Thursday, December 29, 2011

Inside the mind of the octopus

Did you know that an octopus tastes with its suckers, sees with its skin, and its severed arms can wander about, each with a mind of its own? There are researchers still working diligently to understand what it’s like to be an octopus, how they think, and why they do the strange things they do.

Source: Orion Magazine

A typical human brain has about 100 billion neurons. The common octopus has about 130 million of them in its brain. Three-fifths of an octopus’s neurons are not in the brain; they’re in its arms. “It is as if each arm has a mind of its own,” says Peter Godfrey-Smith, a diver, professor of philosophy at the Graduate Center of the City University of New York, and an admirer of octopuses. For example, researchers who cut off an octopus’s arm (which the octopus can regrow) discovered that not only does the arm crawl away on its own, but if the arm meets a food item, it seizes it—and tries to pass it to where the mouth would be if the arm were still connected to its body. “Meeting an octopus,” writes Godfrey-Smith, “is like meeting an intelligent alien.”

So what does it feel like to be an octopus? Godfrey-Smith has given this a great deal of thought, especially when he meets octopuses and their relatives, giant cuttlefish, on dives in his native Australia. “They come forward and look at you. They reach out to touch you with their arms,” he said. “It’s remarkable how little is known about them . . . but I could see it turning out that we have to change the way we think of the nature of the mind itself to take into account minds with less of a centralized self.”

JENNIFER MATHER SPENT MOST of her time in Bermuda floating facedown on the surface of the water at the edge of the sea. Breathing through a snorkel, she was watching Octopus vulgaris—the common octopus. Although indeed common (they are found in tropical and temperate waters worldwide), at the time of her study in the mid-1980s, “nobody knew what they were doing.”
In a relay with other students from six-thirty in the morning till six-thirty at night, Mather worked to find out.

Sometimes she’d see an octopus hunting. A hunting expedition could take five minutes or three hours. The octopus would capture something, inject it with venom, and carry it home to eat. “Home,” Mather found, is where octopuses spend most of their time. A home, or den, which an octopus may occupy only a few days before switching to a new one, is a place where the shell-less octopus can safely hide: a hole in a rock, a discarded shell, or a cubbyhole in a sunken ship. One species, the Pacific red octopus, particularly likes to den in stubby, brown, glass beer bottles.

One octopus Mather was watching had just returned home and was cleaning the front of the den with its arms. Then, suddenly, it left the den, crawled a meter away, picked up oneparticular rock and placed the rock in front of the den. Two minutes later, the octopus ventured forth to select a second rock. Then it chose a third. Attaching suckers to all the rocks, the octopus carried the load home, slid through the den opening, and carefully arranged the three objects in front. Then it went to sleep. What the octopus was thinking seemed obvious: “Three rocks are enough. Good night!”

The scene has stayed with Mather. The octopus “must have had some concept,” she said, “of what it wanted to make itself feel safe enough to go to sleep.” And the octopus knew how to get what it wanted: by employing foresight, planning—and perhaps even tool use.

Mather is the lead author of Octopus: The Ocean’s Intelligent Invertebrate, which includes observations of octopuses who dismantle Lego sets and open screw-top jars. Coauthor Roland Anderson reports that octopuses even learned to open the childproof caps on Extra Strength Tylenol pill bottles—a feat that eludes many humans with university degrees.

So why is the octopus so intelligent? What is its mind for? Mather thinks she has the answer. She believes the event driving the octopus toward intelligence was the loss of the ancestral shell. Losing the shell freed the octopus for mobility. Now they didn’t need to wait for food to find them; they could hunt like tigers. And while most octopuses love crab best, they hunt and eat dozens of other species—each of which demands a different hunting strategy. Each animal you hunt may demand a different skill set: Will you camouflage yourself for a stalk-and-ambush attack? Shoot through the sea for a fast chase? Or crawl out of the water to capture escaping prey?

Losing the protective shell was a trade-off. Just about anything big enough to eat an octopus will do so. Each species of predator also demands a different evasion strategy—from flashing warning coloration if your attacker is vulnerable to venom, to changing color and shape to camouflage, to fortifying the door to your home with rocks.

Such intelligence is not always evident in the laboratory. “In the lab, you give the animals this situation, and they react,” points out Mather. But in the wild, “the octopus is actively discovering his environment, not waiting for it to hit him. The animal makes the decision to go out and get information, figures out how to get the information, gathers it, uses it, stores it. This has a great deal to do with consciousness.”

“I think consciousness comes in different flavors,” agrees Mather. “Some may have consciousness in a way we may not be able to imagine.”

This is a Suspicious News Brief. Read more at Orion Magazine.

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