What makes yawning contagious?
Does this picture make you feel a bit sleepy? Image credit: Natasha Lelenco via Flickr
Yawning. It’s so common that no one really turns a blind eye when it happens. However, I’m sure many people have questioned why when one person yawns, it seems inevitable that others in the room will too. Yawning’s contagious nature is well-known, although I’m not sure many know the causes.
Whilst I’d love to explain why we yawn in general, there are many conflicting theories on the issue. So instead off diving into the complex arguments for why we yawn, I will instead explore the causes of its contagiousness.
Evidence suggests that the infectious effect of yawning is due to a human’s ability to feel empathy; the ability to understand another person’s emotions. It could then be suggested that individuals must be emotionally attached to other people to feel the contagious effects of yawning. If we rely on this logic, individuals who struggle with social interactions, such as those who suffer autism and other mental illnesses that effect one’s capacity to read other people’s emotions, are less susceptible to the contagious nature of yawning.
So we know that a person must have the ability to feel empathy to be susceptible, but how does the transmission of yawning from one to another actually occur? It involves a complex neural pathway referred to as the mirror neuron complex. The complex is activated when a person observes another yawning; triggering them to imitate the behaviour of that individual. This mirror neuron activity is not exclusive to just yawning, but is involved in numerous behaviours that involve imitation. Neuron activation is greatest when a person observes the controlled facial movements involved in acts such as yawning.
Whilst the contagious effects are observable in adults, I suggest next time you take a big yawn, look around at any younger children around you. What you should notice is that children under the age of five (approximately) are invulnerable to catching a yawn. This indicates that the mirror neuron complex and sense of empathy develop in early childhood. Therefore, up until the age of around five years old a child will dodge the contagious effects of yawning.
Yawning effects young and old, but only those who’ve developed empathy will feel its contagious effects! Image credit: Daniele Paccaloni via Flickr
In studies of human communities, it was recognised that a chain of yawns was more often initiated by a senior member of the group or authoritative member, in comparison to individuals who express less power in the community. This is thought to be due to messages from individuals holding more power in the group being more actively adhered to by other, less powerful members of the group.
Whilst these observations do not suggest what causes spontaneous yawns, such as when people are alone with no contact with others, scientists have suggested that being in the presence of others may supress yawning to start with. Whilst I haven’t seen anything suggesting this, I ask the question, is it because in the presence of others, we are less bored? We are preoccupied by their company and are less likely to feel drowsy? Perhaps these are some questions for further investigation into the mysterious act of yawning.