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.
Octopuses are intelligent creatures and are even capable of solving puzzles.
Researchers studied the genome of a kind of octopus not known for its friendliness toward its peers, then tested its behavioural reaction to a popular mood-altering drug also known as ecstasy.
Octopuses on MDMA act like people on the same drug, revealing a new evolutionary connection between the two species.
Octopuses' social response is curious because humans and octopuses have more than 500 million years of divergent evolution, making us very different creatures indeed.
"Just because they have the protein", she says, "doesn't mean that when MDMA binds to the protein it's going to do anything like what it does in a human or a mouse".
Under normal conditions, without MDMA, five male and female octopuses avoided only male, caged octopuses. Whether that demonstrates an increase in something like love or affection for each other, though, is still up for debate.
The experiment conducted, Fortune reported, involved placing a "hand-sized" octopus in the center chamber of a three-chambered tank.
The study was led by Gül Dölen, assistant professor of neuroscience at the Johns Hopkins University School of Medicine who explained that the brains of these octopuses are more similar to snails than to humans but the behavioural reactions noted are similar to humans. But, serious interest in MDMA has grown as researchers have begun discovering promising applications of the drug in treating PTSD and other disorders. Dölen wondered if the drug would have similar effects on animals that it does on humans.
Then they were placed in the experimental chambers for 30 minutes.
One octopus was doing back flips, according to Dr Dolen, who said that some of the behaviours were so odd the research team couldn't quantify them. "They just embraced with multiple arms".
"It's not just quantitatively more time, but qualitative", Dölen said in a statement. The other octopus was allowed to roam freely. Also in that tank was another octopus that was confined to a cage - well, really an upside-down flower pot with holes in it. Octopuses would ordinarily stay far away from the imprisoned stranger, but not so on ecstasy.
Enter other species. There is a long, and sometimes dubious, history of scientists dosing animals with psychoactive drugs. They absorbed the MDMA through their gills. She says octopuses have a very different, doughnut-shaped brain. However, on a lower dose, one octopus appeared to be "doing water ballet", swimming around the tank with tentacles outstretched.