Tests on 17 women found that they were less affected by stinging sensations while looking at pictures of their partners.
But their levels of discomfort actually increased when they were staring at images of spiders, objects or strangers.
The findings could help to pinpoint how emotions act on different areas of the brain and how uncomfortable feelings can be dealt with.
‘On a practical level if you are someone enduring pain or going in for a painful procedure bringing a loved one with you or brining a picture of a loved one with you may reduce the pain of the experience,’ the study’s lead author Naomi Eisenberger told the Toronto Star.
Ms Eisenberger, an assistant professor of psychology at the University of California, Los Angeles, carried out the tests on 17 different women who were in long-term relationships.
An earlier study discovered that women felt less pain while they were either looking at a picture of their partner or while the person was holding their hand.
But this study, published in Proceedings of the National Academy of Science, is the first time that scientists have been unable to find the area of the brain that is responsible for the feelings.
Researchers used MRIs to monitor the women’s brains while administering stinging shocks to their body.
The women stared at pictures varying from their partner, strangers, or solid objects. They were then given a 20-point scale to use to rate their pain after each shock.
The pain scores were significantly lower for the women when they were looking at a picture of their partner.
The researchers discovered activity in the ventromedial prefrontal cortex which is associated with a feeling of safety.
Brain: The ventromedial prefrontal cortex was linked to feelings of safety
The longer the women had been in the relationship and the more supported they were by their partner, the greater the level of activity in the ventromedial prefrontal cortex, or VMPFC
The VMPFC is capable of inhibiting other pathways in the brain responsible for fear and anxiety. This area was also able to reduce pain, the researchers found.
Researchers also discovered that the dorsal anterior cingulate cortex, an area responsible for stress response, was less active when the women were looking at the photos of their other halves.
‘We also found that people in longer relationships were showing greater activity in that region,’ Eisenberger added.
She said that it could be arguesd that people who have been in their relationship longer may view their partner as a stronger cue for safety.
She added: ‘This shows how strong of an effect our loved ones can have on us. They can lead us to feel less pain even when we’re simply reminded of them or looking at a picture of them.’
Ms Eisenberger said that the images of snakes and spiders could have produced the opposite effect because ‘over the course of our evolutionary history things like snakes and spiders have threatened our survival’.