Implicit person theory determines whether you notice change. Carol Dweck sorted people into two camps. Entity theorists believe personality stays fixed. Incremental theorists believe people change. Across 5 studies, entity theorists drew stronger trait inferences from a single behavior (Source: Chiu, Hong and Dweck, Journal of Personality and Social Psychology, 1997, Pub Peer).

Across 5 experiments, the same belief predicted stronger stereotyping (Source: Levy, Stroessner and Dweck, Journal of Personality and Social Psychology, 1998, Stonybrook).

The workplace cost shows up in reviews. In 4 studies, fixed-belief managers anchored ratings to first impressions and missed real improvement (Source: Heslin, Latham and VandeWalle, Journal of Applied Psychology, 2005, Papers).

A short self-persuasion workshop shifted those managers. The shift held for 6 weeks (Source: same). As 2026 year-end review cycles open, managers get a concrete check. Rate the last six months of work, not the first week.

“You know how he is”

Quick Summary: Early workplace mistakes harden into durable reputations among coworkers. Teammates repeat an opening-week verdict after six months of strong client results. Carol Dweck’s entity theory explains why a single label keeps outlasting every piece of evidence against it.

A new coworker joins your team. Three days in, he emails a client and gets her name wrong in the greeting. By Friday, he walks into the team meeting twenty minutes late.

Then six months go by.

He now runs that client’s account better than anyone else on the team. He hasn’t missed a deadline. Still, the next time something slips, somebody shrugs and says, “Well, you know how he is.”

Everybody nods. Everybody thinks they know. A wrong name and a late Friday got filed somewhere, and twenty-six weeks of good work never pulled the file.

Plenty of people believe that people don’t change. If they’re right, his first week tells you everything you need. If they’re wrong, what has the team been holding onto all this time?

Entity theory vs. incremental theory

Quick Summary: Entity theorists treat personality as settled. Incremental theorists treat personality as movable. A short agreement survey sorts adults into either camp (Source: Dweck, Chiu and Hong, Psychological Inquiry, 1995, HKU).

Psychologist Carol Dweck found that most people lean one way or the other without realizing it. Some assume personality stays put. You can learn new skills, but a person’s core doesn’t change. Dweck called this an entity theory.

Others assume people can change in real ways over time. She called that an incremental theory.

Researchers sort people with a short survey. You rate how much you agree with statements like “people can’t really change their deepest traits.” The survey asks only general questions, with no scenarios attached. The surprise comes when researchers see that one belief shapes how people judge each other.

One act, and suddenly a whole character

Quick Summary: Fixed-belief readers convert one act into a lasting trait. They forecast that trait across unrelated settings. Malleable-belief readers request more evidence first (Source: Chiu, Hong and Dweck, 1997).

In 1997, Chi-yue Chiu, Ying-yi Hong and Carol Dweck gave people short descriptions of someone’s behavior. Sometimes a description covered a single act. Then they asked what kind of person it suggested, and how that person would act in other situations.

People with fixed beliefs jumped the farthest. From one honest act, they decided the person had an honest character. They predicted honest behavior in situations unrelated to the first one.

People who believed in change made smaller predictions. Often they wanted more information before deciding anything.

Psychologists have a name for that habit. Lee Ross and Richard Nisbett called it lay dispositionism, our everyday tendency to explain people by their traits instead of their situations.

Sound familiar? It works a lot like the fundamental attribution error, where we turn an act into a trait. Believing traits stay fixed just lowers the bar. You need less evidence to reach the same verdict.

Fourth-graders do it too: implicit theories in children

Quick Summary: Fourth- and fifth-graders showed the same split. Fixed-belief children labeled a struggling new boy “bad.” Change-minded children described his nerves and proposed help (Source: Erdley and Dweck, Child Development, 1993, OUP).

Dweck found the same pattern in kids. In 1993, she and Cynthia Erdley showed fourth- and fifth-graders a slideshow about a new boy at school. He wanted to make friends. As the story went on, he lied and broke a few rules to impress the other kids.

Then the researchers asked the kids about him. Kids with fixed beliefs called him bad or mean. They expected him to keep acting that way and recommended more punishment.

Kids who believed people change watched a different boy. They talked about how nervous he must have felt at a new school. They suggested someone help him so he could make friends more easily.

Same slideshow. Two different boys.

From one person to a whole group

Quick Summary: Fixed beliefs extend from individuals to groups. Entity theorists endorsed familiar stereotypes more strongly. They also built stereotypes about invented groups from few examples (Source: Levy, Stroessner and Dweck, 1998).

People with fixed beliefs don’t stop at one person. In 1998, Sheri Levy, Steven Stroessner, and Carol Dweck tested whether that belief shapes how people see groups. Fixed-belief participants agreed more with common stereotypes. After reading just a few examples about made-up groups, they also formed stronger stereotypes about them.

Picture a diner who decides his server was careless. If he holds a fixed belief, the verdict doesn’t stay at his table. It follows him to the next restaurant and lands on the next server, too.

Why first impressions stick in performance reviews

Quick Summary: Fixed-belief managers anchor appraisals on early observations. Those anchors suppress credit for later improvement. A brief self-persuasion workshop corrected the anchoring (Source: Heslin, Latham and VandeWalle, 2005).

This research hits closest to home for me. It also explains why I don’t like performance reviews.

In 2005, Peter Heslin, Gary Latham, and Don VandeWalle had managers watch videos of an employee whose performance changed over time. In some videos, the employee improved; in others, the work slipped.

Managers with fixed beliefs struggled to see the change. Their ratings stuck close to their first impression.

That pull has a name too. The researchers called it anchoring, where the first thing you see sets the starting point for every judgment after it.

If the employee started weak, the rating stayed low even as the work improved. Managers who believed people change noticed the improvement and raised their ratings.

Then the researchers tried something else. They ran a short workshop to nudge managers with fixed beliefs toward believing people can change. Afterward, those managers noticed improvement more, and the shift held six weeks later. Their ratings reflected the actual work rather than the first impression.

Now go back to the new coworker. A fixed-belief manager carries that wrong client name into every review. Six months of improvement shows up, and it barely moves the number.

The belief points back at you: the end-of-history illusion

Quick Summary: Adults underestimate how much they will change. Researchers named this pattern the end-of-history illusion. That self-view spills onto colleagues (Source: Quoidbach, Gilbert and Wilson, Science, 2013, Science)

People tend to project their own beliefs onto others. You don’t hold one belief while everyone else holds another. Dweck’s survey sorts all of us, and you get sorted too.

So if you believe you’ve finished changing, you probably assume everyone else has, too. Psychologists call this the end-of-history illusion. In 2013, Jordi Quoidbach, Daniel Gilbert and Timothy Wilson asked adults of all ages to look back and look ahead. People of every age expected to change less over the next decade than they had over the last.

So do people actually change? In 2006, Brent Roberts, Kate Walton and Wolfgang Viechtbauer pooled 92 longitudinal samples covering ages 10 to 101. Personality traits kept shifting through adulthood, middle age, and old age. A 2022 update led by Wiebke Bleidorn found the shifts slightly smaller than first estimated. Small still counts as movement.

I’ve done this myself. When I kept clashing with one coworker, I labeled him “insecure,” and that one word turned into his whole description. I’d frozen him in the same notebook where I kept my own views, the ones I treated as finished.

Before your next review

Pick one person at work you’ve summed up in a single word. Write down the moment that first earned them the word, with a rough date. Then write down one thing they did this past month.

Put the two lines side by side. Which one have you been grading?

Questions and Answers