Conscientious Adults: Then and Now If our unexpected discovery about childhood conscientiousness and its relevance to long life is not a fluke, then we should also be able to find confirming evidence by studying conscientious adults.
Almost two decades after starting, in the summer of 1940, Dr. Terman approached Patricia and the other members of his select study again. He gave them an extensive new series of tests and measures with such questions as “Are you thrifty and careful about making loans?” and “How persistent are you in the accomplishment of your ends?” From these results we worked for months to construct and validate a new series of personality scales. At times, we also incorporated similar questions that Terman asked the participants in 1950.
Studies of health across the life span face an intriguing dilemma. In order to see whether personality in childhood and young adulthood predicts long life, a result that can’t be seen until decades later, we necessarily need to use “old” data. In our case, information from the early and mid-twentieth century is being used to predict longevity into the twenty-first century. But years later, new, improved measures are in vogue, and the dusty old measures and techniques are likely subject to criticism. As Dale Carnegie put it, “Any fool can criticize, condemn and complain, and most fools do.”
Short of time travel, how can we be sure that the measures we have from the 1920s, 1940s, and 1950s reflect what we understand about personality today? What at first seemed simple gradually became more and more complex. We decided to administer the Terman questionnaire items to a contemporary sample of people. More than a half century after Dr. Terman measured the personality of Patricia at thirty years old, we recruited a new group of young adults in California and asked them the exact same questions. We also recruited a sample of parents to rate their young children on Terman’s scales, just as parents of the Terman participants had done in the 1920s.
We then gave these new participants some modern, well-validated personality tests. Through a series of statistical analyses, we were able to check the old data against new data, thereby creating valid, modern personality measures for Patricia and her associates. It was almost as if we had gone back decades and measured Jess Oppenheimer’s personality by finding a modern-day doppelganger. We did this in the technical, statistical way, and then, just to be sure, we examined all the scale items in a rational, commonsense manner. Fortunately, all of the data analyses fit together quite well.7 Dr. Terman’s approach to personality holds up nicely and can help us predict our own futures.
Doing the right statistical analyses in such attempts to predict long life is much more difficult than might be imagined. Long-term longitudinal studies are especially challenging because participants come and go, rejoin or drop out, disappear or are discovered, and live or die. In addressing these and related statistical issues, we were fortunate to have Professor Joseph Schwartz as a key research collaborator. Joe has one of best analytic minds in this field.
Revenge of the Virtuous
Conscientiousness, which was the best predictor of longevity when measured in childhood, also turned out to be the best personality predictor of long life when measured in adulthood. The young adults who were thrifty, persistent, detail oriented, and responsible lived the longest. Patricia was one of these, having told Dr. Terman that she enjoyed “planning [her] work in detail” and tended to “drive [herself] steadily.” When asked about how she typically pursued goals, she indicated that she was persistent and that she had “definite purposes.” Patricia also reported being “thrifty and careful about making loans” and not at all impulsive. In fact, she had done very well in college and was expecting to have a highly successful career.
By the end of the twentieth century, 70 percent of the Terman men and 51 percent of the Terman women had died. It was the unconscientious among them who had been dying in especially large numbers. This confirmation in adulthood was particularly impressive because personality was being measured differently. Conscientiousness in childhood was measured by parent and teacher ratings. Conscientiousness in adulthood was measured by self-report questionnaires—our analyses of how participants described themselves and their activities. In both cases—childhood and adulthood—conscientiousness was the key personality predictor of long life.
Why Do the Conscientious Stay Healthier and Live Longer?
We thought of three possible reasons for why conscientious individuals tend to stay healthier and live longer. To our great surprise, all three are true. The first reason, perhaps most obvious, is that conscientious people do more things to protect their health and engage in fewer activities that are risky. They are less likely to smoke, drink to excess, abuse drugs, or drive too fast. They are more likely to wear seat belts and follow doctors’ orders. They are not necessarily risk averse but they tend to be sensible in evaluating how far to push the envelope.
