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Kids Can Be Cruel. But Why?The Science Behind Bullying

Updated: Sep 8, 2022

It was a typical Wednesday at work this past week. The emails were flowing in faster than I could read them and I was lost in thought as I tried to solve the problem of how to make a credit card page flow better. I’d only just shared with my co-workers, that I’d published the first Milo book when an unexpected message popped up in my email from a co-worker:

I heard you wrote a book Jenna and I wanted to let you know that my son is struggling. He’s not like other kids in his class. He’s not being bullied quite yet, but my other son was and it was awful. I’m going to buy your book. I’m hoping it can help. You know how cruel kids can be.”

I was overjoyed that she’d taken the time to read the book reviews on Amazon and that she’d taken a leap of faith in using Milo to help her son embrace who he is despite his peers’ reaction. But the last sentence of her message made me pause. I’d often thought about this notion of cruelty over the years, both as a clinical psychology graduate student and someone who worked directly with children and families. Can children really be considered cruel? If they can, is there scientific support to explain why? Let’s examine this for a moment.


As children are developing, their ability to perceive their physical reality as well as empathize with others is also developing. It’s why I thought at age four that I could jump off my bed and truly fly. Or why my sister told me to stick my finger in our night light socket and nothing too terrible would happen to me. P.S. it didn’t. Not really. Though, I did learn not to mess with my sister that day. And maybe we both learned that the physical reality of the world was slightly different than what we saw in cartoons. Was it mean spirited that my sister lied to me and told me it would feel good to stick my finger in the socket knowing she’d left the light night plugged into the wall? Sure. But was it cruel? No. In her developing brain, there weren’t real or long-lasting consequences to her actions and as soon as I cried out in pain, she realized what she’d done. Even if she set out to play a prank she didn’t get any pleasure out of seeing me in pain. Children who can empathize with others’ pain are the ones least likely to bully and hurt other children on purpose.

But empathy isn’t something we’re necessarily born with. Early childhood development specialists believe that children begin to learn how to empathize over the first three years of life. If there is any developmental trauma, the chances of a child being able to feel or demonstrate empathy can be compromised. Of course, not every child who has difficulty empathizing has developmental trauma. Some children with other diagnoses such as ADHD and those on the autism spectrum also have challenges with empathy. Ultimately, though, there are tangible ways to teach children how to empathize with others and to feel a sense of connection to all beings.

Impulse Control + Dopamine=Bullying

Another important factor in understanding bullying has to do with the aggression circuitry in the brain. Inside of our brains we have a home for where we allow an impulse to be inhibited or activated called our prefrontal cortex. And the home for where our emotions and impulses live is in our limbic system. In a perfect world, the circuitry between these two would allow us to decide when we act aggressively and in which circumstances. But, unfortunately some people have weaker connections. According to neuroscientist, R. Douglas Fields, “animals and people with weaker connections from the prefrontal cortex to the limbic system encounter difficulties with impulse control.”(R. Douglas, 2019) Besides the impulse control factor, Fields also explores the rewarding aspect of aggression. He points to evidence that aggression over others enables a person to feel superior and dominant and underlies what he calls “the hedonistic component of bullying." What this means is that bullies may experience an increase of dopamine in their brain’s reward center. I know, scary. But, the science behind aggression helps answer the age old question of why kids can be cruel. The good news is a child’s brain is still developing. There is still hope for them to learn empathy and impulse control.

With that said, I am not glossing over the pain bullies cause other children. One child’s dopamine hit and lack of impulse control is another’s pain and humiliation. If only knowing how the human brain works could eliminate the unpredictability of human behavior. And I can’t turn to my co-worker and tell her all about the neocortex and expect that to take away how much emotional pain her child is in. That would be completely tone deaf on my part and incredibly insensitive. And of course, completely out of character for me. But, it is empowering for a lot of people to have a better handle on why it might be happening to their child.

My Personal Journey

Besides the facts and echoing the latest research surrounding bullying, it is also something I have direct experience with (as many of you know). Both my twin sister and I experienced it throughout our childhood. So, on an emotional level I truly get the pain it causes and how helpless I felt being the direct victim of it and also a passive victim watching my twin sister go through it. Maybe this is partly why I’ve felt compelled to get my hands on every piece of information I can over the years and why I am so dedicated to teaching children resilience.

And here’s the heart of it really—empathy. Because I have first-hand experience with bullying I have an even greater level of empathy. Had I not been bullied or watched my sister go through it I might be sensitive to the pain of others, but not fully aware of the mark it leaves. So although I can forgive those who hurt me, I can’t forget the little girl within me who cried many a night wanting desperately to fit in. Who hoped one day she could be taller, more developed, and maybe even have money like the rest of the kids in her class so she wouldn’t have to wear hand me downs and get teased by the neighborhood kids whom donated those clothes.

But, here’s the thing. I am not unique. My experience is universal because we all walk away from our childhoods with invisible marks, beliefs, and sometimes scars. And many of us also walk away with one key job—to heal as adults. Just like so many others, it has been my job to heal this child within me so that I can, all of these years later, create Milo, Anton, Polly and an entire cast of characters who in return are helping other children heal. Through the Milo books children learn how to develop the internal resources towards wholeness, self-love, compassion, and endurance because one little girl (that’s me) decided once upon a time to never give up, to have faith in herself, to believe in the goodness of people and to never stop “cartwheeling”. This can be the legacy of bullying. There is the science of course behind it, but there is also something unquantifiable too—the human spirit and hope.

With love,


P.S. If you want to learn more about ways to keep your child safe online here's a great resource from Consumer Notice.


Fields, Douglas R. The Roots of Human Aggression [The Scientific American]. Retrieved from

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