How Beliefs About the Self Shape Personality and Behavior

Stanford University psychologist Carol Dweck tells the story of Barbara Herbert and Daphne Goodship, identical twins who were separated at birth and adopted into different families, completely unaware of each other’s existence. When they were reunited at age 39, both Barbara and Daphne were wearing beige dresses and brown velvet jackets. What’s more, they both had the eccentric habit of pushing up their nose, and they both giggled more than anyone else they knew.

People are fascinated by separated-at-birth stories like these, and behavioral geneticists have marshaled such colorful detail as evidence of inborn personality traits. In addition to eccentricities, identical twins often also share aspects of temperament, like sociability and self-control. But in her keynote address at the APS 19th Annual Convention, APS Fellow Dweck emphasized that much about personality and behavior is demonstrably not part of a fixed genetic legacy. Specifically, Dweck argues that beliefs about the self and the world not only contribute to and change personality, they underlie adaptive functioning in school, work, and relationships.

Dweck described her work on “mindsets” and their influence on academic performance. People tend to hold one of two beliefs about intelligence: Some believe that intelligence is a fixed entity, endowed at birth and unchanging, whereas others believe that intelligence is malleable. People with these different “self theories” tend to have very different experiences in life. Those with a fixed mindset set as their primary goal in life the documentation of their ability, not true learning. When they experience setbacks, they take these setbacks as reflections of their innate ability, becoming defensive and helpless. By contrast, people with a malleable mindset value learning and growth and react to adversity with increased effort and strategies for change. They are resilient.

Dweck has demonstrated the power of belief in many studies, including one (with Jennifer Mangels) in which she measured the brain-waves of students with different mindsets. She gave the students a computerized test, deliberately made up of very difficult questions. Exactly 1.5 seconds after the students answered a question, the computer told them if they answered correctly or incorrectly. Exactly 1.5 seconds after that, the computer gave the correct answer. Dweck measured the electrical activity of the students’ brains to see when in this process the students focused their attention. The students with a fixed mindset basically stopped paying attention once they knew if they were right or wrong: “Their work was over,” Dweck said. Those with a malleable mindset — and a belief in effort — were more focused on learning the real answer.

Dweck also has shown that it’s possible to intervene and change beliefs. Even those with a tendency to think of fixed ability can learn otherwise — with effects on performance. She (with Lisa Blackwell and Kali Trzesniewski ) studied a group of junior high school students whose math grades were declining steeply. All of the students had eight sessions of training in study skills, except that for half the students, these sessions included instruction in the malleability of intelligence. They were told that the brain is a muscle, which like other muscles can be strengthened with hard work. The students were “mesmerized,” she says, by the idea that they had the power to grow and enrich their own brains. The result? The students who learned the malleable mindset theory rebounded with better math grades, and their teachers reported positive changes in their motivation. (Dweck designed a computer software version of this intervention, called “Brainology,” which is now being tested in 20 New York City schools.)

Beliefs can also affect relationships, Dweck reported. Her research (with Susan Johnson) builds on the work of John Bowlby, who theorized that infants form internal models of relationships with other human beings based on their early experiences. Dweck and her colleagues studied 12- to 16-month-old children who were either securely or insecurely attached to their mothers. They had them watch a story, using abstract shapes, in which the “mother” moves away from the “child,” who follows. When all of the children had gotten used to this story through many viewings, the story ended in one of two ways: Either the mother returned to care for the child, or she continued on her way, effectively abandoning the child. The secure children expressed more interest and surprise at the abandonment than did the insecure children; indeed the insecure children, if anything, were more surprised by the caring mother’s behavior.

Such beliefs about security and relationships can manifest themselves in adult relationships as well, Dweck says. Adults with low expectations and anxiety about relationships have more fragmented and shorter-lived romantic relationships. They are more apt to perceive rejection in ordinary thoughtless behavior of their partners and respond in ways that undermine the relationship (e.g., with jealousy, hostility, passive-aggressiveness). Such insecure adults are also less involved and do less well in social interactions in general. They have learned through experience certain beliefs about others, and those beliefs have shaped their attitudes and behavior in crucial ways.

These kinds of beliefs can be changed as well. Dweck reported research by Greg Walton and Geoff Cohen in which African-American students who were entering college were taught to expect acceptance rather than rejection from others. They learned that doubts about being accepted in this new environment were common but largely unwarranted. Students receiving this information, compared to those in a control group, were more likely to reach out to professors, participate in class discussion, study more, and earn higher grades.

Dweck concluded that perhaps it was inevitable that the identical twins Barbara Herbert and Daphne Goodship would both giggle a lot. But it is not inevitable in many, many cases that people must function poorly in important areas of their lives: “Beliefs matter. Beliefs can be changed. And when they are, so too is personality.”