Ever wonder why anti-vaxxers, climate change deniers and even people who think Earth is flat stick to their beliefs in the face of overwhelming evidence to the contrary?
New findings from US researchers suggest that feedback, rather than hard evidence, boosts people's sense of certainty when learning new things or trying to tell right from wrong.
Developmental psychologists have found that people's beliefs are more likely to be reinforced by the positive or negative reactions they receive in response to an opinion, task or interaction, than by logic, reasoning and scientific data.
Their findings shed new light on how people handle information that challenges their worldview, and how certain learning habits can limit one's intellectual horizons.
"If you think you know a lot about something, even though you don't, you're less likely to be curious enough to explore the topic further, and will fail to learn how little you know," said study lead author Louis Marti, a PhD student at the University of California.
This cognitive dynamic could play out in all walks of actual and virtual life, including social media and cable-news echo chambers, and might explain why some people are easily duped by charlatans.
"If you use a crazy theory to make a correct prediction a couple of times, you can get stuck in that belief and may not be as interested in gathering more information," co-author Assistant Professor Celeste Kidd said.
Specifically, the study examined what influences people's certainty while learning.
It found that study participants' confidence was based on their most recent performance rather than long-term cumulative results.
For the study, more than 500 adults, recruited online through Amazon's Mechanical Turk crowdsourcing platform, looked at different combinations of coloured shapes on their computer screens.
They were asked to identify which coloured shapes qualified as a "Daxxy" - a make-believe object invented by the researchers for the purpose of the experiment.
With no clues about the defining characteristics of a Daxxy, study participants had to guess blindly which items constituted a Daxxy as they viewed 24 different coloured shapes and received feedback on whether they had guessed right or wrong.
After each guess, they reported on whether or not they were certain of their answer.
The final results showed that participants consistently based their certainty on whether they had correctly identified a Daxxy during the last four or five guesses instead of all the information they had gathered throughout.
"What we found interesting is that they could get the first 19 guesses in a row wrong, but if they got the last five right, they felt very confident," Marti said.
"It's not that they weren't paying attention, they were learning what a Daxxy was, but they weren't using most of what they learned to inform their certainty."
An ideal learner's certainty would be based on the observations amassed over time as well as the feedback, Marti said.
"If your goal is to arrive at the truth, the strategy of using your most recent feedback, rather than all of the data you've accumulated, is not a great tactic."
You're most like 'you' in a time-crunch
When they must act quickly, selfish people are likely to act more selfishly than usual.
That's according to a US study that also found the opposite was true when it came to people inclined to help others.
"People start off with a bias of whether it is best to be selfish or pro-social," explained study leader Assistant Professor Ian Krajbich, of Ohio State University.
"If they are rushed, they'll tend to go with that bias."
But when people have more time to decide, they were more likely to go against their bias as they evaluate the options in front of them.
The study involved 102 college students from the United States and Germany who played 200 rounds of a game that is often used in psychology and economics experiments.
In each round, played on a computer, the participants chose between two ways of splitting up a real sum of money.
Both choices favoured the person playing the game, but one choice shared more of the money with the unseen partner.
"The participants had to decide whether to give up some of their own money to increase the other person's payoff and reduce the inequality between them," Krajbich said.
The decision scenarios were very different.
In some cases, the participants would have to give up only, say, $1 to increase their partner's payoff by $10.
In others, they might have to give up $1 to give their partner an extra $1.
And in other cases, they would have to make a large sacrifice - for example, give up $10 to give their partner an extra $3.
The key to this study was that participants didn't always have the same amount of time to decide, Krajbich said.
In some cases, participants had to decide within two seconds how they would share their money as opposed to other cases, when they were forced to wait at least 10 seconds before deciding.
And in additional scenarios, they were free to choose at their own pace, which was usually more than two seconds but less than 10.
The researchers used a model of the "normal" decisions to predict how a participant's decisions would change under time pressure and time delay.
"We found that time pressure tends to magnify the predisposition that people already have, whether it is to be selfish or pro-social," Krajbich said.
"Under time pressure, when you have very little time to decide, you're going to lean more heavily than usual on your predisposition or bias of how to act."