Action Patterns (Motor Programs)

Action patterns or motor programs are what used to be called instinctive or innate behaviors. They are shaped by the animal's genetic heritage, "wired in" to the nervous system. In many cases these behaviors can be elicited by direct brain stimulation.

Is a "species-typical" pattern necessarily found only in one species?


Yawning is "species-typical" but not limited to one species

A motor program or action pattern is a distinctive, stereotyped pattern of movement carried out by most healthy members of a species. Such behaviors are species-typical but not unique to one species. Many motor programs are shared by a wide variety of species. Consider yawning. Humans yawn, hamsters yawn, rabbit's yawn, horses yawn. This is an excellent example of a motor program: a stereotyped, built-in pattern of behavior. It is "species-typical" (typical of individual species) but definitely not unique to a species.

The phrases instinctive behavior, innate behavior, action patterns, motor programs and wired-in behaviors have all been used to label species-typical behaviors. Motor program is perhaps the most widely used term now, usually (everywhere but the United States) using the British spelling motor programme.

Because motor programs are genetically based and built into the nervous system, they may persist even when the reason for their existence is gone. For example, declawed cats continue to make claw-sharpening movements that no longer serve a purpose. Well-fed dogs that are raised indoors will "bury" plastic bones in clothes or bedsheets.

What is an isolation experiment and what does it indicate about a behavior?

How does a scientist determine whether a behavior is learned from other members of the species, or hard-wired into the nervous system? The classic technique is to do an isolation experiment. In this type of experiment, a young animal is raised from babyhood in isolation from other members of its species. If a species-typical behavior still emerges under these conditions, then clearly the behavior was not learned from other members of the species, and the tendency to perform that behavior is programmed into the nervous system.

Sometimes an isolation experiment occurs accidentally, when a wild animal is reared from infancy in a human household but species-typical behaviors nevertheless appear.

How do isolation experiments sometimes happen accidentally?

When we talked about animal behavior in class, it reminded me of my roommate's pet squirrel. Cindy has had the squirrel since it was a little baby. He fell out of his nest even before his eyes were open. The squirrel, named Scooter, still shows normal squirrel behaviors even though he has been raised by humans. Cindy made him a little tent by putting two pillows together. Scooter will hide all sorts of toys and food in his house and goes through all the motions of digging a hole to hide his horde in. He loves to run through tunnels and holes and loves to jump from chair to chair. High places are his favorite, e.g. curtain rods and ceiling beams. He rotates his food in his paws before he eats it. Even though he retains these habits, he seems happy in captivity and always runs back to the house after being put outside. [Author's files]

Although the basic form of species-typical motor programs is built into each animal's nervous system, the motor programs of birds and mammals are usually modified by experience. For example, bird song can be modified in complex ways, depending upon what a baby bird hears as it grows up. All mammals learn. By contrast, reptiles emerge from eggs with all their motor programs ready to go. They require no practice.


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