Scientists’ Mouse Fight Club Demonstrates the Home Field Advantage

By Andrew Moseman | July 6, 2010 4:45 pm

lab_miceIt feels good to win. And it feels even better to win at home.

For a new study in the Proceedings of the National Academy of Sciences, Matthew Fuxjager and his colleagues investigated the winner effect, wherein animals (and perhaps humans) build up testosterone in advance of a confrontation, and the fight’s winner maintains that elevated level. By studying male mice fighting one another, Fuxjager was able to see what happens in the brains of winners. Not only did victorious mice experience the “winner effect,” but those who won at home—in their own cages—saw the most activity, and wanted to keep on fighting.

To get these results, Fuxjager’s team essentially created a tournament of mouse fights.

One challenge they faced was ensuring the right mice won the right fights. They got around this by borrowing a trick from seedy boxing promoters the world over, pairing the favored mouse with a weaker, less sexually experienced opponent who could not hope to spring an upset. Once a mouse had notched three consecutive victories, they studied its brains for any chemical changes [io9].

In the brains of winning mice, they saw an uptick in the hormonal expression in regions that govern aggression. And in the brains of mice who won at “home,” they saw something else.

In addition, “home-win” mice showed increased androgen sensitivity in regions that mediate motivation and reward. These mice also won more subsequent fights compared to mice who’d only come out in away fights [New Scientist].

While the winner effect might help mice defend their territory in the wild, it’s not always good—especially when it comes to humans. When DISCOVER spoke to John Coates about the neuroscience of the financial collapse, he suggested that the effect could have something to do with the high-risk behavior of Wall Street traders. Once testosterone levels reach the point where performance peaks, any continued increase starts to override our judgment—and those sub-prime mortgage bundles begin to look more and more tempting.

Related Content:
DISCOVER: Could “Hormonal Diversity” Help Prevent Another Meltdown?
80beats: Does Testosterone Make Trusting Women More Skeptical?
80beats: Does Testosterone Cause Greedy Behavior? Or Do We Just Think It Does?
Not Exactly Rocket Science: Testosterone-Fueled Traders Make Higher Profits

Image: Wikimedia Commons

  • Mary

    This must have been an interesting IACUC approval…

  • Jack C.

    vivisectors curing diseases again…who funded this abusive busywork?

  • Josh

    Mediating aggression is a super important goal for humanity. If a bunch of mice have to die to enable us to get valuable information about the neural pathways for aggression, then so be it.

  • JR

    Humans do more to continue the proliferation of aggression and violence by abusing, enslaving and objectifying animals or any minority group that has less power than another. Tests like these are ignorant of the obvious; a culture that condones all of the above and tests like these in the name of science or otherwise will only empower those who believe it is okay to disregard the value and interests of others for their own interest or amusement. Besides if these “scientists” want to do some hard, intelligent work and not earn their ridiculous salaries for torturing individuals, they should maybe try talking to people with the issues they are are trying to solve instead of playing with mice. Then again, they are trying to maintain the status-quo from about 400 years ago.

  • Hastaroth

    If a bunch of “Josh” have to die to enable us to get valuable information about the neural pathways for aggression,then so be it.

    After all,the “Josh” are humans,they will die with their own consent-writen and informed.Mice,on the other hand,are neither informed nor consenting to their death for the interests of humans.

  • Mousketeer

    1-Every site I have seen talking about this experiment sensationalizes it by talking about a “fight club.” It wasn’t a fight club. It put two territorial mice in a cage and they did what they do, determined who’s space it was. Since it is what they do naturally and they weren’t instigated into fighting, it follows IACUC guidelines.
    2- No vivesection took place. Observations were made, and the mice were put to sleep like we do with a loved pet, and then they had their brains examined for lasting changes to their specific receptors. Vivesection is a loaded word bandied about by people who are against animal experimentation, and I respect their views, but it is used far too often to describe things that are not vivesection (live cutting.)
    3- What is the status quo from 400 years ago they are trying to maintain? Ignorance? and who with aggression issues is going to tell an experimenter that they have an increased sensitivity to androgens in the medial anterior bed nucleus of their stria terminalis which is making them more aggressive, and every time they are more aggressive it happens again? All you would hear is “that guy looked at me funny so I had to break his face. It felt good, so I beat his friend for being there.” Self report does not work for this.
    5- I am non-violent, I do not condone animal cruelty, and I have questions about the usefulness of lots of the experiments that are taking place all over the world… but not this one.

  •,29507 Tani hosting

    Hmm is anyone else encountering problems with the pictures on this blog loading? I’m trying to find out if its a problem on my end or if it’s the blog. Any responses would be greatly appreciated.

  • Casey Marie Raasumaa Rollins

    It’s articles like these that make scientists who use animals in their studies look bad. I highly doubt that the IACUC application they submitted was titled “Rat Fight Club.” If you are reporting on a serious subject, why not fucking act like it and report facts as they are, and not with a stupid juvenile twist to make it cute.


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