory called selective optimization with compensation to describe the “general process of systematic functioning” (P. Baltes, 2003, p. 25). They believe that people seek to optimize their development, selecting the best way to compensate for physical and cognitive losses, becoming more proficient at activities they want to perform well and deciding to avoid other tasks.

Selective optimization with compensation applies to every aspect of life, from choosing friends to playing baseball. Each adult seeks to maximize gains and minimize losses, practicing some abilities and ignoring others. Such choices are critical, because any ability can be enhanced or diminished, depending on how, when, and why a person uses it. It is possible to “teach an old dog new tricks,” but adults need to choose to learn those new tricks.

Research on adult cognition finds that, when adults are motivated, few age-related deficits are apparent. However, compared with younger adults, older adults are less motivated to put forth their best effort when the task at hand is not particularly engaging (Hess et al., 2009). That works against them if they take an IQ test.

As Baltes and Baltes (1990) explain, selective optimization means that each adult selects certain aspects of intelligence to optimize and neglects the rest. If the ignored aspects happen to be the ones measured on intelligence tests, then IQ scores will fall, even if the adult’s selection improves (optimizes) other aspects of intellect. The brain is plastic over the life span, developing new dendrites and activation sequences, adjusting to whatever the person chooses to learn (Karmiloff-Smith, 2010).

For example, suppose someone is highly motivated to learn about a particular area of the world, perhaps East Timor, a tiny independent nation since 2002. That someone goes to the library, selecting key articles and the two dozens books in English about East Timor, ignoring other interesting topics (selection).

Then suppose that aging vision makes it hard to read the fine print of some news articles about East Timor. Time for compensation—new glasses, a magnifier, increased font size. Some bits of knowledge may be pivotal: Note-taking strategies may include color coding and underlining to emphasize crucial facts. The result: if a local lawmaker or history buff wants to know about genocide, or Indonesia, or the United Nations, then that someone can provide valuable knowledge about East Timor that few others have (optimization).

If the expert on East Timor takes an IQ test that includes tamarind as a vocabulary word, that person might score high in vocabulary but fail questions of general knowledge. Thus, knowledge increases in depth but decreases in breadth.

Another way to describe gains and losses, or selective optimization with compensation, is to say that every adult is an expert in something. Each adult specializes in whatever is personally meaningful, anything from car repair to gourmet cooking, from illness diagnosis to fly fishing. One of my students said she was an expert in makeup; she always looked beautiful.

As people develop expertise in some areas, they pay less attention to others. For example, everyone watches only a few television channels or none at all, ignoring vast realms of experience. Each person has no interest in attending certain events for which others wait in line for hours. I wish my beautiful student had wanted to be an expert in developmental psychology, but adulthood has taught me that my passions are not shared by everyone.

Culture and context guide us in selecting areas of expertise. Many adults born 60 years ago are much better than more recent cohorts at penmanship, which was taught by their teachers in childhood. Those students practiced, became experts, and now maintain expertise.

Today’s adults make other choices for children. Reading, for instance, is currently considered crucial, unlike a century ago when adult illiteracy was common. Parents buy blocks with letters on them for babies and read books to toddlers. Teachers and parents are pleased when kindergartners can read, unlike 50 years ago when reading began in first grade. Schools are closed down if too many third-graders are poor readers; states brag about their reading proficiency scores—and do not pay attention to penmanship.

Experts, as cognitive scientists define them, are not necessarily people with rare and outstanding proficiency. Nor are they simply people who are competent at a particular skill (Tracey et al., 2014). Although sometimes the term expert connotes an extraordinary genius, to researchers it means more—and less—than that. Expertise is not innate, although people with inherited abilities often select those abilities to develop. Experts are more intuitive, automatic, strategic, and flexible in their chosen field, as now explained.

INTUITIVE Novices follow formal procedures and rules. Experts rely more on past experiences and immediate contexts; their actions are therefore more intuitive and less stereotypic than those of the novice. The role of experience and intuition is evident in every vocation, from surgeons to musicians, from teachers to truck drivers.

One study compared psychotherapists, both experienced and new—all with the requisite academic knowledge. The therapists were asked to talk aloud as they analyzed a hypothetical case. The experts did more “forward thinking,” using inferences and developing a possible treatment plan. The novices were less likely to think about the social relationships of the person and more likely to stick to describing what is rather than wondering what might be (Eells et al., 2011).

