Do insects feel emotions?
Charles Darwin once wrote in his book The Expression of Emotions in Man and Animals that insects “express anger, terror, jealousy and love.” That was in 1872. Now, nearly 150 years later, researchers have discovered more evidence that Darwin might have been onto something. Bumblebees seem to have a “positive emotionlike state,” according to a study published in Science. In other words, they may experience something akin to happiness. To some, the idea is still controversial, however.
Unlike humans, you can’t simply ask a bee to interrogate its own emotions and describe them. Instead, researchers have to look for evidence that the insects have the cognitive, behavioral and physiological building blocks that, when combined, can give rise to a complex phenomenon like emotion.
Biologist Clint Perry of Queen Mary, University of London devised an experiment to do just that. He and his colleagues trained bumblebees to distinguish between a blue flower placed on the left side of a container and a green one on the right. When the bees explored the blue flower, they found a 30 percent sugar solution. But when they explored the green one, they slurped up plain, unsweetened water. Eventually, the bees learned to associate the blue flower with a tasty reward.
Then the researchers tested the bees on ambiguously colored flowers at intermediate locations. Half of the insects were given a 60 percent sugar solution prior to the test, and those bees flew faster toward the ambiguous blue-green flower. The remaining bees that were not given the sugar flew more slowly.
The assumption that an ambiguous stimulus contains a reward despite the lack of evidence is called an optimism bias. Perry’s experiment suggests that a bit of sugar amped up the bees into a positive emotional state, making them more optimistic that the flower would contain a sugary treat.
Sound familiar? Something similar is true in humans – newborn infants cry less if they’ve been offered a sweet snack, and a bit of candy increases feelings of positivity and improves bad moods in adults, too. “Many of us view the world in a better way when we have a nice piece of dark chocolate,” Perry says.
There is no intrinsic reason that insects shouldn’t experience emotions. Feelings, on the other hand, are a separate issue. Even though we use the two terms interchangeably in common parlance, scientists use them differently. “Emotions are collections of actions, and numerous species have emoted,” says neuroscientist and philosopher Antonio Damasio of the University of Southern California, “though we can not be certain that they felt their emotings.” In other words, emotions are the body’s adaptive response to external events or stimuli. Feelings are the subjective experience of them.
(Jason G. Goldman. www.scientificamerican.com, 30.09.2016. Adaptado.)
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