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Belief in Change Reduces Bullying

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Teen sitting in hallway with head down


Rejection by peers leads teens to act aggressively and feel down.


Teaching teens that everyone has the capacity to change decreases aggression and symptoms of depression following peer exclusion. If people can change, so too can social labels like “bully” and “loser."


Developmental psychologist David Yeager and his colleagues recruited 246 9th and 10th graders from a high school with frequent student conflicts. Yeager randomly assigned students to one of three 6-session workshops in which students would supposedly mentor incoming 9th graders.

In the change is possible condition, students first learned effort and experience shape the brain, and so everyone has the potential to change. Students practiced applying this mindset to their own peer conflicts. Later sessions addressed students’ common questions such as, “Is it my responsibility to change others?” Finally, students cemented their understanding by writing letters to future 9th graders expressing the importance of their newfound mindset.

In the coping skills condition, students learned standard methods for managing conflicts and then practiced applying these strategies to their own experiences. Students wrote letters to future 9th graders about their successful coping strategies.

In the no-treatment (control) condition, students received no intervention.

One month later, students played an online game of catch (“Cyberball”) in which they were led to believe that a peer was excluding them from the game. Immediately afterward, the researchers measured aggression by giving students an opportunity to allocate hot sauce to the peer who had excluded them (and who had said they didn’t like spicy food). The students also had a chance to write a note to the peer.

Following the experience of “Cyberball” exclusion, students in the change is possible condition responded less aggressively: they allocated fewer grams of hot sauce than did students in the coping skills and no-treatment conditions. Students in the change is possible condition also wrote kinder letters. Both students in the change is possible and coping skills conditions had fewer symptoms of depression than did students in the no-treatment condition.

Yeager also assessed students’ aggressive behavior 3 months later. Students in the change is possible condition displayed less misconduct at school than did students in the coping skills and no-treatment conditions.

This study reveals that mindsets matter: Brief sessions that change beliefs about the malleability of personality can protect teens from rejection’s negative effects (i.e., aggression and symptoms of depression).

Why This Works

When teens believe people can change, they realize labels like “bullies” and “losers” are only temporary. This belief empowers teens to try to change their situation by responding kindly, as opposed to aggressively, to peers who exclude them. Understanding that social labels can change also helps teens feel less depressed about rejection.

When This Works Best

This intervention works best with people who believe that personalities are fixed and people can’t change. In addition, this intervention most helps people who regularly experience exclusion because they have more opportunities to practice their new skill—that is, responding kindly to rejecting people.

The Original Study

Yeager, D. S., Trzesniewski, K. H., & Dweck, C. S. (2013). An implicit theories of personality intervention reduces adolescent aggression in response to victimization and exclusion. Child Development, 84(3), 970–88.

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Related Topics

Conflict Resolution Criminal Justice Education


Text by Christina Chwyl.

Photo CC by Lee Morley.