When someone
yawns it’s hard not to follow suit.
The contagious nature of yawning has prompted scientists to study the
effects and reasons why people yawn.
One theory is that humans yawn because of an empathic response that is
developed in early childhood.
Another theory is that empathy was developed from an evolutionary
standpoint to increase fitness of organisms. More recently, scientists have leaned more towards a
combination of the two theories as a means of explaining how empathy is
acquired.
Jean
Decety discusses in an article the nature of human development and how empathy
is gradually learned. “In a study of
development of concern for others, Zahn-Waxler
et al. (1992) found that rates of expressions of
empathy and sympathy toward a distressed adult increased significantly between
13 and 24 months of age, and that reactions of personal distress were gradually
replaced by more constructive, action-oriented patterns.” (Decety, Svetlova,
2012, p. 13) Here Decety cites how children as early as 13 months start to
develop the ability to understand the emotions of others. He discusses how between 13 and 24
months there is a significant increase in how the child reacts to the emotions
of others. Early in development,
children show personal distress in response to other people’s pain. Over the
course of development, however, the children shift to more useful reactions to
the stimulus. This not only shows
a developmental basis for acquiring empathetic abilities but could lead to an
evolutionary basis as well.
Children who don’t recognize that they are in danger due to the way
their mother is acting may end up crying or making noise when a predator is
hunting and be the difference between surviving and being a meal. One form of empathy that has interested
scientists, in terms of development and evolution, is yawning.
Many
studies have been done on humans regarding yawning, but recently a different
study has been done with dogs. The
group of dogs ranged from four to 14 months old. A human was introduced and yawned. When he did the dogs over the age of 7 months yawned and
none of the dogs under 7 months yawned. (Springer Science + Media) This age difference in yawning in dogs
is consistent with the age difference in humans with regards to developmental
period. These age groups are consistent with a period in development that is
associated with rapid growth in mental functioning. This leads scientists to believe that, in mammals, there is
a critical period where empathy is learned.
The
study also found that there might be a correlation with the introduction of the
yawn and tiredness in the dogs.
The dogs that yawned also showed a decrease in arousal. Moreover, the experimenter was required
to take action to prevent the dogs from falling asleep. Viewing this from an evolutionary
standpoint, this decrease in arousal could stem from the dogs in the pack
traveling and when the alpha male was tired he communicated this to the rest of
the dogs through yawning. The same
decrease in arousal has also been seen in some human experiments and the same
theory can be applied to humans as well.
Scientists
are still trying to determine how and why humans, and other animals, developed
empathy. The main theory is that
it was selected for in evolution and it has a specific period of development
early in childhood. With further
research scientists will be able to figure out the questions they still have
and continue their understanding of empathy.
Decety, J.,
Svetlova, M. (January 24, 2012). Putting
together phylogenetic and ontogenetic perspectives on empathy.
Springer Science+Business Media (2012,
October 23). Puppies don't pick up on yawns: Dogs, like humans, show a gradual
development of susceptibility to contagious yawning. ScienceDaily. Retrieved
December 11, 2012, from http://www.sciencedaily.com /releases/2012/10/121023100942.htm
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