As part of a study of gambling behaviour, a group of lab rats at the University of British Columbia found themselves looking down four holes.
Some of the holes offered great rewards - more sugar pellets than they knew what to do with - paired with the potential for harsh punishment in the form of imposed "time outs" that removed them from the game for long stretches. The other holes offered moderation, with less possibility of punishment, but also lesser rewards.
So did they take the gamble? According to UBC psychology assistant professor Catharine Winstanley, the rats couldn't resist at least trying the far riskier option; but eventually, they figured out the optimal strategy - going for smaller gains and smaller penalties - and stuck to it.
In another gambling simulation, the rats played "slot machines" - that is, they would press a lever that would make a series of lights turn on or off. If all the lights came on, the rats could collect a windfall of sugar pellets; if all of the lights were off, but they still tried to collect a prize, they would be "punished" by being temporarily removed from the game.
What's interesting is that the rats seemed to have trouble differentiating between wins and near-misses - where two of the three lights were lit - which may help to explain what keeps rats, and by extension humans, pushing those levers.
"We can justify all kinds of behaviour that's bad for us if rats are doing the same thing," jokes Ms. Winstanley, who hopes the findings will help them develop medications for people with gambling disorders. "It implies there are actually some very old evolutionary signals that our brains are generating, and that we're responding and reacting to." Jennifer Van Evra