Table of Contents
Prac 1: Classical Conditioning of an eye-blink 3
Prac 2: Operant Conditioning – Investigating the Effectiveness of Different Schedules of Reinforcement 7
Prac 3: Application of Operant Conditioning: Shaping 11
Prac 4. Does Observation enhance One’s Ability to Learn a Simple Task? 14
Prac 1: Classical Conditioning of an eye-blink
Source: Grivas, J., Letch, N., Down, R., & Carter, L. (2010). Psychology: VCE Units 3 & 4 (4th Ed). Melbourne: Macmillan Education. Pps 457 – 459.
Classical conditioning of the eye-blink reflexive response is perhaps the most thoroughly studied form of classical conditioning of mammals over the past 100 years or so. For example, as shown in figure 10.7, it has been used in rabbits. Note the use of electronic devices to produce an eye blink (by delivering a puff of air) and to accurately record the reflexive response (by using an electromyograph to detect electrical activity of muscles). What is most important about eye-blink conditioning is that in most cases it appears similar across species, and thus results found in one species can reasonably be expected to apply to others (Gluck, Mercado & Myers, 2008)
This practical activity enables you to apply classical conditioning procedures in conditioning an eye-blink response using a simpler apparatus than that shown in figure 10.7. The two stimuli that will be paired to create a conditioned eye-blink response are:
• a puff of air (blown through a drinking straw and directed at the bridge of a participant’s nose)
• a tapping sound (made by your knuckle or a pencil on a table).
You are to work in groups of three. One person will be the experimenter, one person will be the participant, and the third person will observe and record the participant’s responses. The three group members will take it in turns to apply the conditioning procedure as it is outlined below. The experimenter and the participant should sit on opposite sides of a table within reach of each other. The observer should sit next to the experimenter with a clear view of the participant. The activity is best undertaken in a place free from distractions such as external noise and other people. The procedure has three stages.
Stage 1
Pre-conditioning. The experimenter should tap the pencil several times at irregular intervals without presenting the puff of air. This is done to get the participant habituated to the tapping alone so that they no longer respond by blinking. When the participant shows no sign of blinking to the tapping alone, the experimenter can begin conditioning.
Stage 2
Conditioning. There will be a total of 25 trials. In trials 1 to 15, first present the tapping sound, then immediately blow a puff of air through the straw, aiming at the bridge of the participant’s nose. The tap and air-puff pairings should be presented at irregular intervals within a time period of about 90 seconds. This allows an average time of just 3 seconds for each trial. In trials 16 to 25, present only the tapping sound (i.e. no air-puff) for the five trials asterisked in Table 1. If the participant blinks in all of these five trials then the response can be said to be conditioned.
Stage 3
Post-conditioning. Tap without the air puff several times at irregular intervals until the eye-blink response no longer occurs (is extinguished).
Results
Table 1 Individual data recording sheet
Trial no. Eye-blink response (Y/N)
Trial Number / Participant 1 / Participant 2 / Participant 31
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16*
17
18*
19
20
21*
22*
23
24*
25
Participant 1 Participant 2 Participant 3
*Tapping sound alone presented on these trials.
Analysis and interpretation
1 Construct an operational hypothesis that could be tested by this practical activity.
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2 Compare your data with those of your two partners. Combine the class data and evaluate it in terms of theoretical expectations.
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3 In what sense can a control and an experimental condition be seen in trials 16 to 25?
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4 Represent the combined class data in Table 2.
Table 2. Class Data for Conditioned Eye blink Experiment
Trial Number / Percentage that Blinked / Percentage that did not Blink1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16*
17
18*
19
20
21*
22*
23
24*
25
Participant 1 Participant 2 Participant 3
*Tapping sound alone presented on these trial
5 Describe the results evident in the combined data.
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6 What is the purpose of presenting the tapping sound alone for five of the 25 trials?
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Why are these five trials scheduled towards the end of the 25 trials?
