“This paper is welcomed, as the behavioral neuroscience of cephalopods is very understudied,” Dalhousie University invertebrate behavioral physiologist Shelley Adamo, Ph.D., who was not involved with the current paper, tells Inverse. Adamo also studies the interactions between behavior and physiology in invertebrate model systems. “We know little about how their brains work. This paper breaks new ground by examining the underlying molecular basis of at least one neurotransmitter system.”
But she also cautions that it’s too early to jump to conclusions because the paper’s evidence that “the octopus were engaging in ‘social’ behaviors is not especially strong.” There could be alternative explanations for all that friendliness. Maybe the drug altered their foraging behavior and the target octopus “smelled” like food (cephalopods are occasionally cannibalistic). Maybe the MDMA changed their typical hunting behavior, and being hungry could explain why both male and female octopuses were interested in the target.
“As with most interesting papers, it raises a number of questions: What would two octopus do if they were both on MDMA and they could contact one another?” Adamo asks. “The small sample size — a necessary evil for most studies on cephalopods — means that the data is not as robust as it could be.”
Dölen has two hypotheses to explain what happened. Qualitatively, it looks like octopuses on MDMA, much like humans, could just like touching in general,, and the octopus in the cage “is the most interesting object that an octopus would want to touch.” Or it could be that the drug really does make them social. The latter, she believes, is the most robust hypothesis: MDMA affects human interest in social touch as well, and that seems to be preserved in octopuses as well.