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Home Up Apparatus Equipment Test Experiment 1 Experiment 2 Experiment 3 Experiment 4 Experiment 5 Experiment 6

Experiment 3: Extinction and Spontaneous Recovery

Purpose:

To demonstrate the extinction of an operant response and the subsequent spontaneous recovery of that response.

Procedure:

Part A – Reinforcement Training

  1. Do an equipment test
  2. Notify the TF when you are ready to begin the experiment.
  3. Turn on the house light by pressing the hand switch. Place your subject in the operant chamber.
  4. Ninety bar presses will be reinforced.
  5. The external light will flash at the end of every minute. You are required to record the number of bar presses per minute and any other behavior that you think relevant.
  6. After the 90th response the external light will flash twice indicating a transition into the next phase. Further responses will not be reinforced.

 

Part B – Extinction

  1. Your subject has now entered the first of three extinction phases. For the purposes of this laboratory, extinction is said to have occurred after 2 minutes of no responding.
  2. Continue to record the number of responses per minute, and any other behavior that you deem relevant.  Note: The external light will flash once at the end of every minute.
  3. After two minutes of no responding, the house light will go off and the external light will flash twice indicating that the criteria for the first extinction have been met. Return the animal to his home cage for 10 minutes. You must time this period of 10 minutes. The program does not time this interval.

 

Part C – Spontaneous Recovery and 2nd Extinction

  1. After the 10-minute period is over, weigh the rat again.
  2. Press the hand switch to turn on the house light. The external light will flash twice. Return the animal to the operant chamber.
  3. Responses will not be reinforced. Continue recording the number of responses per minute. The external light will flash once at the end of each minute.
  4. Once your animal again meets the extinction criteria (two minutes of no responding) the house light will go off and the external light will flash twice.
  5. Return the animal to his home cage for another 10 minutes. Again, you must time this interval.

 

Part D – Spontaneous Recovery and 3rd Extinction

Repeat Part C

The experiment will end when the house light goes off.

Data Collection:

Before coming to class, prepare a data sheet. You will be recording the number of bar press responses per minute.

Group Data:

Submit your group data before leaving class.

 

Number of minutes to….

Number of responses during…

Extinction 1

Extinction 2

Extinction 3

Extinction 1

Extinction 2

Extinction 3
           

 

 

Number of Responses

During the last 5 minutes of bar-press training

1st min Ext. 1

1

2

3

4

5

1
           

 

Lab Report # 2:

You will be required to present the data graphically with a view to answering the following questions:

  1. Did the pattern of bar pressing displayed by your subject change during this experiment? You will be given a computer generated cumulative record of your subject’s responses. Use this to describe what happened during the experiment.
  2. Did the number of responses change during the three extinction phases? How does your subject compare to the group?
  3. Did the time to extinction change for the three extinction phases? How does your subject compare to the group?
  4. How does the number of responses in the last complete minute of reinforcement compare to the number of responses in the first minute of extinction? How does your subject compare to the group?

Statistical Analysis:

  1. Is there a significant difference in the number of responses made during the first, second and third extinction's for the group?
  2. Is there a significant difference in the time to extinction between the first, second and third extinction phases for the group?
  3. Was there a significant increase in the average number of responses in the first minute of each of the three extinction periods?

MED-PC Output

Array A – the number of responses in each of three extinction trials.

Array B – the time to meet extinction criteria for each of three extinction trials.

Array C – used to generate the cumulative record

Array D – the number of responses per minute

Extinction And Spontaneous Recovery Program.