To approach the question of love's different forms, the researchers recruited 55 people who all had children and reported living in a loving relationship with another person.
These individuals were asked to listen to pre-recorded texts that described different types of love. The texts dealt with love for a child, a partner, a friend, a stranger, an animal, or nature.
During this time, the researchers noted the participants' brain activity using a magnetic resonance camera, MRI.
Love is so fundamental to humans, and there are so many variants, but it's almost only romantic love and love between parents and children that have been studied neuroscientifically, says Pärttyli Rinne at Aalto University and one of the researchers behind the study.
Friend vs. animal
The results, published in the Cerebral Cortex journal, showed that different types of love feelings activated different parts of the brain. When parents imagined love for their child, activity was seen deep in the brain's reward system, which was unique to parental love.
Thoughts of love for a stranger or a more superficial acquaintance gave rise to different reactions than those for a partner. However, all of these increased activity in parts linked to social interaction. Love for nature, on the other hand, increased activity in parts related to visual impressions.
Revealing pet owners
An interesting difference was seen regarding feelings for animals. If the participants listened to a scenario involving a cat or a dog, parts of the brain related to social interaction were activated in those who had a pet. However, this activity was not seen in others. Brain activity could thus reveal whether people were pet owners.
This was what surprised me the most, it was so clear, says Pärttyli Rinne.
If different types of love feelings are visible in the brain - could one in the future use an MRI camera to determine if someone is in love with you or just likes you as a friend?
Pärttyli Rinne's answer is cautious.
Although the results were clear at the group level, there are likely individual differences, he says.
55 individuals were asked to listen to pre-recorded texts with the instruction to immerse themselves in the type of love described. At the same time, activity in different parts of the brain was noted using MRI.
Examples of what was played included: "Your child runs towards you on a sunny meadow. You both smile, and the sun glitters in the child's face. You feel love for your child."
"You need help moving, so you call a friend. The friend says yes, and soon you're lifting boxes together. As you do this, you feel a strong love for your friend."
The images showed that different types of love feelings increased activity in different parts of the brain. The largest differences were seen when participants listened to texts about other people, nature, or animals.
An exception was pet owners, who had higher activity in the "social" parts of the brain than non-pet owners when thinking about animals.
Source: Cerebral Cortex journal