Mice Watch Others Brawl From Perch, Learn to Fight Like Veterans, Princeton Team Reports

PRINCETON, N.J. — A team of Princeton neuroscientists reports that mice which merely watched their fellows fight developed brain patterns and combat habits resembling those of seasoned brawlers, according to an account published by The Debrief.

In the experiments, male mice were sorted into fighters, spectators and novices. Over eight days, fighters took part in three daily sessions of about ten minutes, including sparring with an easily beaten 'pushover' mouse. Spectators watched from a raised platform behind a clear barrier, able to see, hear and smell the action but not join it. Novices spent the sessions with a stuffed toy mouse and saw no fights.

On the ninth day, all three groups faced hard-to-beat opponents. Fighters and spectators alike attacked sooner than novices and spent less time with their backs turned. Senior author Annegret Falkner said the spectators did not much care about idle wandering below but would 'orient and attend' once an attack began. Lead author Jorge Iravedra-Garcia said the sequence in which the animals moved between behaviors was also quite similar. None of the groups spent more total time attacking, which the team took to mean neither fighting nor watching made the mice more violent.

Brain recordings showed a partial echo. Inhibitory cells in spectators fired in patterns 'much like a fighter's,' according to Iravedra-Garcia, though excitatory activity more closely resembled that of novices. Falkner described the spectators' brains as midway between experienced fighters and naive animals, adding that observation is not a replacement for experience. The effects also faded within days of the experiments' end.

The researchers pointed to a distant prospect of replaying recorded brain activity into inexperienced subjects, a notion the article likens to Neo's instant martial-arts training in The Matrix. Falkner suggested some of the circuit changes may be conserved between mice and humans, though the work itself was done only in mice.