This project is about opening up the cognitive world of another organism to study and understanding. Before we get too far along, an important ground rule is in order. While I will unabashedly invoke hypothetical constructs that can also be applied to human cognition, labeled by terms such as “representation,” “computation,” “decision-making,” “emotion,” and the like, I am also going to be extremely careful about how I use and define such terms. This is important even for the study of human cognition, to which these terms may first have been applied, but it is even more important for the study of animal cognition. One reason for caution is that a surface similarity between two things (say, something an animal can do and something people can do) is not evidence that they are caused by the same underlying process. Another reason is that in nature, in general, the way things actually work is often simpler than might appear, and it is reasonable to assume that cognitive abilities of animals are simpler than those of human beings, even when the behavior they mediate is superficially similar.
This notion that things may be simpler than they appear is a foundational principle in science. The principle goes very various names: the Parsimony Principle, Ockham’s Razor, etc. Scientists use it all the time explicitly or implicitly. (So, by the way, do car mechanics, forensic investigators, and historians, if not conspiracy theorists or ufologists.) The basic idea is to prefer the simplest possible explanation for a given phenomenon, unless the evidence forces you to accept a more complex explanation. This general principle is embraced not as a simple article of faith, but because it is a good guide to understand–things are often simpler than they appear. However, they are not always simpler in they way we think they are, and sometimes they are not simple at all, so the parsimony principle by itself is not enough.
An aside on Ockham’s Razor, named after the theologian William of Ockham (c. 1287 – 1347). I looked Ockham up in the Stanford Encyclopedia of Philosophy, and learned two interesting things. One is that the most common formulation of Ockham’s razor does not actually appear in his writings, although the underlying sentiment does. That common formulation goes, “entities must not be multiplied beyond necessity” (entia non sunt multiplicanda praeter necessitatem). According to Wikipedia, that formulation was written not by Ockham but by one John Cork in 1639. However, Ockham did write something very similar: “Plurality is never to be posited without necessity” (Numquam ponenda est pluralitas sine necessitate). The more interesting thing I learned in the Stanford Encyclopedia of Philosophy article had to do with Ockham’s criteria for determining when we would have positive evidence for affirming the existence of things. He gave three criteria, saying, “For nothing ought to be posited without a reason given, unless it is self-evident (literally, known through itself) or known by experience or proved by the authority of Sacred Scripture.” What intrigued me about this is that in some cases what we know because it is self evidence or by experience may contradict the authority of Sacred Scripture, so retaining all three of these criteria seems a violation of Ockham’s Razor. Perhaps Ockham couldn’t have known how thoroughly experience (i.e. science) would come to undermine the truth claims of Sacred Scripture about how the world works.
Back to ethology and cognition. A version of the parsimony principle was articulated by an early student of animal behavior, Conwy Lloyd Morgan, in reaction to the anthropomorphic theories advanced by some of his predecessors. Often known as Lloyd Morgan’s Canon (or simply Morgan’s Canon), this goes as follows: “In no case is an animal activity to be interpreted in terms of higher psychological processes if it can be fairly interpreted in terms of processes which stand lower in the scale of psychological evolution and development.” Morgan’s Canon greatly influenced the development of the sciences of animal behavior during the 20th century, especially in psychology. Indeed, it was only with great reluctance that psychologists in the middle to late 20th century allowed themselves to speculate about cognitive processes that might intervene between the stimuli impinging on the animal’s sense organs and the responses that the animal produced. In the extreme, the “radical behaviorists” such as Watson and Skinner claimed that hypotheses about cognition were untestable and hence unscientific. As we shall see, this proved incorrect. To be fair, it was not entirely unreasonable to doubt that one could make inferences about unobservable mental processes on the basis of the stimuli and responses that could be observed and measured. However, the evidence, won through the ingenuity of experimental psychologists (of humans as well as animals), has allowed the rigorous testing of hypotheses about mental phenomena.
Another foundational principle shaped the thinking of the zoologically trained European scientists who invented the field of ethology. In fact this principle is central to this whole project of trying to enter the world of the honey bee. The principle is the Umwelt concept, which was developed and applied to animal behavior by Jakob von Uexküll. This is the notion that each animal inhabits its own, species-specific subjective world, perceiving just those features that matter to its existence, and producing just those actions that matter for its survival. (As an aside, the word “Umwelt” is one that means “environment” in German, but it is not the only one. “Umgebung” is also used. In fact, Umgebung was the word, found in Goethe, that was rendered in English by Thomas Carlyle as “environment.” See discussion here about how this happened. I find it intriguing that English, a language with Germanic roots, couldn’t just borrow the German word intact rather than inventing a word with French roots, but I suppose that reflects the politics of nationalism and cultural envy.)
