Discriminating between stimuli that differ in magnitude

What is it about?

Discrimination learning, simply put, is learning to respond differently to different stimuli (things). Psychologists often study how this happens by conducting behaviour experiments with animals. In these experiments, the stimuli are often qualitatively different (imagine receiving reward on observing a red cube but not on observing a blue sphere). This article does not consider this type of stimuli. In a discrimination based on magnitude, the same stimulus (e.g. a tone) is presented at two different magnitudes (e.g. loud or quiet) and an outcome, such as food, is signalled by one magnitude but not the other. Our review shows these discriminations are acquired more readily when an outcome is signalled by the larger rather than the smaller of the two magnitudes.

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Why is it important?

This finding is important to consider because it challenges a common assumption of learning (that thing A is as similar to thing B as thing B is to thing A) and theories of discrimination learning founded on this assumption. We present an updated mathematical model of discrimination learning to explain this important finding.