Study Finds Monkeys Believe in Following Winning Streaks

Posted on: July 1, 2014, 05:30h. 

Last updated on: July 1, 2014, 03:34h.

Rhesus monkey, monkey study, winning streaks
Rhesus monkeys in a recent study apparently believed in winning streaks, although this one looks like he is telling his buddy the inevitable bad beat story. (Image:

If you believe that you should always bet on the numbers that are hot at the roulette table, then you might be happy to hear you’re not alone in your belief in the “hot hand” fallacy. New research shows that the belief that random events are following a pattern is far more widespread than previously believed. To be fair, though, these new subjects would probably say they have faith in their hot paw instead.

A new study from the University of Rochester found that rhesus monkeys share what was thought to be a very human belief in hot hands, or the idea that a bet that has been paying off, will continue to do so. The research, led by doctoral candidate Tommy Blanchard, has added evidence that finding patterns in random data may be an evolutionarily inherited trait, rather than one we pick up from the culture around us.

Monkeys Play Simple Guessing Game

In order to study how monkeys thought about gambling, researchers created a fast-paced computerized game in which the subjects simply guessed whether the winning side would be left or right. If they were correct, they would receive a reward. This was enough to keep the monkeys playing for hours on end.

“Luckily, monkeys love to gamble,” Blanchard said.

The researchers then made the game play in one of three ways. Sometimes, the game would actually hand out rewards at random, with no pattern whatsoever. Other times, the wins would tend to be on one side. Finally, there was a version in which the winning side usually alternated from left to right.

When the game had one of the pattern sequences, the three monkeys in the study quickly figured them out and started winning their rewards. But in the random games, the monkeys instead continued to try to find patterns, favoring one side in the expectation that recent streaks would continue. This behavior didn’t change with experience, either: it kept happening for weeks and thousands of trials.

“They had lots and lots of opportunities to get over this bias, to learn and change, and yet they continued to show the same tendency,” Blanchard said.

A Shared Bias Towards Pattern Recognition

While the study wasn’t a perfect analogue for gambling, as the monkeys did not have to risk anything to earn their rewards, it still made it clear that their brains have the same tendency as human beings to find patterns, even when there are none. Researchers believe that this is likely tied into how primate brains developed to find food in the wild, a very non-random process in which pattern recognition is key.

“If you find a nice juicy beetle on the underside of a log, this is pretty good evidence that there might be a beetle in a similar location nearby,” said Benjamin Hayden, a coauthor of the study. “We have this incredible drive to see patterns in the world, and we also have this incredible drive to learn…if there’s a pattern there, we’re on top of it. And if there may or may not be a pattern there, that’s even more interesting.”

As in other studies of this type, it is hoped that the research can help aid in the treatment of problem gambling, as this addiction is often exacerbated by gambling-related fallacies.