- Researchers found that seeing someone yawn makes people more alert to threats
- A previous study found that seeing yawns increased people’s ability to detect snakes.
The reason we yawn has long been a mystery.
But it could be because it helps us avoid harm, a study suggests.
Researchers found that seeing someone yawn makes people more alert to threats.
It is believed that yawning evolved as a signal to the group that one of them is tired. A bystander’s brain becomes more alert to threats to cover for the tired (and therefore more vulnerable) member of the group.
“The group vigilance hypothesis proposes that seeing someone yawn should trigger neurocognitive changes to enhance the observer’s vigilance as a means of compensating for the yawner’s reduced alertness,” the SUNY Polytechnic Institute researchers said.
It is believed that yawning evolved as a signal to the group that one of them is tired, alerting other people.
“The tendency to be attuned to and affected by the yawns of others may have evolved because of the result this had in improving survival within groups.”
For the study, they investigated whether seeing others yawn improved the detection of lions, which would likely have been a recurring threat to human survival throughout evolutionary history, compared to impalas, a type of antelope, which would not have represented a danger to our ancestors.
The researchers, whose findings are published in the journal Evolutionary Behavioral Sciences, tested 27 people.
First, they showed them videos of people yawning or with neutral expressions. Then, in random order, they were repeatedly shown images of a lion or an impala in an array of other distractor images and asked them to find the target animal.
“After exposure to people who yawned, participants detected lions more quickly and searched for impalas more slowly,” the researchers said.
A previous study by the same university found that seeing people yawn increased their ability to detect snakes.
By replicating the study with a different animal, the team was able to show that the effect was not just specific to snakes, but in different contexts.
A previous study from the same university found that seeing people yawn increased their ability to detect snakes.
Dr Andrew Gallup, who was involved in both studies, said: “Replications are important to ensure that the original findings are not spurious or due to chance events or statistical anomalies.”
“When we are able to replicate previous experiments, as we have done here, we gain confidence that the findings represent true effects.
“In this case, we also wanted to replicate the previous study to ensure that the effects observed in the original study were not due to the specific type of stimulus used (i.e. snakes).
“By performing a conceptual replication, we show that watching other people yawn improves threat detection, that is, improves vigilance, in different contexts.”