Partial Reinforcement

Partial Reinforcement

Tamar Rodd

College of Staten Island

Abstract:

A way to test an animal response in extinction is by using the paradoxical reward effects. The one we used in the lab was the partial reinforcement extinction effects. This is the effects that determine the extinction effect, when an instrumental response was reinforced only some of the time. The pigeon was established and maintained on variable ratio (VR) schedule of food presentation. The schedule was then change to a fixed ratio (FR 1) scheduled for a predetermined number of reinforcers. After each component there was a period of ten minute extinction. The sequence was repeated a different number of times for us to determined relation between the amounts of reinforcer delivered during each components and the amount of responses during each extinction. There were fewer responses during extinction in the presence of stimulus recently correlated with the FR 1.

Partial Reinforcement

If an animal respond decline in extinction is due to the frustration from the unexpected absence of reinforcement, then one would expect that there would be more rapid response following extinction causing a greater expectation of rewards. This shows how paradoxical reward effects can affect an animal. The paradoxical reward effect show that the more training that is associated with getting a reinforcer the stronger there would be an expectancy to get a reward and this therefore lead to a stronger rate of frustration will be when extinction is introduced.

The paradoxical reward effect we use in this lab is the partial reinforcement extinction effect. In this effect the characteristic that determined extinction effect is whether the response was reinforced continuously or when it was reinforced partially.

Zarcone, Branch, Hughes and PennyPacker (1997) did an experiment in which the explore this idea. In there experiment there participant was on a multiple variable ratio schedule and a fixed ratio schedule. They conclude that there were fewer total responses during extinction after the Fr than after the VR.

Method

Subject

The subject was a White Carneaux pigeon. The age and sex are unknown. It had participated in other experiments using different stimuli and a different response key. The assignment of this bird to my group in the present experiment was random with respect to its previous treatment. It was housed in an individual cage and maintained at 80% of its free-feeding weights.

Apparatus

The apparatus consist of an enclosure box measuring 11.7 x 55.8 x 66 cm. The view window is 27 x 19 cm and the glass inside of it is 14.2 x 11.5 cm. Inside of the box is an operant chamber which is made out of clear Plexiglas glass; it measured at 31.2 x 37.1 x 38.6 cm. It has a wire grid floor inside of it, it measured 29.7 x 38 cm. The ventilation inside of the box measured 12.5 x 12.5 cm. The food hopper for which the pigeon get its grains from is located on the floor of the chamber measured 4.8 x 7.7 cm.

Procedure

This experiment had two parts to it and it run one week apart. In the first week, it started with a blue (disk) circle behind the key. While this circle was on forty reinforcer was continuously. After the forty reinforcer was