Scientists Sakumi Iki and Ikuma Adachi recently spent a lot of time watching the monkeys scratch themselves.
Self -service among non -human primates is known to indicate social tension and anxiety. The two researchers from the University of Kyoto, Japan, wanted to use this link to find out if the restless (and so woke up) made their monkey subjects more pessimistic or if their pessimism was what led their anxiety.
Their findings Suggest that the first is true, as the primates were more likely to make a pessimistic choice if they had scratched their bodies. This not only provides evidence of an important theory of how normal changes are linked to emotional states, but it also shows that the body language of monkeys can reveal some interesting indications of how animal consciousness can be different from that of humans.
Several studies have previously shown that self-evacuation of primates is linked to social tension and emotional state. For example, a 1991 study found monkeys given anxiety relief It seemed to scratch less, while the monkeys that took a drug caused by anxiety increased self -service.
Have also shown surveys Mosquitoed Captain Monkeys They are more self-sufficient when they are approached by a dominant person, perhaps because of the increased risk of aggression. Japanese macaque With a great tendency to scratch themselves less likely to make peace after a conflict with their team’s comrades.
Researchers of animal and human behavior often use the self -proclaimed measure as a measure of short -term changes in stress, social tension and emotional state. Self -service is also linked to Social tension in people: People often scratch more in a short period of high stress.
Self-scratching is an example of what the behavior scientists call displacement behaviorwhich includes yawning, rim, chopped and face -to -face.
Research has shown that it can also allow us to deal with stress better. For example In 2012, UK researchers asked the participants To make it difficult (and in some cases that cannot pass) numerical calculations in front of an audience and found that participants who showed higher self-post-test rates during the test also reported lower stress level after the test.
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Researchers at the University of Kyoto found that the macaques seem to have a different relationship with the behavior of humans from humans.
Iki and Adachi worked with six adult Japanese macaque (Macaca fuscata). They used videos of a macaque scratching to cause self-revolution in their study issues, since this behavior is contagious, similar to yawning.
They train monkeys to choose between different options on a Greyscale touchscreen. The darker the shade of gray, the more likely the monkeys had to get a food reward.
When they chose the lightest shade of gray, the touchscreen temporarily spread. The darkest shade of gray always rewards the monkeys with food and the three shades in the middle had inconsistent results.
These stimuli examined whether the monkeys were prejudiced to optimism or pessimism. The monkeys who served themselves were more likely to be pessimistic about the outcome of the inconsistent stimuli. The researchers measured pessimism over reaction time.
The more it took a monkey to choose the ambiguous shades, the more pessimistic the researchers believed that the monkeys were. The monkeys did not seem to hesitate if they did not scratch. Researchers argue that scratching was a sign that the monkeys were anxious and anxious made the monkeys more pessimistic about the future.
Their study was one of the first to try what is known as James-Lange’s theory of non-human animals. The theory He argues that there is a successive connection between the behavior and the normal components of our emotions and our experience in these emotions. According to this idea, behavioral and physiological answers occur first. This means, for example, that the possession of an irregular heart pulse would have made us worry.
The new results support James -lange’s theory. Negative emotions (measured by self -service) cause pessimism and not vice versa. The areas of the brain associated with basic emotions, such as fear, are similar to mammals. However, it is not clear whether the way we experience these emotions is comparable to other species.
For example, two human people who have similar normal answers to stress can perceive it differently. One issue can be okay with stress, another issue can fight to handle such a situation. We know that non -human primates have individual responses to stress, but we do not fully know why we cannot ask them.
This study emphasizes interesting similarities and differences between people and other species. A possible difference is related to consciousness. People have a conscious experience of their physical answers that affect the way we respond to them.
An irregular heartbeat can make us anxious. This is not only because it causes a normal anxiety response, but also since we know that something is wrong when we feel that our heartbeat is irregular, which can make us even more anxious.
I say this is “probably” a difference because some researchers argue that other animals, such as chimpanzees or elephants, may have some form of consciousness.
People, unlike the Japanese macas of this study, can also have the opposite template provided for by James-Lange’s theory. If I know I have a test tomorrow, this thought can make my heartbeat become irregular.
The short -term relationship between emotional reactions and the perception of these answers could be shared by many primates (the group of animals that include humans, other monkeys, monkeys and lemur) and other mammals. But research has not yet proved this with definitively.
Research such as Iki and Adachi demonstrate the importance of studying a wide range of species and not just those closest to humans, such as chimpanzees and bonobos, to better understand the factors that shape behavioral and cognitive skills in the animal kingdom.
