Psych 210 (Fall 2013)
Classical Conditioning
Psychology 210: Learning
Assignment #1 Lab Manual
Fall Term topic: Classically Conditioning a Salivary Response in Dogs
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Psych 210 (Fall 2013)
Classical Conditioning
Manual Index
Background info
Key terms to understand
Starting the program and conducting the experiments
How to analyze your data
Writing an APA lab report
How to graph your findings in APA format (step-by-step guide)
Grading rubric
Checklist – make sure you have everything listed before you pass in your assignment on November
22nd
Plagiarism Policy
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Classical Conditioning
Lab Experiment: Classical Conditioning of a Salivary Response in Dogs
In this project, you will perform a computer simulation of classical conditioning of a
salivary response in dogs. The experiment is not carried out with real dogs but involves
computer simulation of the data one might obtain if the experiment were actually done. The
computer simulation is based upon Pavlov's pioneering experiments and contemporary
knowledge of the laws of classical conditioning.
In Pavlov's experiments, a dog was placed in a harness and a cannula or tube was
inserted into the duct of the salivary gland. The strength of the salivary digestive response then
was measured by the number of drops of saliva produced at a given time. Classical conditioning
involved the presentation of a conditioned stimulus (CS), which was initially a neutral event
(called a neutral stimulus) such as a light or a tone. A short time after the presentation of the
CS, a second stimulus, called the unconditioned stimulus (US) was presented. The US was meat
powder and elicited the unconditioned response (UR) of salivation. The critical discovery made
by Pavlov was that after several paired presentations of the CS and US, a dog would salivate
when the CS was presented without the US. A new association had been learned. This new
learned response was called the conditioned response (CR) and became stronger as more
paired presentations of the CS and US were given. The growth in the strength of the CR with
repeated reinforcements from the US is called acquisition.
One purpose of this project is to allow you to obtain trial by trial acquisition data for
classical conditioning and to use those data to plot acquisition curves. A second purpose is to
allow you to discover those conditions of the conditioning experiment that lead to different
rates of acquisition. You will manipulate a number of the conditions or variables under which an
animal or group of animals will be tested. These independent variables (IV) are the number of
acquisition trials, strength of the tone (CS) in decibels, the strength of the US in number of food
pellets given, length of the interstimulus interval (ISI) between the onset of the CS and the
onset of the US, and finally the interactions between the CS, US and ISI. It is assumed that after
each acquisition trial in which the CS and US are paired, a test is given in which the CS alone is
presented to determine what the strength of the CR is after the most recent CS-US
presentation. The data given by the program are the number of drops of saliva (dependent
variable) produced by a given subject on each test trial.
Key Words:
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Classical Conditioning: Eliciting a desired response from an organism via the presentation of a stimulus
not naturally associated with that response (CS), through repeated pairings of that stimulus with one
that does naturally produce the desired response (US).
Unconditioned Stimulus (US): The stimulus that naturally evokes the desired response (e.g. food)
Conditioned Stimulus (CS): Initially called a “neutral stimulus”, this is the stimulus that prior to training
does not naturally evoke the desired response (e.g. the bell) but after training elicits the conditioned
response (CR).
Unconditioned Response (UR): The response naturally elicited by the presentation of the US (e.g.
salivation caused by the food).
Conditioned Response (CR): The response elicited by the CS presented alone (e.g. salivation caused by
the sound of a bell) once conditioning has occurred.
Interstimulus interval (ISI): The amount of time passing between presentation of the CS and US. Note:
The CC program calls this the CS-US interval, so it will be referred to as such in this document.
Acquisition Trials: Pairings of the CS and US to strengthen the association of the two.
Extinction Trials: Continued presentation of the CS alone, weakening the association.
To Start the Program:
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Go to "MY COMPUTER" and then click on "APPS ON ‘CAESAR’ (S:)"
Once there:
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Double-click on the "Psych210" folder. Then double-click on the "cc" icon.
