Biological Bases

Learning is a process by which experience produces a relatively enduring change in an organism’s behavior or capabilities. It is measured by changes in performance and can be viewed as a process of personal adaptation to ever-changing life circumstances.

For a long time, the study of learning went down two largely separate paths, guided by two different perspectives on learning: behaviorism and ethology.

Behaviorism

Behaviorism focused on how organisms learn, and examined the processes by which experience influenced behaviour. Behaviorists assumed that laws of learning existed that applied to virtually all organisms. For example, each species they studied responded in predictable ways to patterns of reward and punishment. They treated the organism as a tabula rasa, or blank tablet, upon which learning experiences were inscribed. They explained learning solely in terms of directly observable events, and avoided speculating about an organism’s unobservable “mental state.”

Ethology

Ethology focused on animal behaviour within the natural environment. Ethologists viewed the organism as anything but a blank tablet, and argued that, because of evolution, every species comes into the world biologically prepared to act in certain ways. They focused on the functions of behaviour – particularly its adaptive significance, which asks how a behavior influences an organism’s chances of survival and reproduction in its natural environment.

Ethologists called instinctive behavior a fixed action pattern – an unlearned response automatically triggered by a particular stimulus. Further research uncovered two things: 1) some fixed action patterns could be modified by experience, and 2) in many cases, what appeared to be “instinctive” behavior actually involved learning. The differences among species lay not so much in how they learned, but in what they learned in order to survive.

The Role of the Environment

Behaviorism and ethology have increasingly converged, reminding us that the environment shapes behavior in two fundamental ways: through personal adaptation and through species adaptation.

Personal adaptation occurs through the laws of learning, and results from our interactions with immediate and past environments.

Species adaptation occurs through the process of evolution, when environmental conditions faced by each species help shape its biology. This does not occur directly, so that learned behaviors are not passed down genetically from one generation to the next, but natural selection does mean that genetically based features that enhance a species’ ability to adapt to the environment – and thus survive and reproduce – are more likely to be passed on to the next generation. As characteristics influenced by those genes become more common, they become part of a species’ very “nature.”

Every organism’s environment is full of events, and the organism must learn

  • which events are, or are not, important to its survival and well-being;
  • which stimuli signal that an important event is about to occur; and

· whether its responses will produce positive or negative consequences.

Habituation is a decrease in the strength of a response to a repeated stimulus, and may be the simplest form of learning. It allows organisms to attend to other stimuli that are more important.

Biology and Learning

An animal’s evolutionary history prepares it to learn certain associations more easily than others. This principle is called biological preparedness, and shows that there are biological constraints on learning.

It is difficult to operantly condition animals to perform behaviors that are contrary to their evolved natural tendencies. Such conditioned behaviors are often abandoned in favour of a more natural response, a concept called instinctive drift.

Various brain regions and chemicals regulate learning. Environmental experiences affect brain development and functioning, which in turn influences our future ability to learn.




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