Other Minds: The Octopus and the Evolution of Intelligent Life. Peter Godfrey-Smith

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СКАЧАТЬ materially with the smooth conduct of the experiments, and is, again, clearly incompatible with lever-pulling.

      Dews comments dryly, “The variables responsible for the maintenance and strengthening of the lamp-pulling and squirting behavior in this animal were not apparent.” The language Dews is using here – the language of “variables responsible,” and so on – shows that he is thinking (or writing, at least) in line with the assumptions of mid-twentieth-century animal behavior experiments. He assumes that if Charles is squirting experimenters and absconding with the apparatus, this must be because something in Charles’s history has reinforced this behavior. Animals of a given species will start out the same, on this view, and if they diverge in behavior this must be because of rewarding (or unrewarding) experiences. That is the framework Dews is working within. However, one message of octopus experiments is that there is a great deal of individual variability. Charles, most likely, was not an octopus who started with the same behavioral routines as the others and was reinforced for squirting experimenters, but an octopus with a particularly feisty temperament.

      This 1959 paper was one of the first encounters between a tightly controlled style of scientific work on animal behavior and the idiosyncrasies of the octopus. A great deal of work on animals has been done under the assumption that all animals of a given species (and perhaps of a given sex) will be very similar until they encounter different rewards, and will peck or run or pull a lever all day in order to get the same little morsels of food. Dews, like many others, wanted to work this way because he was determined to use what he called “objective, quantitative methods of study.” I am all for those, too. But octopuses, far more than rats and pigeons, have their own ideas: “mischief and craft,” as Aelianus, in this chapter’s epigraph, had it.

      The most famous octopus anecdotes are tales of escape and thievery, in which octopuses in aquariums raid neighboring tanks at night for food. Those stories, despite their charm, are not especially indicative of high intelligence. Neighboring tanks are not so different from tide pools, even though the entrance and exit take more effort. Here is a behavior I find more intriguing. Octopuses in at least two aquariums have learned to turn off the lights by squirting jets of water at the bulbs when no one is watching, and short-circuiting the power supply. At the University of Otago in New Zealand, this became so expensive that the octopus had to be released back to the wild. A lab in Germany had the same problem. This seems very smart indeed. However, one can also sketch an explanation which may partially deflate the story. Octopuses don’t like bright lights, and they squirt jets of water at all sorts of things that annoy them (as Peter Dews discovered). So squirting water at lights might not be something that requires much explanation. Also, octopuses are more likely to roam far enough away from their dens to squirt at this particular target when no humans are around. On the other hand, both the stories of this kind that I’ve seen give the impression that the octopus learned very quickly how well this behavior works – that it’s worth getting into position and aiming right at the light, to turn it out. It should be possible to set up an experiment that tests some of the various possible explanations for the behavior.

      This case illustrates a more general fact: octopuses have an ability to adapt to the special circumstances of captivity and their interaction with human keepers. Octopuses in the wild are fairly solitary animals. Their social life, in most species, is thought to be minimal (though later I’ll look at exceptions to this pattern). In the lab, however, they are often quick to get the hang of how life works in their new circumstances. For example, it has long appeared that captive octopuses can recognize and behave differently toward individual human keepers. Stories of this kind have been coming out of different labs for years. Initially it all seemed anecdotal. In the same lab in New Zealand that had the “lights-out” problem, an octopus took a dislike to one member of the lab staff, for no obvious reason, and whenever that person passed by on the walkway behind the tank she received a jet of half a gallon of water in the back of her neck. Shelley Adamo, of Dalhousie University, had one cuttlefish who reliably squirted streams of water at all new visitors to the lab, and not at people who were often around. In 2010, an experiment confirmed that giant Pacific octopuses can indeed recognize individual humans, and can do this even when the humans are wearing identical uniforms.

      Stefan Linquist, a philosopher who once studied octopus behavior in the lab, puts it like this: “When you work with fish, they have no idea they are in a tank, somewhere unnatural. With octopuses it is totally different. They know that they are inside this special place, and you are outside it. All their behaviors are affected by their awareness of captivity.” Linquist’s octopuses would mess around with their tank, manipulating and testing it. Linquist had a problem with octopuses deliberately plugging the outflow valves on the tanks by poking in their arms, perhaps to increase the water level. Of course, this flooded the entire lab.

      Another tale that illustrates Linquist’s point was told to me by Jean Boal, of Millersville University in Pennsylvania. Boal has a reputation as one of the most rigorous and critical of cephalopod researchers. She is known for her meticulous experimental designs, and her insistence that “cognition” or “thought” in these animals should be hypothesized only when experimental results cannot be explained in any simpler way. But like many researchers, she has a few tales of behaviors that are baffling in what they seem to show about the inner lives of these animals. One of these incidents has stayed in her mind for over a decade. Octopuses love to eat crabs, but in the lab they are often fed on thawed-out frozen shrimp or squid. It takes octopuses a while to get used to these second-rate foods, but eventually they do. One day Boal was walking down a row of tanks, feeding each octopus a piece of thawed squid as she passed. On reaching the end of the row, she walked back the way she’d come. The octopus in the first tank, though, seemed to be waiting for her. It had not eaten its squid, but instead was holding it conspicuously. As Boal stood there, the octopus made its way slowly across the tank toward the outflow pipe, watching her all the way. When it reached the outflow pipe, still watching her, it dumped the scrap of squid down the drain.

      This story, along with all the tales of octopuses squirting experimenters, reminded me of something I’d seen myself. Captive octopuses often try to escape, and when they do, they seem unerringly able to pick the one moment you aren’t watching them. If you have an octopus in a bucket of water, for example, it will often look content enough in there, but if your attention strays for a second, when you look back there will be an octopus quietly crawling across the floor.

      I thought I might be imagining this tendency, until I heard a talk a few years ago given by David Scheel, who works with octopuses full-time. He, too, said that octopuses seem to track in subtle ways whether he is watching them or not, and they make their move when he isn’t. I suppose this makes sense as a natural behavior in octopuses; you want to make a run for it when the barracuda is not looking at you, rather than when he is. But the fact that octopuses can so quickly do this with humans – both with scuba mask and without – is impressive.

      As stories of this kind accumulate, an explanation suggests itself for the mixed results with octopuses in some standard learning experiments. It’s often said that they don’t do especially well in these experiments because the behaviors required are unnatural. (Hanlon and Messenger said this about the Dews experiment with the lever pulling, for example.) But octopus behavior in laboratory settings indicates that “unnatural” is often no problem for them. Octopuses can open screw-cap jars for food, and one has even been filmed opening such a jar from the inside. Behaviors don’t get much more unnatural than that. I think the problems with the old Peter Dews experiment, such as they were, came in part from the assumption that an octopus would be interested in pulling a lever repeatedly to get pieces of sardine, collecting piece after piece of this second-rate food. Rats and pigeons will do things like that, but octopuses take a while to deal with each item of food, probably can’t cram themselves, and tend to lose interest. For at least some of them, taking the lamp down from above the tank and hauling it back to the den – that is more interesting. So is squirting the experimenters.

      In response to the difficulty of motivating the animals, some researchers, regrettably, have used СКАЧАТЬ