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Anatomy of a Controversy: The Question of a "Language" Among Bees. Adrian M. Wenner and Patrick H. Wells. Columbia Univ. Press (1990). ISBN 0-231-06552-3. 399 pp. $55 (cloth).
Wenner (and later Wells) are noteworthy as critics (beginning in the 1960s) of von Frisch's interpretation of the "dances" of honeybees in conveying information about the location of food sources (see also Wenner 1971). They contend that bees find food exclusively by odor--a hypothesis, they note, that von Frisch himself once embraced. Especially given more recent studies on the bee's recruitment of foragers (see Kirchner and Towne 1994), their account in this book of the extended controversy deserves note--by biologists and non-biologists alike.
Wenner and Wells' are not unbiased in their interpretation of the debate. However, they offer an interesting scheme for interpreting how scientists apply different approaches to research, often at different times in the history of a theory or conceptual model. First, they say, is `image creation'--the "discovery" of a novel explanation. Next, researchers seek to `verify' their explanation by seeking supportive evidence. Researchers do not always consider, however, the possibility of `falsification', a third approach. Here, one deliberately attempts to generate negative evidence, sometimes using a null hypothesis as a guide. Failing to falsify may lend some further credibility to one's model, but given a particular theoretical orientation, one may easily fail to design a truly rigorous test. "A giant stride toward further understanding" is made only with `strong inference' or the `method of multiple working hypotheses' (Chamberlain 1965). That is, one must consider alternative explanations and design experiments to confirm one model while simultaneously disconfirming another. Science is best, they say, when it employs all four methods.
Too often, they claim, emotional attachment or social processes interfere and hold researchers in the `verify' mode. This, they contend, was what happened in the debate over the bee dance language. When Wenner conducted what he considered a properly controlled study in the early 1960s, his negative evidence was mostly ignored. Subsequently publication of his views and his rebuttals to criticism were suppressed, his research grants were denied, and so forth. (Yes, one can detect more than a hint of bitterness in this account--and find plenty of passages that serve little function beyond merely the airing of grievances.)
What is so intriguing and so telling about Wenner and Wells' version of the controversy is the tension between their claims about proper scientific method and their own practice. Emotional involvement and interpersonal biases are ubiquitous in science, they claim, and they use this fact to "expose" the conceptual entrenchment of their critics and their "failure" to move beyond the narrow `verify' mode. At the same time, of course, they claim the objective "high ground" for themselves. They do not consider their general principles with respect to themselves, nor recognize their own theoretical commitments and how they shape their own interpretations of experiments. The account, like so many in scientific debates is distinctly asymmetrical (consider also next book below).
Wenner was originally puzzled by how the bee "dances" could be effective in the complete darkness of a hive (von Frisch had observed them in a glass-walled hive so, of course, he could see them!). At one point, Wenner (and another researcher, Harald Esch) suggested that sound was an important element in the communication. Later, Wenner advocated a role for odor, noting several observations about wind direction and bee flight patterns. In subsequently promoting the odor hypothesis, however, Wenner has also excluded any role for the dance-like behavior. Wenner did identify several ways in which von Frisch's early experiments were inadequately controlled. Though he was criticized at the time, many of his controls have been incorporated into further studies.
--Which all leads to the current state of affairs (see, for example, the article in last June's Scientific American). According to Wolfgang Kirchner, working in Denmark, honeybees learn about remote sources of food through a hybrid process. First, returning foragers dance, drawing the attention of other bees by a sound produced with their wings. Possible recruits attend to the sound of the "waggle" dance with organs in their antennae, acquiring information about the distance of the source. At the same time, they presumably get information about direction from their orientation to the dancing bee. The potential recruits then lower their thoraxes on the honeycomb surface, sending an impulse which prompts the "dancing" bee to stop. Samples of the food are then offered, supplying information about odor, taste and quality of the source. Recruits may then fly out to look for the source. This is consistent with a second alternative, documented by Wenner and Wells, that a recognizable odor itself can prompt a "veteran" to return to a previously visited source. The dance pattern does not occur unconditionally or mechanically. Tom Seeley (at Cornell Univ.) has found that only returning foragers with the highest loads are prompted to dance, as determined by `receiver bees' that can compare various loads. Nor does every bee following a dance become a recruit. Again, an individual bee compares possible food sources from different dances and from its own experience outside the hive. There is a complex, somewhat loose system of selection, by which the best sources generally tend to be conveyed and then chosen. Nor do all foragers that follow a dance find the respective source. One may well presume that the odor information and the flight patterns observed by Wenner are important in isolating the location of a source, once the bee is downwind or in (what should be) the general locale. This apparent solution to honeybee recruitment--involving movement, sound, and odor--is more complex than anticipated by either von Frisch or Wenner. And that may be a general lesson about science.
One underlying problem that plagues Wenner and Wells--and that they fail to recognize--is that evidence that supports one hypothesis (while not "supporting" another) does not always serve as direct counterevidence for other hypotheses. They must assume that the alternatives are exhaustive and mutually exclusive--and often they are not. Their model of science also assumes that theories are simple and static entities that can be either proven or refuted, often by a single well designed experiment. Instead, theories can be fluid and are often revised to fit new findings. Wenner and Wells present such a caricature of von Frisch's hypothesis that they take any revision merely to prove the hypothesis "wrong." Controversies in science often pose challenges for the interaction of theories. Typically, each theory or model has some positive evidence not addressed by other theories. Single "crucial" experiments are often logically impossible. Instead, researchers must work creatively to find ways to accommodate the theories with each other or to differentiate the specific scope of each. That, apparently, has been the physiology of this controversy in the long run.
Readers will find that the authors' hard-edged orientation dominates the book and obscures their message. Still, there is a wealth of information, here, for delving into this controversy. Particularly valuable are a number of sections and "excurses" (in appendices), where some of the technical arguments and data are available--a good resource for helping students to hone their skills in designing or interpreting experiments. One will find how a well-controlled experiment can become invalidated as new ideas arise. The science, here, is far more complex and engaging than the short accounts of von Frisch's hypothesis that one finds in textbooks. It is a classic case, well suited for teaching.
The prospective reader should also approach this book aware of its stylistic problems. The writing is convoluted. Terms are used with distinctive meanings that are not explicitly defined but only become apparent after repeatedly anomalous usage. A `test', for example, does not mean any kind of experiment, but specifically one which includes a null hypothesis or falsifying design. To `confirm' does not mean to `verify': the later is used to mean collecting supportive evidence, the former is used to mean `testing' (in its special sense). To `infer' does not mean to reason or induce, but (only) to conclude from a crucial experiment where one decides among alternative hypotheses. That should give a flavor of the difficulties in reading "plain" text.
From Wenner and Wells perspective, I suspect, I would be placed among those they dismiss--as someone deeply enamored of the dance language hypothesis (or anthropomorphically fond of the notion of those clever honeybees). But I was fascinated by the prospect of seeing a "proven" hypothesis wholly unwind--and, indeed, I picked up the book expecting as much. But even with a sympathetic ear, I was unconvinced by the evidence. Hm. The authors do nicely clarify in their philosophical scheme (above), how several models of science need not compete with each other, but coexist in different contexts. Would that they could transfer this observation to the scientific models of honeybee behavior.
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