The second, and least obvious, reason for the health benefits of conscientiousness is that some people are biologically predisposed to be both more conscientious and healthier. Not only do they tend to avoid violent deaths and illnesses linked to smoking and drinking, but conscientious individuals are less prone to a whole host of diseases, not just those caused by dangerous habits. We and others are uncovering this startling finding again and again—conscientious folks are less likely to die from all sorts of causes. While we are not yet sure of the precise physiological reasons, it appears likely that conscientious and unconscientious people have different levels of certain chemicals in their brains, including serotonin. Serotonin is the neurotransmitter targeted by antidepressant drugs like Prozac, Paxil, and Zoloft. Individuals with low levels of serotonin tend to be much more impulsive. Importantly, serotonin is also necessary to regulate many health-relevant processes throughout the body, including how much you eat and how well you sleep.
This is no cause for fatalism, however. Neurotransmitter levels can change over time, and being biologically predisposed toward certain physiological processes is not a death sentence any more than being predisposed to depression means you will absolutely fail to thrive and find satisfaction in life. As we will see, some Terman subjects who started out low on conscientiousness (i.e., who were impetuous and impulsive children) led long and healthy lives.
We’ve saved the best for last. The most intriguing reason conscientious people live longer is that having a conscientious personality leads you into healthier situations and relationships. In other words, it is not only that conscientious people have better health habits and healthier brains, but also that they find their way to happier marriages, better friendships, and healthier work situations. That’s right, conscientious people create healthy, long-life pathways for themselves.
In and Out of Conscientiousness
Some people do change, and they travel down a path that leads them far away from the habits of their youth—for good or for ill. While we found a consistent link between dependable kids and their future adult selves, we also confirmed that human beings can be inconsistent creatures. Some wild frat boys quit drinking the morning after their fortieth birthday. Cautious others abandon their sensible lifestyle in midlife and buy a red sports convertible. How is a change in long-term conscientiousness relevant to health?
We decided (with the advice of Dr. Joe Schwartz) to compare four kinds of people:
- The first is someone like Patricia who was highly conscientious (in the top quartile) in both childhood and adulthood.
- The second is an individual who was conscientious in childhood but turned unconscientious by adulthood.
- The third is someone, such as the tactful and charismatic James, who was decidedly low on this trait as a kid but became one of the most conscientious subjects by the time he reached young adulthood.
- The fourth kind was unconscientious in childhood and remained so in adulthood.
We found that those Terman participants who scored high at both points in time had the lowest risk of dying at any given age. Those who scored low at both points in time had the highest risk of dying. And the others, those who had changed their level of conscientiousness, were in between.
Does It Generalize?
The nineteenth-century Lithuanian scholar Yisroel Lipkin (known as Rav Yisroel Salanter) reportedly said that three things can be learned from a train: (a) if you’re late a minute you can miss it, (b) even a tiny move off the tracks causes a catastrophe, and (c) if you travel without a ticket you get punished.9 We do not have a conscientiousness score for Mr. Lipkin, but staying on track with the proper tickets does seem to be an excellent metaphor for a conscientious lifestyle.
But how can we be sure that conscientiousness is as important to us in the twenty-first century as it was to Dr. Terman’s subjects (or to Rabbi Lipkin, for that matter)? Our highly conscientious and talented recent graduate student (and now Ph.D.) Margaret (Peggy) Kern addressed this question. Peggy knew that the past decade had seen a number of researchers following up on our findings and conducting many excellent new studies on personality and health. Why not gather them together and combine the results using the statistical technique called meta-analysis?
Although meta-analysis sounds like a Kantian proposition or a therapy for aging Freudians, it is really a fairly straightforward mathematical tool to combine the results of many studies into a single summary. Peggy computer-searched for all the studies ever published that included a conscientiousness-related trait—prudence, responsibility, self-control, or impulsivity—and a measure of longevity. She found twenty studies, with a total of about nine thousand participants. We combined those studies, and the results clearly confirmed our Terman findings—people ranking higher in conscientiousness were less likely to die at any given age.10 This held true for young people and it held true for sixty-five- to one-hundred-year-olds.
