“After MDMA, they were essentially hugging,” says Dolen, who explains that the octopuses were “really just much more relaxed in posture, and using a lot more of their body to interact with the other octopus.”
To her, the results published in the journal Current Biology show that “serotonin has been encoding social functions for a very, very long time. At least 500 million years ago, it started doing this function.”
Zachary Mainen, a neuroscientist at the Champalimaud Centre for the Unknown in Portugal, points out that some research done decades ago showed that giving extra serotonin to lobsters can alter their social behavior.
“Specifically,” Mainen explains, “if you give them more serotonin, they become more dominant. A small lobster given serotonin will become a more aggressive, socially dominant lobster.”
He says MDMA, which affects the serotonin system, clearly effects the octopuses’ social behavior, but it’s not clear to him if it’s really inducing greater love for another creature.