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Tuesday, April 21, 2015

Biological constraints in learning

Biological constraints on learning
Biological constraints on learning refer to any limitations on an organism's capacity to learn that are caused by the inherited sensory, response, or cognitive capabilities of members of a given species. Likewise Biological constraints are limitations on learning that result from biological factors rather than from experience.

An observation that certain behaviors can be learned more easily than some other. It is part of the learning theory in psychology.

BIOLOGICAL CONSTRAINT: "Gorillas and chimps are able to learn different physical tasks and to communicate using the sign language, but due to biological constraint they are not able to learn to read or speak."

How do biological constraints affect classical and operant conditioning?
Classical conditioning principles, we now know, are constrained by biological predispositions, so that learning some associations is easier than learning others. Learning is adaptive: Each species learns behaviors that aid its survival. Biological constraints also place limits on operant conditioning. Training that attempts to override biological constraints will probably not endure because animals will revert to predisposed patterns.

Biological Constraints on Learning
The phenomena that are usually called biological constraints on learning indicated the intrusion of biological factors into standard, traditional conditioning situations. Breland and Breland (1961) were the first to recognize the importance of constraints in operant conditioning situations. They observed what they called instinctive drift, a tendency for "natural behaviors" of animals undergoing operant conditioning to intrude upon and interfere with the emission of the response being reinforced. The Brelands clearly recognized the fundamental importance of their observations, which they viewed as a "demonstration that there are definite weaknesses in the philoso­phy underlying these (conditioning] techniques" (Breland and Breland 1961, 684). However, their findings had little effect at the time. The later discoveries of taste aversion learning, autoshaping, and species-specific defense reactions had more impact.
Taste aversion learning was first reported by Garcia and Koelling (1966). In essence, taste aversion learning suggests that some stimuli are more associable than others, challenging the often implicit assumption of associationists that stimuli are generally equipotential (Seligman 1970). These studies show that many animals are more likely to associate intestinal illness with gustatory (or olfactory) stimuli than with external stimuli. Garcia and Koelling (1966) proposed that these results demon­strate that rats may have a genetically coded hypothesis: "The hypothesis of the sick rat, as for many of us under similar circumstances, would be 'it must have been something I ate'" (Garcia and Koelling 1966, 124).
The phenomenon of autoshaping was first reported by Brown and Jenkins (1968). Brown and Jenkins found that if they simply illuminated a light behind a pecking key for a few seconds, then presented food, the pigeons began to peck the key even though these pecks had no effect on the presentation of the reinforcer. Although they felt that an appeal to some species-specific disposition was necessary, and though Breland and Breland reported many similar findings in less constrained situations, Brown and Jenkins do not cite the Brelands. The implication that species-specific predispositions affect the key peck has been confirmed. Jenkins and Moore (1973) snowed that the topography of the pigeon's key peck depends on the rein-forcer used. Mauldin (1981; Kami! and Mauldin 1987) found that three different passerine species each used species-specific response topologies in an autoshaping situation.
There can be no doubt that these "biological constraints" on learning demon­strate that the evolutionary history of the species being studied can affect the out­come of a conditioning experiment. Whether the differences between taste aversion learning and other aversive conditioning are considered qualitative or quantitative, differences that seem most explicable in functional grounds do exist. The form of the response in a Skinner box depends on the natural repertoire of the animal, as do the results of avoidance learning experiments. However, the impact of these findings on the psychological study of animal learning has been limited.

In summary, then, three types of research indicate the need for a biological approach to learning: (1) studies of biological constraints, which clearly show that the evolutionary history of the species can affect the outcome of conditioning experi­ments in a variety of ways; (2) studies of specialized learning, which indicate that there can be significant variation in learning mechanisms that correlate with the ecologies of the species being studied; and (3) evidence from behavioral ecology, which shows that general forms of learning are of adaptive significance and may also, therefore, vary in ways that correlate with ecology.

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