Suppose that, seeking a fun evening out, you pay $175 for a ticket to a replacement Broadway musical.
Seated within the balcony, you quickly realize that the acting is bad, the sets are ugly and no one, you think, will head home humming the melodies.
Do you head out the door at the intermission, or stick it out for the duration? Studies of human decision-making suggest that the majority of people will stay, albeit money spent within the past logically should haven't any pertaining to the selection.
This “sunk cost fallacy,” as economists call it, is one among some ways that humans allow emotions to affect their choices, sometimes to their own detriment. But the tendency to factor past investments into decision-making is seemingly not limited to Homo sapiens.
In a study published on Thursday within the journal Science, investigators at the University of Minnesota reported that mice and rats were even as likely as humans to be influenced by sunk costs.
The longer they invested in expecting a gift — within the case of the rodents, flavored pellets; within the case of the humans, entertaining videos — the less likely they were to quit the pursuit before the delay ended.
“Whatever goes on within the humans is additionally happening within the nonhuman animals,” said A. David Redish, a professor of neuroscience at the University of Minnesota and an author of the study.
This cross-species consistency, he et al. said, suggested that in some decision-making situations, taking account of what proportion has already been invested might pay off.
“Evolution by survival wouldn't promote any behavior unless it had some — perhaps obscure — net overall benefit,” said Alex Kacelnik, a professor of behavioral ecology at Oxford, who praised the new study as “rigorous” in its methodology and “well designed.”
“If everybody does it, the reasoning goes, there must be a reason,” Dr. Kacelnik said.
Even more important than the similarity among species was the study’s finding that sunk cost effects appeared only after the themes had decided to pursue a gift, Dr. Redish noted, not while they were still deliberating whether to try to so.
In effect, the animals appeared to consider the deliberation time to not be a part of their investment — a sign, Dr. Redish said, that different brain processes could be at work in different aspects of decision-making.
The idea runs counter to the notion that “time is time, and you’re wasting it either way,” he said.
Shelly Flagel, a professor of psychiatry at the University of Michigan who was not involved in the study, said the research had “far-reaching implications across fields including education, economics, psychology, neuroscience, and psychiatry.”
For example, she said, persisting during a behavior albeit its adverse consequences are like the conduct “exhibited by people with addictions.”
“Once they begin checking out their next ‘fix,’ they're going to often go hours or days on the same quest, albeit it means abandoning food, relationships, their job,” Dr. Flagel said.
Learning more about the distinct processes that go awry in psychiatric disorders like addiction might yield new strategies for treatment, she added.
In the study, led by a doctoral student, Brian M. Sweis, three research laboratories at The University of Minnesota collaborated to conduct tests on mice, rats, and humans.
The rodents were trained to forage for the flavored pellets — banana, chocolate, grape, or plain — during a square maze with a “restaurant” in each corner.
The humans were taught to “forage” on a computer for videos of kittens, a dance competition, landscapes, or bicycle accidents.
Both rodents and humans got the overall deadline for the foraging tasks.
In the rodents’ version of the task, the animal first entered an “offer zone” outside a restaurant and heard a pitched tone that informed it how long the wait would be for the pellet reward — a delay that varied randomly from 1 to 30 seconds.
The animal could skip the offer, during which case it had been withdrawn, or it could enter the “wait for zone” of the restaurant, setting off a countdown signaled by a descending tone.
At any time during the countdown, the rodent could prefer to leave the restaurant, but once it left it couldn't return without going all the way around through the opposite restaurant offer zones.
In the human version of the experiment, subjects were offered a video and presented with buttons saying “stay” or “skip.” A download bar informed them how long they might have to wait to look at the video.
Clicking the “stay” button started a countdown and the screen showed the progression of the download.
The study found that the longer the rodents spent within the “wait zone,” the more likely they were to stay out the delay to the top, albeit the longer they waited, the more it digs their overall time to hunt food.
Similarly, the longer the human subjects spent expecting a video to download, the more likely they were to remain the course until the download was finished.
Surprisingly, the quantity of your time that the themes — rodent or human — spent deliberating whether to simply accept the “offer” of a gift didn't affect whether or not they quit before receiving it or stayed through to the top.
“Obviously, the simplest thing is as quick as possible to urge into the wait zone,” Dr. Redish said. “But nobody does that.
Somehow, all three species know that if you get into the wait for the zone, you’re getting to pay this sunk cost and that they actually spend overtime deliberating within the offer zone in order that they don’t find yourself getting stuck.”
Dr. Flagel, of the University of Michigan, noted that as compelling because the new research was, it had been not without limitations, including the very fact that the tasks presented to humans and rodents, though similar in some ways, were still quite different.
“The challenge moving forward,” Dr. Flagel said, “is getting to be to understand that one is actually capturing an equivalent phenomenon across species.
Or perhaps more appropriately, what is the meaning of the differences which will be revealed between species?”