Calling octopuses intelligent beings might seem like a stretch. After all, the eight-armed invertebrates count the everyday garden snail among their close evolutionary cousins. But octopuses are experts in camouflage, can deter predators with poisonous bites, engage in play, solve complex problems, and can squeeze themselves into tiny crevices when threatened. Such observations indicate that the octopus is without a doubt smarter than the average snail, but the nature of this intelligence remains unknown. Considering that our branches on the evolutionary tree are separated by more than half a billion years, can the intellect of an octopus bear any comparison to that of a human? City University of New York philosopher Peter Godfrey-Smith has begun a unique collaboration with a team of Australian marine scientists to examine this distinctly philosophical question using biological research.
Godfrey-Smith spends nearly every summer in his native Sydney. His love of diving in the city’s harbor bore scientific fruit when he captured a rare photograph of gloomy octopuses (Octopus tetricus) mating and published his observations of the event in a short paper with marine biologist Christine Huffard of Conservation International Indonesia (Moll Res, 30:81-86, 2010). Godfrey-Smith started teaching himself about octopus biology, focusing on their nervous systems and brains.
Most invertebrates have ladderlike nervous systems with knots of neurons connected by nerve fibers. Vertebrate nervous systems are instead dominated by one big clump of neurons—the brain. Octopuses, along with their cephalopod cousins squid and cuttlefish, seem to be an evolutionary in-between. Their nervous system retains some knot architecture—more than half of their 500 million neurons are distributed throughout their eight arms—but they also have a large central brain.
“It is fascinating to think about cephalopod cognition, since they are mollusks,” says Jean Boal, a biologist at Millersville University in Pennsylvania.“Their ancestors are clams and snails and slugs, which are not very bright. The environment has pushed them toward evolving cognition that looks and functions a lot like vertebrate cognition.”
Part of the point of philosophy is to try and address life’s mysteries. Biologists do the same thing. I think there should be a stronger connection between the two fields.—Peter Godfrey-Smith
Godfrey-Smith decided to connect this biological concept with his interest in the philosophy of mind, particularly in nonhumans. In 2010, he began a project with Alexandra Schnell, a graduate student at Macquarie University in Sydney, to conduct behavioral observation studies that address whether octopus intelligence differs from that of other species. Do octopuses learn differently? Does the decentralization of neurons mean cephalopods have multiple minds or competing consciousnesses?
“When you watch an octopus, it does look like the arms engage in independent exploration, they feel around individually,” says Godfrey-Smith.
In early experiments, conducted in the summer of 2010 at the Sydney Institute of Marine Science, Godfrey-Smith and Schnell noticed peculiar behavior in an octopus in an unfamiliar tank with food in the middle. “When the arms reached the food, it seemed as though they were hauling the octopus toward the center while [other of its arms] were pulling to keep it in the corner,” as if there was a “tug of war” occurring within the animal, the philosopher recalls. The researchers later realized that too much light shining in the tank might have influenced the reaction.
That same summer, they popped gloomy octopuses into aquaria with a high-definition TV positioned alongside one wall. They screened a video of a human hand unscrewing the cap on a jar with a crab claw inside to see if the octopuses could mimic the movement. The experiment was designed to uncover clues as to how they may learn.
According to Godfrey-Smith, initial observations yielded potentially promising results, with the octopuses showing hints of learning by mimicry. Unfortunately, before conclusions could be drawn and follow-up studies arranged, the octopus learning trials were cut short when the Sydney Institute of Marine Science started renovating all of its aquarium facilities earlier this year. Godfrey-Smith and Schnell are currently searching for a new research facility, and they hope to reboot the learning trials this month.
“I think it is a big advantage having an interdisciplinary team, because there are different ways of thinking when coming from a dominant scientific or philosophical educational background,” says Schnell. “The project has benefited from our unique union, and I have learned to take a more eclectic view of science due to his philosophical perspective on addressing questions.”
Godfrey-Smith is hoping to see more collaboration between philosophers and researchers to address scientific questions. “Part of the point of philosophy is to try and address life’s mysteries. Biologists do the same thing. I think there should be a stronger connection between the two fields,” he says.