Evolutionary Psychology Blog Archive

Defining Deception

At the event that I mentioned in a prior blog post, the workshop entitled, “Lying: The Making of the World” at Arizona State University, the assembled biologists, psychologists, philosophers and others discussed, perhaps less than one might have thought, how to define whatever it was they all assembled to discuss. How should terms the terms “lying” and “deception” be defined?

Defining “lying” seems, to me, harder than defining “deception” because lying needs some sort of account of intentions, which tends to make things, to my taste, unpleasantly untidy. So, I’m only going to talk about deception instead.

Here’s the way that I think about it. Start with this: the reason organisms respond to sensory information they get from the world is because of the lawful relationship between the information that they receive and the actual properties of the thing being perceived. That is, very roughly, things really are what they seem to be, at least enough of the time. To take one example, the reason that certain fish bite at small, wriggling objects is that, over the evolutionary history of the fish in question, things that were small and wriggled were, with some reasonably high probability, things that were beneficial to eat. This relationship is the key element I’ll focus on: the link between the percept and properties of the object. I’ll refer to it as The Link.

The Link need not have been perfect. Perhaps some small, wriggly things fish encountered were inedible, providing no benefits or even were toxic, imposing some cost. Connecting to my prior post about mice, as long as the expected value of eating entities that were “small and wriggly,” according to the information in the fish’s perceptual array was sufficiently high, then selection would favor continuing to eat things that that were “small and wriggly,” even if the actual outcome sometimes was a bad one.

It goes without saying that if there were some detectable property of the wriggly things that distinguished the good from the bad, evolution could favor more discriminating systems, assuming the cost of the machinery to implement this additional discrimination was lower than the marginal expected value of the additional distinction. That is, if it would be possible but metabolically expensive to add machinery to distinguish small, wriggly prey items from small, wriggly toxic items that did little damage and only rarely were present, selection would have favored the less discriminating, less expensive apparatus.

The Link can be thought of as exploiting, if I may be somewhat Colbertian, truthiness. Because small wriggly things (usually) consist of, as a fact about the world, things that are digestible by the fish, eating them is advantageous for the fish. It’s easy to see that the value of The Link depends on truthiness. If, suddenly, small wriggly things were overwhelmingly harmful to the fish, rather than helpful to the fish, selection would, everything else equal, favor fish who abandoned relying on The Link.

When a given species’ perceptual system exploits a Link, there is potential for other species to manipulate that species’ behavior through systems that produce the stimulus the receiver has been selected to use, taking advantage of the evoked response. So, in the case of the anglerfish, selection can lead to a bit of tissue that produces the stimulus object their prey are designed to use to lure their victims. This bit of the fish’s phenotype breaks the Link, being small and wriggly without having the properties that fish use to feed.

Breaking the Link is how I think deception should be defined. To me, deception occurs when a trait breaks the relationship between stimulus and world that another organism’s phenotype has been designed to exploit. I think this will properly include all the cases that we want to include in the concept, exclude all the ones we want to hold aside, and of course avoid any intentional language. So, in the present case, it seems right that the angler fish’s morphology deceives its prey, violating the usual relationship other fish use to identify prey.

I note in passing that costs and benefits play no role in my proposal here. That is, I don’t insist that cases of deception impose costs on the deceived. Most might well do this, but I leave open the possibility that deception will benefit both deceiver and the deceived. One can imagine cases in which one organism is designed to deceive another organism in such a way that it takes advantage of the Link, but the deceived organism is nonetheless better off or at least no worse off.

So. That’s how I’d define deception. Counterexamples?

06. November 2012 by kurzbanepblog
Categories: Blog | 22 comments