This conclusion needs to be qualified, however. A review of expertise and therapy found that, although they generally improve the lives of their clients, few therapists become genuine experts. Needed is more feedback and readjustment based on the eventual outcomes of their clients—an application of the scientific method (Tracey et al., 2014). Expertise develops best when learning is ongoing; intuition needs to be tempered by data on success.

An experiment involved 486 Dutch college students, asked to predict the winners of four World Cup soccer matches soon to be played. The students who were avid fans (the experts) made better predictions when they had two minutes of unconscious thought (when they could not think about soccer because they had to solve a difficult math problem) than when they had time to mull over their choice (see Figure 12.7).

Those who didn’t care much about soccer (the nonexperts) did poorly overall, but they did worse when they had time to use unconscious intuition (Dijksterhuis et al., 2009). Intuition works for experts, but not for others.

AUTOMATIC This experiment with soccer experts and nonexperts also confirms that many elements of expert performance are automatic; that is, the complex, time-consuming action and thought required by most people have become routine for experts. Experts process incoming information quickly, analyze it efficiently, and then act in well-rehearsed ways that make their efforts appear unconscious. In fact, some automatic actions are no longer accessible to the conscious mind.

This is apparent if you have tried to teach someone to drive. Excellent drivers who are inexperienced instructors do not recognize or verbalize automatic knowledge—such as scanning the far side of the road for pedestrians and cyclists, or feeling the car shift gears as it heads up an incline, or hearing the tires lose traction on a bit of sand. Yet such factors differentiate the expert from the novice.

This may explain why, despite powerful motivation, quicker reactions, accurate knowledge of road rules, and better vision, teenagers’ rate of fatal car accidents is three times that of adults (Insurance Institute, 2012). Sometimes they take risks (speeding, running a red light, drinking, and so on), but often they simply misjudge and misperceive conditions that a more experienced driver would automatically notice.

The same gap between knowledge and instruction occurs when a computer expert tries to teach a novice what to do, as I know myself when my daughters try to help me with the finer points of Excel. They are unable to verbalize what they know, although they can do it very well on my computer. It is much easier to click the mouse or do the keystroke oneself than to teach someone else what has become automatic.

The fact that such skill is automatic, not the result of increased motivation or practice, was evident in EEGs of the brain activity in musicians and non-musicians when they heard music (Rigoulot et al., 2015). All were instructed to listen for a target sound within the music, and they all tried their best, with some of both groups succeeding. But automaticity was apparent: The brains of the musicians responded more rapidly and robustly as soon as the music started.

Automatic processing is thought to explain why expert chess and Go players are much better than novices. They see a configuration of game pieces and automatically encode it as a whole, rather than analyzing it bit by bit. A study of expert chess players (aged 17 to 81) found minor age-related declines, but expertise was much more important than age (Jastrzembski et al., 2006).

This was particularly apparent for speedy recognition that the king was threatened: Older experts did that in a fraction of a second, almost as quickly as younger adults who knew the game well, despite the elders’ steep, age-related declines on standard tests of memory and speed (Jastrzembski et al., 2006).

When something—such as an audience, an unfamiliar place, or too much conscious thought—interferes with automatic processing, the result may be clumsy performance. This is thought to be the problem when some experienced athletes “choke under pressure”—their automatic actions are hijacked (DeCaro et al., 2011).

STRATEGIC Experts have more and better strategies, especially when problems are unexpected. Indeed, strategy may be the most pivotal difference between a skilled and an unskilled person, as the skilled person has sufficient experience to be able to have alternate strategies available when new problems arise.

Determining how people choose strategies is a complex question (Marewski & Schooler, 2011), and it is difficult to compare experts and novices except to note that experience prevents panic. Expert chess players have general strategies for winning and dozens of specific strategies that prevent quitting too readily, or continuing to play when checkmate is inevitable (Bilalić et al., 2009).

Scientists seek to understand the variations and origins of cognitive strategies needed to sort through the many bits of information that are accumulated over the years. Experts use their cognitive reserve (a special form of organ reserve) to develop appropriate strategies (Barulli & Stern, 2013).

Expertise has been demonstrated in the following areas: “computer programing, chess playing, teaching . . . playing bridge, solving algebra word problems, solving economic problems, and judicial decision making” (Tracey et al., 2014, p. 220). Considering those, you can see that effective strategies are essential—no one could be proficient at, for example, solving algebra word problems without a good method, far beyond good calculating skills.