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7 Identify the UCS, CS, UCR and CR in the procedure used for this activity.
UCS: ______
CS: ______
UCR: ______
CR: ______
8 What conclusion(s) can be drawn from the results obtained from this experiment?
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9 Identify and explain any extraneous variables that might have influenced the results.
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10 Explain how the experimental design could be modified to minimise or control the extraneous variable(s) referred to in question 9.
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Prac 2: Operant Conditioning – Investigating the Effectiveness of Different Schedules of Reinforcement
Source: Milesi, P. (2011) The Psych Book VCE Units 3 & 4: Activities, Outcomes and Assessment 4th Ed). Australia: Nelson Cengage Learning Pty Limited. Pps 148-150.
Schedules of reinforcement refer to the manner and frequency in which a desired behaviour is reinforced. Responses may be randomly reinforced and unpredictable in nature (occurring after a variable set of responses) or predictable when reinforcement occurs after a fixed set of responses. Furthermore, reinforcement may occur after set or random time intervals. The different schedules of reinforcement are listed below and their effectiveness in establishing and maintaining desired responses is discussed.
· A continuous reinforcement schedule is effective in rapidly establishing a desired behaviour; however, it has a low resistance to extinction.
· A fixed-ratio schedule of reinforcement is most effective during the acquisition stage of learning, as it establishes a consistent pattern of reinforcement. After the behaviour is established, the frequency of reinforcement may be extended.
· A variable-ratio schedule of reinforcement is highly effective in establishing a learned response, and has a high resistance to extinction, as the individual is always anticipating the reinforcer.
· A fixed-interval schedule of reinforcement is moderately effective in establishing a response, and responses are inconsistent in nature. This is because the individual learns when the reinforcer is due, and thus will cease responding immediately after reinforcement. He or she may only recommence the behaviour when he or she senses that the next time interval is approaching.
· A variable interval schedule of reinforcement is more effective than a fixed-interval schedule as reinforcement is unpredictable. Such a schedule provides a low, consistent, responding rate and therefore has a gradual extinction rate that falls below that of a fixed-interval schedule.
AIM
The aim of this experiment is to measure the effectiveness of the different schedules of reinforcement, and to determine which schedule is the most resistant to extinction.
1. Formulate an operational hypothesis based on the information in the introduction and aim.
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2. What is the IV ______
3. What is the DV ______
Method
Materials:
· A jar of chocolate buttons or jelly beans to be used as positive reinforcers.
· Data recording graph
· Timer
· Two pens /pencils (different colours)
Procedure:
The desired response to be demonstrated by the participant is to recite the alphabet backwards
Step 1. Divide participants into four groups. Each group will receive a different schedule of reinforcement. The correct response rate of the above task over a 10 minute time period will be recorded, and the resistance to extinction measured.
Within the four groups, participants are to work in groups of three with one person acting as the ‘experimenter’ and the other as the ‘participant’. The third person is to observe the participant’s responses and plot the cumulative number of correct responses and periods of reinforcement on the data recording graph.
The exercise should be carried out with both the experimenter and participant seated opposite one another at a desk, with the observer seated adjacent to them.
Group 1 is to be reinforced using a fixed-ratio schedule of reinforcement. (A reward should be given after the correct response has been demonstrated 3 times)
Group 2 is to be reinforced using a variable ratio schedule of reinforcement. (A reward should be given after ever three correct responses on average)
Group 3 is to be reinforced using a fixed-interval schedule or reinforcement ( A reward should be given every 60 seconds precisely).
Group 4 is to be reinforced using a variable ratio schedule of reinforcement. (A reward is to be given every 60 seconds on average)
Step 2. During the acquisition phase of the learning process, continuous reinforcement will be given until some learning has occurred. The participant should recite the alphabet backwards 5 times and receive a reward after each correct response.
