Book T of C
Chap T of C
This is the 2007 version. Click here for the 2017 chapter 08 table of contents.
Tinbergen and Lorenz emphasized solitary animals or pairs of animals, in their classic work of the 1930s through 1950s. With the 1960s and 1970s came a new emphasis on group interactions of animals, such as competition, communication, and predatory/prey relationships. Predator/prey competition led to specialized adaptations in many animals. Bats are such efficient predators of insects that many insects have adaptations specially designed to help them avoid bats. Other prey animals evolved colors that warned potential predators of a bad taste, or imitated stimuli feared by the predator animal.
A variety of examples show how visual patterns are used by insects to ward off potential predators. Many moths have eyespots on their wings, because birds (which prey on moths) are themselves preyed upon by animals with large staring eyes (like primates, cats, and owls). Birds are highly sensitive to visual patterns but relatively insensitive to the size of a pattern, so visual mimicry in insects works by scaring away predator birds.
Alarm responses are often shared between different species, benefiting all. In the 1980s, researchers discovered that vervet monkeys had at least three different alarm calls for different types of predators-a simple form of communication. Since then, the same phenomenon of multiple, specific alarm calls has been discovered in many species. Humans also participate in shared alarm calls (with watchdogs), and humans themselves have a stereotyped alarm call: the scream.
Struggles for territory and social status are common in group living animals. Monkeys, rams, and porpoises are known for aggressive combat to establish who is dominant. Animals use a variety of signals to avoid damaging combat when possible. Threat displays often involve what Tinbergen called "intention movements." Submission postures are used to indicate deference to higher status animals, in group living species. Appeasement displays are used to calm down a threatening animal.
Prosocial behaviors are friendly interactions of group-living animals. Grooming is one such behavior, often elicited with invitation displays. For example, monkeys turn their backs to other monkeys to elicit grooming. Harry Harlow discovered that baby rhesus monkeys separated from their mothers would cling to a surrogate (substitute) mother made of soft cloth. He said there was a need for "contact comfort."
Most animals have highly developed action patterns devoted to courtship, mating, nest building, and raising the young. Odors are often involved in identifying a home territory, for example, when salmon return to the stream where they were born, for spawning.
Social ethology has generated many concepts that can be applied to humans. The discipline of sociobiology, proposed by Edward O. Wilson in 1975, was very controversial because simplistic references to genetic influences. It reminded people of eugenics, a discredited movement of the late 1800s and early 1900s. However, evolutionary psychology slowly gained credibility, and by the 1990s and 2000s it was a vigorous sub-discipline of psychology. There is ample evidence for the influence of evolution on human behavior, and the ideas of evolutionary psychology can be tested in replicable forms of research.
Evolutionary reasoning applied to human being is tricky for several reasons. Genetic and epigenetic influences are complex and subtle, often involving multiple interactions. Evolved behaviors, once established in a population, may be used opportunistically in new ways that meet different needs. For humans, cultural changes are very rapid, and behaviors that may have been adaptive in ancient times may not be sustainable in the modern world.
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