Another example, familiar to everyone, is teaching. Think about your most expert professor. He or she institutes routines and policies early in the semester, which are strategies for avoiding problems later. If a sudden student outburst occurs, the expert calms the student and uses that to teach; the novice professor might be unnerved and make things worse.

FLEXIBLE Finally, perhaps because they are intuitive, automatic, and strategic, experts are also flexible. The expert artist, musician, or scientist is creative and curious, deliberately experimenting and enjoying the challenge when unexpected things occur (Csikszentmihalyi, 2013). Remember Pavlov (Chapter 1). He already had won the Nobel Prize when he noticed his dogs’ unexpected reaction to being fed. His expertise made him notice, then investigate, and eventually develop insights that opened a new perspective in psychology.

Experts in all walks of life adapt to individual cases and exceptions—much as an expert chef will adjust ingredients, temperature, technique, and timing as a dish develops, tasting to see whether a little more spice is needed, seldom following a recipe exactly. Standards are high: Some chefs throw food in the garbage rather than present a dish that many nonexperts would happily serve. Expert athletes, mechanics, and musicians are similarly flexible, able to tailor their responses to nuances that escape the novice.

In the field of education, best practices for the educator emphasize flexibility and strategy, as each group of students has distinct and often erroneous assumptions. It is not helpful to simply teach the right answers; flexibility requires matching the instruction to the individual students, discovering what learning is needed (Ford & Yore, 2012).

A review of expertise finds that flexibility includes understanding which particular skills are necessary to become an expert in each profession. For example, repeated practice is needed in typing, sports, and games; collaboration skills are needed for leadership; and task management strategies are needed for aviation (Morrow et al., 2009). Practice is not merely rote repetition; it must be deliberate, allowing learning from experience (Ericsson, 2006).

EXPERTISE AND AGE The relationship between age and expertise is not straightforward. Much depends on the task: The young have an advantage when speed is needed, but they are less adept at vocabulary. Further, they have less experience, which may be crucial for some tasks, and they have had less time to practice—-although some teenagers practice day and night at music, or math, or something else and become quite expert in early adulthood.

An interesting example of age and practice comes from perfumers. For that profession, an acute sense of smell is essential as they seek to develop new scents. Usually the sense of smell is reduced with age, but this does not seem true for perfumers. One study found that older experts outdid younger nonexperts at detecting smells, because parts of the professionals’ brains were better developed for smell (Delon-Martin et al., 2013).

This illustrates a general conclusion from research on cognitive plasticity: Experienced adults often use selective optimization with compensation, becoming expert. This is apparent in many workplaces. The best employees may be the older, more experienced ones—if they are motivated to do their best.

Complicated work requires more cognitive practice and expertise than routine work; as a result, such work may have intellectual benefits for the workers themselves. In the Seattle Longitudinal Study, the cognitive demands of the occupations of more than 500 workers were measured, including the complexities involved in the interactions with other people, with things, and with data. In all three occupational challenges, older workers maintained their intellectual prowess (Schaie, 2005/2013).

One final example of the relationship between age and job effectiveness comes from an occupation familiar to all of us: driving a taxi. In major cities, taxi drivers must find the best route (factoring in traffic, construction, time of day, and many other details). They also must know where and when new passengers are likely to be and who wants to talk, who wants silence, and how to respond when the passenger has opinions the driver finds narrow and wrong. Expert drivers earn far more in tips than novices; they have learned from experience.

Research in England—where taxi drivers “have to learn the layout of 25,000 streets in London and the locations of thousands of places of interest, and pass stringent examinations” (Woollett et al., 2009, p. 1407)—found not only that the drivers became more expert with time but also that their brains adjusted to the need for particular knowledge. In fact, some regions of their brains (areas dedicated to spatial representation) were far more extensive and active than those of an average person (Woollett et al., 2009). On ordinary IQ tests, the taxi drivers’ scores were average, but in navigating London, expertise was apparent.

Other studies also show that people become more expert, and their brains adapt, as they practice various skills (Park & Reuter-Lorenz, 2009). This development occurs not only for motor skills—playing the violin, dancing, driving a taxi—but also for logic and other reasoning skills (Zatorre et al., 2012). The human brain is plastic lifelong, as new learning is always possible and practice is crucial.

Now we return to Jenny, who left my office decades ago. As I wrote, she came to me because I am an expert in human development, but over the years I have realized that her expertise regarding her life contexts was far ahead of mine.