Step 3. The experimenter-participant pairs should then commence partial reinforcement with their allocated schedule over a 10-minute time period. On the data recording graph, the observer should chart (by placing a dot) every time the ‘participant’ elicits a correct response over the 10-minute period. A dash in a different colour should also be pencilled in on the graph whenever the experimenter gives the participant a reinforcer.
Step 4. Collate the class results and compare the different schedules of reinforcement.
Figure 1. Correct Responses by subject for reverse alphabet recall
Discussion
1 Based on the results obtained, was the hypothesis supported?
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2 Which partial schedule of reinforcement was the most effective in terms of the speed with which the response was acquired?
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3 Which reinforcement schedule seemed t be most resistant to extinction? Measure this by observing which schedule produced the highest number of cumulative responses over the time period.
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4 Which reinforcement schedule produced the most steady, consistent response rate? Suggest a reason for your answer.
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5 Which reinforcement schedule produced the most erratic response rate (i.e. the participant’s rate of response increased and decreased intermittently over the time period)? Suggest a reason for your answer.
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6 Was the reinforcer used an effective incentive for the participant? If you answered no, explain how this may have confounded the results of the experiment.
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Prac 3: Application of Operant Conditioning: Shaping
Source: Grivas, J., & Lawrie. P. (1991). Psychology Experiments and Activities. Sydney: Harcourt Brace Javanovich. Pps 199 & 200.
An important principle of instrumental or operant conditioning is called shaping. Shaping involves the reinforcement of a response that takes the organism closer to a particular behaviour, to the exclusion of other behaviours. This is similar to the ‘hot and cold’ game, where something is hidden and another person has to find or identify it. There is no feedback other than ‘hotter’ or ‘colder’ as the person gets closer or further away from the desired object.
Shaping has traditionally been studied with rats. There are obvious problems with using rates in a classroom. Consequently this experiment involves two volunteer students, acting as ‘experimental rats.’
AIMS
1. To demonstrate how behaviour can be shaped by rewarding successive approximations
2. To illustrate principles of instrumental/operant conditioning
PROCEDURE
Step 1 Ask for two student volunteers to act as ‘experimental rats’. Have them leave the classroom and remain out of ‘ear range’. While they are out of the room, have the class decide on a novel behaviour for the participants to perform (but do not tell the participants what it is). For example it could be as simple as picking up a book or touching the board. Alternatively, it could be a more complex behaviour such as selecting a specific book from a bookcase or cleaning the board in a particular way.
A group of students (the rest of the class) should call out the word ‘cheese’ whenever the participant makes a positive move in the direction of the required task or goal behaviour.
Discuss the procedure fully, as it is crucial to the success of the activity. As each participant moves about the room, she or he will make many responses. The ‘shapers’ must identify the appropriate responses and reinforce these. Incorrect use of reinforcement will confuse the participant. It is important that the participant can associate the desired response with the reinforcer. Appoint one or more students to time the participants. Record the time taken for each participant to perform the required task.
Step 2 Bring the first participant just inside the classroom and give her or him these instructions: “In your new role as an ‘experimental’ rat you may explore your new environment, groom yourself, listen to strange noises, smell strange smells and generally potter about. You are required to complete a task but will not be told what it is. Instead, you will receive a verbal reinforcement – the word ‘cheese’ – whenever your behaviour indicates a move towards the task’s completion”.
Step 3 Ask the participant to begin exploring the environment. The timekeeper should record the starting time. On each occasion the participant does something that is related to the desired behaviour, the group or class should give the reinforcement by calling out ‘cheese’. At first, it will be necessary to reward the participant for simply looking in the right direction. Also, for learning to most effective, the reward must be presented almost simultaneously with the appropriate response. When the participant actually performs the desired behaviour, call ‘goal’ and stop timing. Record the time taken in Table 1
Table 1. Shaping DATA Sheet
Participant / TimeTrial 1 / Trial 2 / Difference
1
2
Step 4 Return the participant to the starting point. Repeat Step 3. Record the time taken in Table 1.