Research Hit: Dopamine and Aggression
New research shows that dopamine promotes aggressiveness - in male novice fighters only - in mice that is.
I thought dopamine was linked to reward - such as the now well-known dopamine hit of social media?
Yes, that is the simplistic view but as I keep saying: everything in the brain is always way more complex and nuanced than popular posts suggest.
I do, by the way, review dopamine briefly here.
Dopamine is involved in much more than reward, actually it is not really a reward transmitter - but being involved in aggression is new to me also.
So what was this research?
This was research into mice - yes the good ‘ole mouse again. But still fascinating. Mice, like many animals, protect their territory and male mice can get aggressive and fight other males who encroach on their “pad”.
Bing Dai and colleagues of New York University gave male mice a boost in dopamine and these then became more aggressive, fighting for twice as long as they normally would. Blocking dopamine stopped them fighting altogether. But interestingly boosting dopamine in female mice had no impact on their aggressiveness.
But what about testosterone - I thought that made males more aggressive?
Yes, that is what a lot of people think - but here it is also more nuanced. Testosterone (short review here) seems to only boost aggression in those who are already aggressive. Testosterone can also boost cuddling behaviour as I reported here!
But this is also in line with what we know about dopamine - namely that it is a key motivational transmitter and also drives attention and learning.
But there was also a difference between “novice” and “experienced” fighters.
Oh really!
Yes, this effect was only present in novice fighters i.e. young mice who had little previous aggressive contact.
In older mice who had a history of defending their territory, and fighting with other mice, dopamine didn’t exert an influence.
Sounds surprising but it is again in line with dopamine as a learning and focusing agent - if you already have the experience it may not exert an effect. Although, I would have thought that there would have been a small effect.
They also, I note, found the area that contributes to this aggressiveness: an area called the lateral septum, in case you’re interested. This is a well-connected area sitting deep in the brain.
So when we say “dopamine hit” this may be literal
Yes, it gives us a greater understanding of aggression but also of the role of dopamine.
Reference
Dai, B., Zheng, B., Dai, X. et al.
Experience-dependent dopamine modulation of male aggression.
Nature (2025).
https://doi.org/10.1038/s41586-024-08459-w