Starlings and Optimal Foraging Theory: Modelling in a Fractal World

Abstract

Whether the optimality approach to the study of behavior is a respectable scientific theory has often been the subject of debate (Maynard Smith 1978; Gould & Lewontin 1979; Gray this volume; Ollason 1980 and this volume). The argument is partly obscured by the semantic difficulties associated with the use of the term “theory” and its difference from “model” and “hypothesis.” Behavioral ecologists must be concerned with this debate because it is important to establish the relationship between theoretical statements and empirical evidence and to be aware of what is being tested when biological data are compared with theoretical predictions. It is also important to determine the relative advantages of alternative research programs. Differences in outlook between authors belonging to various schools of behavioral research are common. While one occasionally reads statements such as “optimality theory predicts (or fails to predict) the observed results,” thus implying that it is the theory itself that is under experimental test (Mazur 1981; Diamond 1984; Fantino & Abarca 1985; Mellgren & Brown in press; Rashotte in press), evolutionary zoologists interested in behavior usually maintain that optimality itself is not being tested, but rather that specific models derived from the theory are (Maynard Smith 1978; Curio 1983; Kacelnik 1984; Cheverton, Kacelnik & Krebs 1985; Schmid-Hempel, Kacelnik & Houston 1985).

“Consider for instance one of the white flakes obtained by salting a solution of soap. At a distance its contours may appear sharply defined, but as we draw nearer its sharpness disappears… The use of a magnifying glass or microscope leaves us just as uncertain, for fresh irregularities appear every time we increase the magnification, and we never succeed in getting a sharp smooth impression…” Perrin J. 1906.