The Zombie Ant: Parasitic Fungi and Behavior Manipulation
Biology 342 Fall 2014
Tinbergen's Four Questions
In his 1963 paper “On aims and methods of Ethology” Nikolaas Tinbergen defined four major categories for explanations of animal behavior: mechanism, adaptive value, ontogeny, and phylogeny. Current scholars typically separate these into "proximate" and "ultimate" causes. Tinbergen's four questions provide a comprehensive, logical approach to studying behavior that is particularly useful for in-depth analysis.
Proximate Causes (Mechanism and Ontogeny)
Mechanism is the physiology of behavior. Tinbergen referred to this as “causation.” These include the mechanistic explanations of why various aspects of an animal’s physiology function and how those aspects contribute to behavior. For example, identification of hormones and neurotransmitters that contribute to behavior would fall into this category.
Ontogeny describes how behavior develops over an animal’s lifetime. “Innate” is not the opposite of “learnt”; rather, it is the opposite of “environment-induced.” Many behaviors are some combination of innate and learnt (or, in more conventional terms, a combination of nature and nurture). Consequently, as an animal interacts with the surrounding environment over its lifetime, its behaviors change as well.
Ultimate Causes (Adaptive Value and Phylogeny)
Adaptive value describes how a behavior contributes to an animal’s lifetime reproductive fitness. Tinbergen referred to this as “survival value.” Tinbergen asserted that behavior is analogous to physiological characteristics; consequently, behavior, like physiology, has evolved as a means for survival.
Phylogeny describes how a behavior has evolved. Tinbergen referred to this as “evolution.” Over evolutionary time, selective pressures alter the behavior of an animal, much like how selective pressures alter its physiology. The study of phylogeny involves the comparison of closely related species, the investigation of the behavior of different species in the same environment, and the study of selection on the evolution of behavior.
Figure 2. Diagram of Tinbergen's four questions, divided by object of study and level of question. Source: Bio 342 2012 website