Psychoactive drug MDMA, often referred to as ecstasy or molly, can make people feel extra affectionate due to a rush of serotonin, dopamine and oxytocin. These "pro-social" behaviors were incredibly obvious in the experiments, and the research could help open new doors to understanding how animals socialize and what inhibits or promotes touchy-feeling behavior in the animal kingdom.
Octopuses are nearly entirely antisocial, except when they're mating, and scientists who study them have to house them separately so they don't kill or eat each other. Put two in the same tank, and they will usually stay far away from one another - or try to kill and eat each other. So how would octopuses, who display similar emotional traits as a human, react under the influence of MDMA?
And yes, the octopuses acted like they took ecstasy. What sounds like the premise of a children's book set at Burning Man is, in fact, the conclusion of a study published Thursday in the journal Current Biology.
American biologists have found that species of the California two spotted octopus react to ecstasy is exactly the same as the people become more social.
A neuropsychopharmacologist at Imperial College London named Professor David Nutt said the results of this study also provide more evidence that a wide range of species experience emotion and empathy: "This just proves that this is not some peculiar human characteristic, it's not even a mammalian characteristic, it's a characteristic of brains".
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. They spend more time around the octopus in the cage, even spreading their limbs to symbolize "an eight-armed hug". While several invertebrates (e.g., bees, ants, and shrimps) and vertebrates (e.g., fishes, birds, rodents) in the animal kingdom display social characterizes, the octopus only suspends its reclusiveness during mating season - indicating a suppression of social behavior outside the reproductive period.
"I have to admit that it was totally trial and error". And those octopuses spent significantly more time, on average 15 minutes, in the room with another male octopus.
Researchers Eric Edsinger, Ph.D., and Gül Dölen, M.D., Ph.D. had a closer look at the genomic sequence of the California two-spot octopus and found that they and humans have almost identical genomic codes for the transporter that binds serotonin, a mood regulator, to the neuron's membrane.
Dolen said she would like to do more tests with more animals, such as giving MDMA to an octopus at the same time as Prozac or a selective serotonin reuptake inhibitor that bind to the same receptor.
Then, they were exposed to a liquefied version of MDMA, which they absorbed through their gills, and placed in the chambers again.
As for the octopuses - who were hatched in the lab, not caught in the wild - they went through this entire trip just fine. Scientists chose to use octopuses for the experiment as humans are separated by more than 500 million years of evolution with them and the goal was to uncovering the ancient origins of social behavior.
"An octopus doesn't have a cortex, and doesn't have a reward circuit", Dölen said.