"You sit at the board and suddenly your heart leaps. Your hand trembles to pick up the piece and move it. But what chess teaches you is that you must sit there calmly and think about whether it's really a good idea and whether there are other, better ideas." Stanley Kubrick

Animal behavior

The study of behavior helps us to understand when and why animals, including humans, act. At one extreme, behavior is the link between the nervous system and the world outside an animal. At the other extreme, behavior is the way in which an animal establishes and maintains itself in its ecological niche. Behavior is a key link between an animal and its environment.

Animals behavior includes communication, navigation, foraging, mating, parenting, and social cooperation. Each of these topics is a major subject within the study of behavior, and we will deal with each in a separate chapter. These issues all involve action and interaction; they are the externally expressed component of animal behavior.

Behavior has internal underpinnings, as well. Motivation, learning, cognition and emotion shape an animal's behavioral decisions and therefore are critical in the study of behavior. Each of these topics has a neurobiological basis, so that their study links externally expressed behavior with the internal state of an animal.

In the background, the action of evolution over generations plays a key role in determining behavior. Poor behavioral decisions affect an animal's reproductive output; over time, gene combinations that allow ineffective behavioral decisions disappear from populations. Evolution is the ultimate constraint on how animals behave.

Strategies and tactics for survival

A strategy is a plan of action, in which you define your goals and decide the means by which you'll meet those goals. A tactic is an action, or short sequence of actions, which you use to achieve your strategical goals. What shapes the strategies used by animals to survive? Natural selection plays a key role, favoring successful strategies. Environmental predictability determines whether strategies are hardwired or modifiable through experience. And, a species' sensory and motor tools define its possibilities. Over many generations, natural selection and, sometimes, culture, creates strategical plans for animals. The principles concerning strategical and tactical choices apply to virtually all contexts in which animals behave.

Game theory and behavior

If thou dost play with him at any game, Thou art sure to lose; and, of that natural luck, He beats thee 'gainst the odds

Antony and Cleopatra, Act II, scene 3I

Games may be lost due to luck, but more often we lose due to poor play. Choosing the right strategy (or gaining the winning strategy via natural selection) is the centerpoint of success in either games or life. Shakespeare's character, Brutus, surely does not defy the odds; he better understands the possibilities and outwits Caesar.
By analogy, then, the theory of human games applies to animal behavior. Game theory does not answer all of our questions about animal behavior, but it gives a solid framework in which we can understand the behavioral choices made by animals.
An animal's choice of strategy may be based on genetic background (essentially, information gained by the action of natural selection on previous generations), experience, and/or an assessment of conditions. Natural selection provides a testing ground for strategies; computer simulations allow biologists to simulate the interaction of strategies. A strategy that cannot be dislodged by other strategies is called an "Evolutionarily Stable Strategy", or an ESS.

The prisoner's dilemma is a classic example of how game theory has been used to analyze strategies in animal behavior

Classical ethology

Through much of the 20th century, European and American scientists were sharply divided over how to study animal behavior. European scientists focused on imprinting, innate releasing mechanisms, communication in natural environments, and the development of behavior through animals' lives. Also, ethologists emphasized the value of comparative studies of specific behavioral patterns, such as mating, across species, in order to gain insight into how those behaviors evolved. Americans, mostly working in psychology departments, focussed on learning and conditioned responses. These two divergent approaches, nature versus nurture, led to a chasm in thinking about the relative roles of nature (innate or inherited responses) and nurture (learned or acquired responses) in animal behavior.

The ethologists' approach is well characterized by the four key subjects within the general study of behavior chosen by Niko Tinbergen: Causation, Survival value, Ontogeny, and Evolution. The central value of considering these issues while observing animal behavior is the placement of behavior in a biological context. Other classical ethologists included Konrad Lorenz and Karl von Frisch. Tinbergen, Lorenz, and von Frisch shared the Nobel prize in Physiology or Medicine in 1973 for their contributions to our understanding of animal and human behavior. The last quarter century has brought a blurring of the lines between the American and European approaches to studying animal behavior. Contemporary animal behaviorists combine the biological context, as emphasized by ethologists, with the experimental rigor of comparative psychology. Often scientists apply sophisticated techniques from the fields of genetics, statistics, and mathematical modeling to questions in animal behavior.

Lehrman, D. S. 1953. A critique of Konrad Lorenz's theory of instinctive behavior. Quart. Rev. Biol. 28:337-363.

Tinbergen, N. 1963. On the aims and methods of ethology. Z. f. Tierpsychol. 20:410-433.

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