Any person is likely to pinch an infant's cheeks in response to his/her cuteness. This phenomenon is the subject of a new research that explores how the brain reacts on cute stimuli.

Katherine Stavropoulos, a licensed clinical psychologist and assistant professor at the University of California, Riverside, used electrophysiology to determine the amount of electrical impulses fired by neurons when a person sees cute images.

Targeting The Brain's Reward System

Stavropoulos and UCR doctoral student Laura Alba recruited 54 adults aged 18 to 40 years to join their experiment. The participants consented to wearing an electrode cap that will measure their neural activities as they presented photos of babies and animals. They were then shown a set of statements for which they expressed their agreement on a scale of one to 10.

"There was an especially strong correlation between ratings of cute aggression experienced toward cute animals and the reward response in the brain toward cute animals," Stavropoulos said.

She added that cute aggression takes place when a person is overwhelmed by how cute something is. Stavropoulos confirmed the theory that the intensity of cute aggression is directly related to the person's level of being overwhelmed.

More importantly, Stavropoulos said that cute aggression enables human beings to take care of something or someone that they perceive as cute. She hopes that her study on cute aggression will encourage future researchers to explore its effects on different populations such as mothers with postpartum depression and individuals with autism spectrum disorder.

Stavropoulos' work is published Dec. 4 in Frontiers in Behavioral Neuroscience.

Why Tears Of Joy Make Sense

Stavropoulos' research is inspired by a related study conducted by a team of Yale psychologists that looked at the expression of negative emotions in response to positive experiences. The team, which was led by Yale psychologist Oriana Aragon, investigated why humans cry when they are happy and other examples of cute aggressions.

"People may be restoring emotional equilibrium with these expressions," Aragon said. "They seem to take place when people are overwhelmed with strong positive emotions, and people who do this seem to recover better from those strong emotions."

Examples of negative emotions tied to positive experiences are audiences screaming in tears after their favorite soccer team scored a winning goal, soldiers returning home, or parents welcoming their new child.

Aragon's study is published 2015 in the Psychological Science.