Increased testosterone levels are linked to decreased empathy

Neurology: The dark side of the cuddle hormone oxytocin

It makes you friendly, monogamous and fearless - but also jealous, careless and trusting: the list of effects attributed to the hormone oxytocin is long. "Some studies are methodologically questionable," emphasizes the Freiburg psychologist Markus Heinrichs, a pioneer in human oxytocin research. The results therefore lack a scientific basis. "The interpretations are sometimes almost esoteric."

For decades it was only known as a labor or breastfeeding hormone in obstetrics. Then experiments with rodents showed that it also influences social interaction outside of mother-child relationships and can reduce stress and anxiety. When mating, for example, oxytocin is activated in the brain, promotes couple bonding and partner recognition, at the same time reduces general fear behavior, calms stress systems and increases general well-being.

The fact that the messenger substance, administered with a nasal spray, could also change social behavior in humans was initially considered completely absurd, says Heinrichs. "At the end of the 1990s, many highly respected experts laughed out loud at this idea."

More trust in others

"Like a bomb" then hit a study presented in the journal "Nature" in 2005, says René Hurlemann from Bonn University Hospital. The researchers led by Heinrichs, who was teaching at the University of Zurich at the time, sprayed test subjects with oxytocin or an ineffective placebo into the nose. Then the students were given the role of lender. The result: With oxytocin they decided more generously, their trust in others was apparently increased.

This showed for the first time that even a complex being like humans can be influenced with a simple hormone nasal spray. At first there was great skepticism in the professional world, but then there was almost limitless enthusiasm. In the meantime, research has reached inflationary proportions, says Heinrichs. “It is obviously a real fashion. Everyone would like to do an oxytocin study. "

The list of interesting results is correspondingly long: If people are administered oxytocin with a nasal spray, their cognitive empathy increases, says Hurlemann. It is easier for them to read from the area around their eyes how they are doing. Another analysis showed that amygdala activity was reduced in participants who received oxytocin through the nose. As a result, they reacted less to fearful images.

Social empathy is strengthened