14 DAY TRIAL // A collaboration of researchers from the California Institute of Technology and the University of California in Los Angeles discovered in a new study that a very specific region of the brain dictates how humans will react at the sight of an animal, be it a pet or otherwise.
In most people, the sight of a furry animal, especially if very young, will trigger positive emotions such as compassion and empathy. Many would go on to pet the creatures, even if they are lion cubs or other dangerous animals.
However, if the same individuals see a spider, a snake, a crocodile or any other creatures of this nature, they immediately feel fright, revulsion and other negative emotions. This also happens if they see images, movies or hear stories about such animals.
In the new study, the Caltech/UCLA team determined that these responses are all controlled by neurons in the amygdala, a region of the human brain that also plays an important role in regulating our fight-or-flight response, as well as our fears.
The new investigation was conducted on 41 epilepsy patients at the Ronald Reagan UCLA Medical Center, who were asked to watch photos of people, animals, landmarks and various objects. The study is detailed in the latest online issue of the top journal Nature Neuroscience.
In the studies, the team was able to record single-neuron responses from the amygdalae of all test subjects. The two almond-shaped structures making up the amygdala are located in the medial temporal lobe of the human brain.
“Our study shows that neurons in the human amygdala respond preferentially to pictures of animals, meaning that we saw the most amount of activity in cells when the patients looked at cats or snakes versus buildings or people,” researcher Florian Mormann explains.
“This preference extends to cute as well as ugly or dangerous animals and appears to be independent of the emotional contents of the pictures. Remarkably, we find this response behavior only in the right and not in the left amygdala,” the investigator goes on to say.
Mormann is a former postdoctoral scholar from the Caltech Division of Biology and also the lead author of the new paper. “In terms of brain evolution, the amygdala is a very old structure, and throughout our biological history, animals were a highly relevant class of stimuli,” he adds
The new data also suggest that the right hemisphere of all vertebrate animals became specialized in dealing with a number of sudden stimuli that appears in their environments. This is what may have given rise to the flight-or-fight instinct in the first place.