In any case, the original formulation of the Umwelt concept by von Uexküll contained a principle of parsimony regarding the complexity of the processes underlying the responses of animals to the environment. But it was more a descriptive than a normative principle: von Uexküll was making a claim about the way the world is rather than about the logical necessity of this reality. In particular, he argued that one could explain apparently complex behavior in terms of a simple set of reactive mechanisms. The Umwelt concept, as it is described in many animal behavior text books, is equated to the idea that animals live in their own species-specific perceptual worlds, which may not be identical to our perceptual world. This is indeed an important part of the story, but it is only half of the story: the Umwelt of an organism encompasses not only the perceptual world, or Merkwelt, but also the “effector world,” or Wirkwelt, the set of actions that it is capable of performing. Beyond this, an animal’s Umwelt is organized into what von Uexküll called “functional cycles,” which von Uexküll considered fundamental units of behavior. Each functional cycle consists of a simple perceivable feature of the environment and the action that it “releases” (to use the term adopted by later ethologists). It is the identification of a simple set of functional cycles underlying apparently complex behavior that shows the Umwelt concept to be a parsimony principle.
The example that von Uexküll used to illustrate this concept is the ability of the common tick to “hunt” for mammalian prey. This might be regarded at first glance as a complex behavior, whereby the female tick positions herself strategically in a location where prey might pass, then leaps onto them at the right moment and then navigates to a part of the body suitable for biting and sucking on blood. Von Uexküll suggested that it can be explained by positing just four functional cycles: first, the animal senses gravity and climbs upward in vegetation and then stops; second, it waits for the smell of butyric acid, a common component of mammalian body odor, which causes it to drop; third, tactile contact with fur releases crawling; fourth, warmth (from contact with skin) releases biting and sucking. If the tick misses at step two or is brushed off at step three, then it just starts at step one. This is a highly impoverished Umwelt: the predator’s entire “knowledge” about mammals is represented by three stimuli: the smell of one chemical, the touch of fur, and warmth. But, as von Uexküll said, “the very poverty of the world guarantees the unfailing certainty of her actions, and security is more important than wealth” (von Uexküll 1934).
One of von Uexküll’s critical insights is that we need to view the animal as the subject as well as the objects of the processes that cause it to behave the way it does. Adopting this stance requires us human observers to unshackle our imaginations from the constraints of the very rich Umwelt that we inhabit. It requires an act of imagination to picture what it might be like to be a tick (or a bee). Often the Umwelt of a given animal will turn out to be simpler than might appear, as in the case of the tick and many other species studied by the early ethologists such as Niko Tinbergen.
But simpler does not merely mean that an animal’s Umwelt is a reduced or stunted version of the human Umwelt. In fact, ethologists have discovered that animals may be capable of responding to sensory stimuli which to us are completely undetectable by our sense organs or are meaningless even if we can sense a crude tingling in the presence of the stimulus. Examples are the ability to detect polarized light in blue sky (most insects and arthropods), electrical fields (several groups of fish and also bees), magnetic fields (several bird species), ultraviolet light (most insects and many birds), infrared light (pit vipers), ultra-high frequency sounds (bats and some birds), ultra-low frequency sounds (elephants). Furthermore, quite apart from merely sensing such stimuli, what animals do with the information they contain boggles the mind–at least it boggles my mind. Three examples: the ability of pigeons to navigate home after being displaced to an unfamiliar location a thousand kilometers away; the ability of a bat to emit ultrasonic chirps and then analyze the returning echos to chase down and capture flying insects; the ability of a honey bee to measure the distance and direction of a flower patch (even if she has flown an indirect path to get there), then fly home and report this in movements of her body we call the dance language.
Adopting the Umwelt concept has been liberating in another way; it has enabled the elucidation of how different animal species may interact when their sensory worlds overlap. An example is the realization, in the 1990s, that many birds analyze each other’s plumage by integrating across ultraviolet as well as visual wavelengths. This led to the realization that what is bright to our eye may not be bright to a bird’s. In an earlier, and even more dramatic example, the discovery that bats hunt their prey using echolocation in the ultrasonic frequency range was followed by the discovery that many insects (including some moths, lacewings, and mantids) can hear these calls and undertake evasive escape maneuvers. As I wrote in an earlier review of this topic, “Thus, the Umwelten of predator and prey interlock in a grim ballet set to a score that only the dancers can hear” (Dyer and Brockmann 1996).
Bats, with their dazzling ability to live in a world of sound, have played a disproportionate role in illustrating the Umwelt concept. And it is no coincidence that they served as the straw man (there, I said it) in Nagel’s argument for the futility of knowing the nature of other minds. But that’s a topic for another day.
Dyer, F.C., J.A. Brockmann. 1996. Orientation, sensory processes, and communication. In: Foundations of Animal Behavior (Ed. by L.D. Houck and L.C. Drickamer). Chicago: University of Chicago Press.
Uexkull, Jakob von 1934. Streifzuge durch die Umwelten von Tieren und Menschen. Berlin: Springer-Verlag. (Translated as: A stroll through the worlds of animals and men, in C.H. Schiller, ed., Instinctive Behavior, pp. 5-80. New York: International Universities Press ).