| Except for the tails, of course. And that thing they have with cheese. |
New research on mice shows the brain processes aggressive behavior as it does other rewards. Mice sought violence, in fact, picking fights for no apparent reason other than the rewarding feeling.
| I've always found cuts, bruises, missing teeth, and the occasional shredded ear to be a rewarding feeling. |
The mouse brain is thought to be analogous to the human brain in this study, which could shed light on our fascination with brutal sports as well as our own penchant for the classic bar brawl.
| Ah, yes. Brutal sports. Y'gotta love 'em. I get so excited when the knives come out at basketball games, or when the umpire turns thumbs down at the World Series and the pitcher is shot. |
In fact, the researcher say, humans seem to crave violence just like they do sex, food or drugs.
| Like, wow, man. I'm, like, freakin' out here. I need my sex, food, and drugs! And then I'm off to the Spahn movie ranch with Susan Atkins and that Krenwinkel bitch! |
Scientists have known that mice and other animals are drawn to fights. Until now, they didn't know how the brain was involved. The new study, detailed online this week in the journal Psychopharmacology, reveals the same clusters of brain cells involved in other rewards are also behind the craving for violence. "Aggression occurs among virtually all vertebrates and is necessary to get and keep important resources such as mates, territory and food," said study team member Craig Kennedy, professor of special education and pediatrics at Vanderbilt University in Tennessee. "We have found that the reward pathway in the brain becomes engaged in response to an aggressive event and that dopamine is involved."
| So in the course of a billion or so years of evolution we've worked out that sometimes y'gotta defend your territory or someone or something else will take it over, leaving you with what the little pig got. Who'da ever guessed that? |
For the experiments, the researchers placed a pair of mice, one male and one female, in a cage. Then, the female was removed and a so-called male intruder mouse entered the cage. That triggered aggressive behavior in the resident male. The tell-tale signs of aggression included tail rattle, an aggressive sideways stance, boxing and biting.
| Classic mousie behavior involves an extended courtship marked by the male climbing on the female's back and briefly shoving her the minibaloney. Mice live about 24 months and they're ready to breed when weaned, which is at the 21-day mark. Male and female left together will breed, whether he buys flowers or not. Two males left together will fight, even if there's not a female involved. Other rodents have different levels of aggressiveness, though, and other critters have different levels than rodents -- it's common to see two male dogs or cats sharing territory, for instance. |
After the initial scuffle ended, the resident male mouse was trained to nose-poke a target to get the intruder to return. Results showed the home mouse consistently poked the target and fought with the introduced mouse, indicating, the researchers say, that the aggressive encounter was seen as a reward. "We learned from these experiments that an individual will intentionally seek out an aggressive encounter solely because they experience a rewarding sensation from it," Kennedy said.
| I'm assuming that the nose poker was the winner in the encounter and that he was letting the same opponent return for more of the same. Were the results the same when a different mouse was likely to come out of the chute, ready for a smackdown? Did they try tag teams? |
To figure out whether the brain's reward pathway was involved, the scientists treated the home mice with a drug to block dopamine in certain parts of the brain known to be involved in rewards like food and drugs. The treated mice were less likely to instigate the intruder's entry. “This shows for the first time that aggression, on its own, is motivating, and that the well-known positive reinforcer dopamine plays a critical role," Kennedy said.
| It shows that aggression is a useful behavior, which is something that 20th century ideology tried hard to demonstrate was not so. I'd say the study also puts the aggressive urge at the instictive level, which I find comforing. The theoretical establishment can try and say it ain't so all it wants, and it's still going to be so. There's a point past which conditioning won't take you. Unless you're a European, of course. |
Kennedy explained that the experiments have implications for humans. The reward pathway in the brains of humans and mice are very similar, he said. "Aggression is highly conserved in vertebrates in general and particularly in mammals," Kennedy told LiveScience. "Almost all mammals are aggressive in some way or another."
Pretty much all creatures great and small are aggressive in some way or another. Probably -- and I'm just guessing here -- salps and trilobites were, though I don't think plankton is.
Not all are the same, however. Our closest relative are a case in point: a male gorilla will usually kill the offspring of a new female. A silverback will chase off his own offspring as they reach sexual maturity, not always but based on behavior. Chimps become more aggressive with age and sexual maturity, and adolescent males form roving bands of fascisti, fighting among themselves only to about the same extent teenaged humans do. Bonobos -- pygmy chimps -- are a less aggressive strain; rather than all that fighting and strife they just try to get along, putting flowers in their fur, singing folk songs, and trading sex like hippies in a commune.
Contrary to the expectations of the ideologues, the chimps are holding their own in the wild, while the bonobo population is drifting inexorably downward -- my ultimate point being that not all creatures are equally aggressive or aggressive in the same way. |
He added, "It serves a really useful evolutionary role probably, which is you defend territory; you defend your mate; if you're a female, you defend your offspring."
| If you're researching the obvious you state it. |
Even though it served a purpose for other animals, in modern human societies, Kennedy said, a propensity toward aggression is not beneficial and can be a problem.| Right. Just ask any bonobo. Or any Dutchman. |
"The first rule of Mice Club is - you do not talk about Mice Club." |