Study: like people, mice double down on investments
by Ivan Couronne / Agence France-Presse
Economists know that when people invest time or money in something, it’s hard for them to pull out — even when their project is doomed.
Well, it turns out mice and rats seem to have the same foible, according to a study published Thursday in the US journal Science.
Economists say this involves what they call the “sunk cost” fallacy.
Say you buy tickets to a show. There is no point in going, just for the sake of going, if you decide you no longer like what it is about, say, or you are tired. Regardless of whether you go or not, you will not get your money back.
And for countries, just because lots of money has been spent on a program there is no point to keep pumping in more if it’s no longer in the national interest.
For a long time researchers have studied whether animals are like people in this regard — ferociously attached to objects just because of their past efforts with them.
Scientists at three neuroscience and psychology labs at the University of Minnesota carried out a coordinated experiment on mice, rats and humans.
Guess what happened?
“Mice, rats and humans all behaved quite similarly,” David Redish, a neuroscience professor at the university and co-author of the study, told AFP.
– Waiting for a reward –
The rodents were trained to feed in a labyrinth with four “restaurants,” one in each corner. During each trial, they arrived in a so-called “offer zone” where a tone informed them of the wait time to get something to eat — in this case flavored pellets.
If the animals accept the offer, they move on to a waiting area, where an audible countdown tells them how much longer they have to wait — from one to 30 seconds. Before all this they were trained to understand these sound signals.
For the humans a similar experiment was set up, only with videos instead of food as the lure. They could view kittens, landscapes, ballroom dancing or bike accidents.
The waiting time before they get to see the video is represented by a download bar.
In each case, the human participants could simply say no to waiting and move on to the next room or video.
The experiments showed that rodents, like people, tended to exhaust the waiting period once the wait has begun.
“The more that they stuck it out already, the more likely they are to finish,” said Redish.
It’s just like people waiting in line, he said.
“Once you get in line, you tend to stay in line. And the longer you’ve been in line, the more likely you are to finish staying in line,” Redish added.
But the wait is not cost-free because the overall duration of the experiment is restricted.
So the longer a rodent waits for its favorite pellet — say, banana or chocolate flavored — in a given room, the less total food it can munch on during the test.
Redish makes this comparison: “I’ll wait the 30 seconds for this caviar, even though truthfully, if it was five seconds it would totally be worth it.
“But standing 30 seconds for the caviar, I really ought to skip it, because I might get a five-sec potato down the line.”
The study had its limitations: it involved only 65 humans (university students), 32 mice and 32 rats. What is more, the tasks they faced were not identical. But it paves the way for more experiments.
The challenge moving forward “is going to be to know that one is truly capturing the same phenomenon across species,” Shelly Flagel, an associate professor of psychiatry at the University of Michigan who was not involved in the study, told The New York Times. (AFP)