Adaptive theory is the name for theories across several disciplines of science that deal with a system’s ability to adjust itself based on what has occurred before. In some disciplines, the system is self-aware, and theory attempts to explain why it makes the choices it does. Other adaptive theories attempt to explain how an adaptive system that isn’t self-aware still selects for certain conditions.
In biology, adaptive theory is synonymous with natural selection, a chief component of the theory of evolution. Natural selection states that, given a range of traits within a species, those traits that help an individual survive and procreate will become preponderant. The classic example is that of the peppered moth, for which the proportion of light and dark colored moths in the population adjusted to help the moth remain camouflaged as industrial pollution darkened its environment. Another common example is sleep patterns, which are believed to be adapted to the need to remain alert for possible predators. Classical Darwinist theory states that natural selection is the primary means by which one species evolves into a different species, and most non-Darwinists accept that natural selection controls traits demonstrated within a species.
In neurology and in programming, adaptive theory deals with how a learner adapts and reacts to stimuli. It examines how the neural network holds expectations and compares those to actual sensations and stimulations. Neurologists attempt to determine how the human brain operates. Programmers attempt to find ways for computers to duplicate human learning.
In medicine, the Roy Adaptive Theory suggests that the purpose of nursing is to help patients adapt to the situation of their injury or illness. This includes helping to take care of the patient physically and helping the patient adjust mentally and emotionally to any long-term ramifications of his or her condition. The theory is the work of Sister Callista Roy, a professor and nurse theorist at the Boston College of Nursing, and is based in part on the work of psychologist Harry Helson.
Helson’s adaptation-level theory was that individual judgment is a function of prior experience. This common-sense observation has several ramifications. Each individual has unique experiences, so his or her choices might vary from that others would demonstrate in the same situation. Individuals adapt to whatever their current situations are, so everyone tends to view his or her current status quo as normal. Adaptive theory also plays a role in criminal profiling, in which law enforcement officers attempt to predict how criminals will behave based on demonstrated behavior.
Adaptive theory in economics is based in part upon Helson’s work in psychology. Classical economics is concerned with collective decisions and therefore downplays the role of emotions and experiences in individuals’ decisions. Adaptive theory suggests that economic decisions are not based solely on the present but also on expectations for the future, which are, in turn, based on past experiences. For example, classical supply-and-demand theory would state that consumers would behave in a certain way if gasoline prices were $3.50 US Dollars per gallon (3.79 liters). By contrast, adaptive expectations theory indicates that consumer behavior will vary based on whether consumers believe that gas prices are stable, on their way down or on their way up.