Personality and Chronic Disease
Conscientiousness predicts long life, but what about its relevance to serious chronic disease? Surely other factors matter quite a bit—would they override the importance of conscientiousness? What about diseases like diabetes, hypertension, stroke, lumbago, depression, and bladder disease? Could prudence possibly be relevant?
We teamed up with Columbia University epidemiologist Renee Goodwin and looked at a nationally representative sample of thousands of Americans, in order to draw from a large body of evidence in a modern national study. As we now expected, unconscientious people were more likely to suffer from each of these chronic conditions. Individuals who measured low on conscientiousness were not only more likely to be clinically depressed, feel anxious, smoke cigarettes, and have high blood pressure and sciatica, but they were also more likely to have tuberculosis, diabetes, joint problems, and strokes.
Of course, many different things contribute to health and longevity: brushing your teeth and being perennially punctual are not the same as discovering the fountain of youth and drinking its dancing waters of healing. We knew this was not the end of our work on personality and health. We needed to know a great deal more about how conscientiousness combined with other traits and pathways to lead to better health and longer life. The surprising and paradoxical findings about cheerfulness, worrying, sociability, and other characteristics are in the pages ahead.
What It Means for You: Guideposts to Health and Long Life
Are conscientious and dependable people also boring and stale? We have found absolutely no evidence for this stereotype. Potential astronauts and military leaders who are slackers and screwballs are generally not the ones launched into space or put in charge of army commands. The careless and sloppy among us are not the ones usually selected to be judges and surgeons and heads of our most esteemed institutions. Many of the most conscientious Terman subjects led exciting and highly rewarding lives.
Conscientious, dependable people stay healthier and live longer. This is not always the case—there are many exceptions to be found—but conscientiousness is a very good predictor. If you are a conscientious person, the news is good—keep doing what you are already doing. If you are like Patricia, your habits, brain biochemistry, and social environment are likely to work together to decrease your risk of poor health and early death. You’re at much lower risk of becoming seriously ill, and you probably already worry enough about health-relevant habits and activities. But large numbers of people are not so conscientious. If this describes you, are you doomed?
No, but you’re not likely to change your personality or lifestyle rapidly. It doesn’t matter how many New Year’s resolutions you make. In fact, rapid and pervasive changes are usually quickly abandoned by anyone undertaking them. Lasting adjustments happen with smaller, but progressive, steps.
People can and do slowly change their patterns and their habits when they seek out situations that promote responsibility. For James, the transition took nearly a decade. In 1922 his conscientiousness score was in the lowest 25 percent of participants. His mother and schoolteacher described him as vain and noted that he lived wholly in the present, seeming never to look very far ahead. He wasn’t always reliable or truthful, either, according to these important adults in his life. Smart, like all of the subjects, James finished his freshman year of college at the age of seventeen, but he seemed bored by school and was performing far below his abilities. He took a year off (accomplishing little during that time) but at his family’s urging he returned to college and, after switching majors twice, finally graduated with a degree in communications.
When James was assessed in 1936 he was working steadily in public relations and had recently gotten married. We have hints from his family about his characteristics in early adulthood—his mother said he had money worries and his wife described him as a nonconformist, but not as impulsive. By the 1940 assessment, however, his conscientiousness score had moved into the upper 25 percent. He liked his work and was now more detail oriented and persistent and had definite goals. He was still somewhat vain, but James’s personality profile as he moved into midlife was much more prudent than it had been in his youth. And he survived to a seasoned old age.
James did not become more conscientious overnight. Based on what our data tell us, it is clear that as James gradually took on the responsibilities of a mature adult, he adopted more and more healthy habits. Yes, he maintained and even increased his physical activity, but that by itself wasn’t the key to his longevity. What mattered most was that he entered healthier social environments and relationships, which in turn fostered his health. As we will see in later chapters, his marriage was a good one (his wife agreed), and although his job in public relations wasn’t highly technical or exotic, he took pride in doing it very well. As an adult, he described himself as an honest person of high integrity. These new habits and relationships, paralleling his slow alteration in personality, provided a solid foundation for James’s health and long life. The next puzzle for us to solve would be why James succeeded in this way while others headed down more destructive paths.
