Fixed Action Patterns and Their Human Manifestations
All animals function - to some degree - on instinct. From the tiniest slug, to the largest elephant, to the brainiest human; we all are inherently inclined to perform certain behaviors. It's simply hard-wired into our brains.
The simplest form of instinct is a fixed-action-pattern. This is an innate behavior that is triggered by some sort of sign stimulus and - once initiated - will run to completion. One of the best known examples is the behavior of the nesting Graylag Goose. If an egg is displaced from the nest, the bird will reflexively roll the egg back to the nest with its beak. However, Konrad Lorenz discovered that it will complete this action even if the egg is removed during the behavior. The goose will simply continue with the behavior as if the egg was still there.
While scientists are hard-pressed to discover any perfect examples of fixed-action-patterns in humans, all Homo sapiens are born with basic instinctual behaviors. For example, a newborn infant will reflexively grab on to any object that is tendered. Studies have also demonstrated that babies will instinctively grab on to a rope to avoid falling. In addition, newborns have been found to grasp hair more firmly than other objects. This is possibly an evolutionary remnant of behavior that is witnessed in modern-day primates. Neonatal monkeys are hard-wired to hold on tight to their furry mothers.
A possible reason for the demonstrated lack of fixed-action-patterns in humans is that they have been replaced by the onset of culture. Where culture is well-developed, it seems that nurture can almost entirely replace nature. Humans no longer need to rely on instinct to survive, not when we have education, technology, and social norms.
However, one could argue that culture has developed its own version of fixed-action-patterns. For example, when one enters an elevator, he or she will almost inevitably turn and face the doors. Or, when a guest is invited in to someone's home, the host will almost always offer some sort of beverage. Granted, these behaviors are not compulsive, but they are compelled by very strong societal pressures.
While it appears that true fixed-action-patterns are confined to the animal kingdom, there are certain patterns that I wish would cross-over to humans. Many species of infant birds need only to open their squawking mouths to send their parents hurrying off in search of food. I wish that would have worked on my parents.