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

Experiment 1: Cup Approach

Purpose:

This is the first of a two-part operant conditioning procedure. The ultimate goal is to train the animal to press the lever by using standard reinforcement principles. Part 1 trains the rat to approach the cup and seize a food pellet. Part 2 will train the animal to press the lever for food.

Procedure:
  1. Do an equipment test .
  2. Notify the TF when you are ready to begin the experiment.
  3. Turn on the house light. You do this by pressing the hand switch once.
  4. Deliver one pellet into the food cup. You do this by pressing the hand switch once. You will notice that the food dispenser will make a click when activated.
  5. Place your rat in the operant chamber and wait for him to find and eat the pellet.
  6. You will now begin 100 click food trials. A trial is considered to start when the pellet is delivered and terminated when the animal seizes the pellet. At no stage should you deliver a pellet when the animal’s nose is in the food cup.
  7. For the first 5 trials present a pellet when the animal appears to be moving towards the cup. You do this by pressing the hand switch once. Press the hand switch a second time as the animal seizes the pellet. The external light will flash.
  8. For trials 6-100 a pellet should be delivered regardless of body position of the animal, but should be given at varying inter-trial intervals averaging 20 seconds. A rough rule is to separate trials non-systematically at inter-trial intervals of 5, 10, 15, 20, 25, 30 and 35 seconds in a continuously scrambled order. The rat should learn to move from any position in the chamber toward the food cup when the pellet dispenser is operated.
  9. Again, a pellet is delivered by pressing the hand switch once. The hand switch should be pressed a second time as the animal seizes the pellet. The external light will flash indicating that the trial has ended and that the ITI has begun.
  10. . When trial # 100 has been completed, the house light will go off signaling the end of the experiment.

Data Collection:

Before coming to class prepare a sheet numbered 1 to 100 and determine the length of the inter-trial intervals for trials 6-100.

During the experiment, you will be recording latencies in seconds for each of the 100 trials. The latency is time from the moment you press the hand switch that delivers the pellet until the animal seizes the pellet and you press the hand switch again. Use a stopwatch that will be supplied to you for purpose of recording the latencies of each trial in seconds.

Group Data:

Submit your group data before leaving class.

 

Latencies for all subjects in your lab section are required.

First Five Trials

Second Five Trials

Last Five Trials

1

2

3

4

5

1

2

3

4

5

1

2

3

4

5
                             

 

Lab Report # 1:

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

  1. Did your subject show a change in latencies for each trial from the beginning of the experiment through to the end?
  2. Would it be easier to detect a trend by using summary data? This could be achieved by dividing the 100 trials into 20 blocks of 5 trials. Is there a change in mean and median latencies from the first block of five trials to the last block of five trials? Is there a change in the variability in the latencies across the blocks of trials?
  3. How does your subject compare to the group? Does he follow the same or a different pattern? Use the data for the first, second and last five trials to depict this.

Statistical Analysis:

  1. Group data analysis. Is the change in latencies statistically significant?

MED-PC Output:

For additional information refer to MED-PC Output Explained .

Array C: Latencies. (Move the decimal two places to the left for the number of seconds.)

Array D: Inter-trial intervals.

Cup Approach Program.