Monday, October 20, 2008

The Matching Law

Briefly outline what the matching law is and describe two types of deviation from matching.For each of these deviations discuss one factor that may produce that type of deviation.Present experimental evidence that illustrates an application of the matching law (with animal or human participants).

Herrnstein (1961, as cited in Shahan and Podlesnik, 2007) developed matching law.Matching law stated that allocation of instrumental behaviour to two alternatives is proportional to the relative rate of reinforcement retrieved from those alternatives.

The matching law was built on Herrnstein’s own experiment on pigeons. The experiment had a series of conditions where each key was linked with its own schedule of reinforcement. A few reinforcement schedules were occurred simultaneously is named as concurrent schedule. The experiment demonstrated that when two thirds of the reinforcers came from left key, the pigeons also responded around two thirds of the proportions on the left key too (Herrnstein, 1961, as cited in Mazur, 2006).

However, the results of the experiment not necessarily would have followed the matching law. Undermatching and bias are the two types of deviations from matching law. Undermatching means that proportion of responses are less insignificant than reinforcement proportions. A likely explanation about undermatching is that subjects may attribute a reinforcer to the wrong responses due to forgetfulness. (Davidson & Jenkins 1985, as cited in Mazur, 2006). As for bias, it refers to a subject’s response proportions are consistent on one option over the other rather than follow the matching law of equation. Bias may happen when the subject prefers a response key or a certain colour.
Kyonka (2008) examined the effects of reinforcer rate and magnitude, whether responding can be controlled. Four pigeons responded in a concurrent-schedule procedure where reinforce rate and magnitudes changed randomly across sessions. The result showed that the responding within session was comparatively higher when the higher rate and larger magnitude were coupled with the same option than when they were coupled with dissimilar options. Kyonka (2008) concluded that the results support the matching law’s assumptions of additivity and independence as applied to choice in changeover.


References:

Kyonka, E. G. E. (2008). The matching law and effects of reinforcer rate and magnitude on choice in transition. Behavoural Processes, 78, 210-216.

Mazur, J. E. (2006). Learning and Behavior. (6th ed.). Upper Saddle River, NJ: Prentice Hall.