Our meeting was occasioned by the recent paper in PNAS about the mental map of bees ("Way-finding in displaced clock-shifted bees proves bees use a cognitive map", Cheeseman et al.). Cognitive maps are mental representations of physical places, which mammals use to navigate their surroundings. Insects clearly have ways to do the same; whether or not they do it with cognitive maps is the question.
The "computational theory of mind" is the predominant theory of how mammals think -- the brain is posited to be an information processing system, and thinking is the brain computing, or processing information (though, whether this is 'truth' or primarily a reflection of the computer age isn't clear, at least to us). In vertebrates some at least of this takes place in the section called the hippocampus, or in non-vertebrates in some neurological homologs. But, what do insects do?
Previous work has shown that captured insects, once released, often fly off in the compass direction in which they were headed when they were caught, even if they were moved during capture and the direction is no longer appropriate. But, they then can correct themselves, and then have no problem locating their hives. That indicates that they've got some kind of an "integrated metric map" of their environment.
Some theories have held that they mark the location of the sun relative to the direction they take and then later calculate 'home' based on a computation of time and the motion of the sun. This by itself would be a lot of sophisticated computing, or thinking....and why not 'intelligence'?
Cheeseman et al. asked whether instead what they are relying on is a series of snapshots of their environment, which enables them to recognize different landmarks, one after the other as they come into view, rather than a completely integrated mental map. They experimented with anesthetizing bees and shifting their sense of time, so that they couldn't rely on the sun to get them home. It took some flying for the bees to recognize that they were off-course, but they always were able to re-orient themselves and get back to the hive.
Cheeseman et al. conclude that that because bees don't rely entirely on a sun-compass for their sense of direction, they must have the apian equivalent of a cognitive map. That is, they collect relevant spatial information from the environment with which they navigate, and use it to make decisions about how to get where they are going. That is, they take and file away snapshots; remember that insect eyes are complex, including two compound eyes and in most species three forehead-located small, simpler ocelli so this is synthesizing a many-camera pixellation and differently sensitive integration of the light-world. Then, they use a sequence of these frames, later, from a different position from that at which the photos were taken so not all landmarks might even be visible, and at a different time, which can affect shadows, colors, and so on. Then, tiling these lined up in reverse order in mirror left-right flipped order somehow, and adjusting their angles of perspective and so on, also perhaps sound, wind direction, and even perhaps monitoring the olfactory trail (also in reverse relative position) like Hansel and Gretel's bread crumbs, they head home for dinner.
|Two big compound eyes, and 3 simpler central ocelli. From http://188.8.131.52/news/valleycarpenterbees.html|
To us, this is a remarkable feat for their small brains! For some of us, even with a human brain, finding one's way home without a GPS is no easy task, and deserves a nice cold drink when done successfully. However, the philosophers we were chatting about this with did not think what Cheeseman et al. believe they discovered about bees should be called a cognitive map because, and we think we've got this right, they haven't got a mental image of the entire lay of the land. Instead it's as though they are connecting the dots; they recognize landmarks and go from one mental snapshot with a familiar landmark to the next. So what kind of 'intelligence' this is becomes a definitional question perhaps. Call it mechanical or whatever you want, we would call this 'intelligent' behavior.
We don't know enough about philosophy (or the biology) of the mind to know how significantly these two models differ, or whether 'consciousness' is subtly underlying how these judgments about cognition are made, but in any case, that's not what interested us about the bee story. What is the experience of being a bee? Whichever kind of imaging and processing they do to navigate, how do they turn the locational information into action? It's one thing to know that your hive is east (or the apian equivalent) of the pine tree, but getting there requires "knowing" that after you've collected the nectar, you then want to bring it home, and that means you have to find your way there. Your mental map, whatever it consists of, must be made operational. How does that happen, in a brain the size of a bee's? Or an ant's?
Or bird brains? Crows, corvids, are considered among the smartest of birds. Their problem solving skills have been documented by a number of researchers, but crows have fascinated many non-scientists as well, including our son, who sent this observation from Lake Thun in Switzerland.
Crow found a little paper cup with some dried out dregs of leftover ketchup in the bottom. This is the sort of little paper condiment cup that would come with some french fries. We watched the crow try a couple of times to scrape some ketchup out with his beak, holding the cup down with his foot. It apparently wasn't working enough to his satisfaction, so he flew with the cup to the edge of the water (we were at the lake). He wanted to get the ketchup wet to "hydrate" it, to make it easier to scoop out. That was impressive enough, but what he did next was even more. There were little waves lapping on the "shore" (this was actually in a harbour and the shore was concrete) and each time threatening to carry away his cup. So he picked up the cup and carried it along up and down the shore until he found a little crevasse in the concrete that he could secure the cup, and let the water wash over it without taking it away. Clever.If that's not intelligence, it's hard to know what it is, then.
One view of intelligence is that it's what's measured by IQ tests. Or, at least, what humans think 'thinking' is all about. But this is perhaps a very parochial view. We tend to dismiss the kind of intricate brainwork that is required by nonverbal activities, or by athletes, or artists, or artisans. We tend to equate intelligence with verbal kinds of skills measured on tests devised by the literate segments of society who are using the results to screen for various kinds of western-culture activities, suitability for school, and the like. There's no reason to suggest that those aspects of brainware are not relevant to society, but it is our culturally chosen sort of definition.
Philosophers and perhaps most psychologists might not want to credit the crow with 'intelligence', or they may use the word but exclude concepts of perceptual consciousness--though whether there are adequate grounds for that that are not entirely based on our own experience as the defining one, isn't clear (to us, at least). In any case, wiring and behavior are empirically observable, but experience much less so, and consciousness as a component of brain activity, and perhaps of intelligence, remains elusive because it's a subjective experience while science is a method for exploring the empirical, and in that sense objective world.
If bees and, indeed, very tiny insects can navigate around searching the environment, having ideas about 'home', finding mates, recognizing food and dangers, and they can do it with thousands rather than billions of neurons, at present we haven't enough understanding of what 'thinking' is, much less 'intelligence', to know what goes through a bee's or a crow's mind when they're exploring their world....