Follow the instructions below to carry out the experiment. To run another experiment, press the "F2"
key. Note: I’ve noticed on some computers this command doesn’t work. You can just close the program
and open it again to start a new experiment.
IMPORTANT:
Once you run your first experimental condition, the program will ask you to press "1" and hit
enter to save the results to your H: drive. The program saves the results in a file called "Cc". BEFORE
you run another trial, you MUST first minimize the Classical conditioning screen (by clicking on the bar in
the top right corner) and double click on the "My Computer" icon and then on the icon for your H: drive.
Once there, rename the "Cc" file to something appropriate (e.g. “Experiment 1 – condition 1 – 10 AT”).
If you do not do this, your second trial data will overwrite your first trial data. Be sure to use
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comprehensive file names outlining which condition the data pertains to. This makes graphing the data
much easier. Once you rename the file, bring the Classical Conditioning program back up and press "F2"
(or close the program and open it again) to run another experiment. Once completed, repeat the same
steps to rename this file before moving on.
Experiment 1
The program will first ask for your name. Type in your name and then press the RETURN key. It
will then ask you how many subjects from 1 to 4 you wish to test. Indicate “4” subjects and press
RETURN. You will then be asked how many acquisition trials you wish to run. For Experiment 1, this will
be our manipulated variable. You will run five conditions in which you will vary the number of
acquisition trials. Condition one will have 10 acquisition trials, condition two will have 20 acquisition
trials, condition three will have 30 acquisition trials, condition four will have 40 acquisition trials, and
finally condition five will have 50 acquisition trials. After indicating the number of acquisition trials, the
program will ask you to indicate how many extinction trials, type in 50 in all conditions. You will then be
asked to indicate the strength of the CS from 50 to 100 decibels, the strength of the US from 1 to 10
food pellets, and the length of the CS-US interval from 0.1 to 1.0 seconds. For Experiment 1, keep the CS
at 50 db, the US at 7 pellets, and the ISI at .5 for all five conditions.
Experiments 2, 3, and 4:
These experiments all use the following parameters:
Indicate “4” subjects and press RETURN. You will then be asked how many acquisition trials you
wish to run. Indicate 50 trials. When asked to indicate how many extinction trials, type in 50 again. After
specifying 4 subjects, 50 AT, and 50 ET, you will then be asked to indicate the strength of the CS from 50
to 100 decibels, the strength of the US from 1 to 10 food pellets, and the length of the CS-US interval
from .1 to 1.0 seconds. These values will be manipulated differently in each experiment.
Experiment 2
The strength of the CS will be varied in the first experiment to find out how CS intensity affects
conditioning. First, test 4 dogs with the CS set at 50 decibels, the US set at 5 food pellets, and the CS-US
interval set at 0.4 seconds. Then test four more dogs at a CS intensity of 60 decibels, with US strength
and CS-US interval held at 5 pellets and 0.4 seconds, respectively. Finally, test four more dogs at a CS
intensity of 80 decibels, with the other two variables held at the same values as used previously. You
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Classical Conditioning
should obtain three printouts, with acquisition data for four dogs tested at each of the three settings of
CS intensity.
Experiment 3
Next, carry out the same type of procedure but vary US intensity and hold CS intensity and
CS-US interval constant. Conduct three experiments with 4 dogs each, with the CS intensity set at 70
decibels and the CS-US interval set at 0.5 seconds. Vary the US intensity across the three sets of dogs,
setting it first at 4 pellets, then 6 pellets, and finally 8 pellets.
Experiment 4
Next, you are to test three sets of 4 dogs at three lengths of the CS-US interval, with the CS and
US intensities held constant. Use a CS intensity of 80 decibels and a US intensity of 6 food pellets. Vary
CS-US interval over three times, 0.3, 0.5, and 0.7 seconds.
Data Analysis and Presentation
You have now tested four dogs under each of the experimental conditions and you have group
data for each condition. To summarize these data, means are given in the right hand column of each
saved data file. The mean is the sum of the number of drops of saliva produced by all four dogs on a
given trial divided by four. You can then plot acquisition curves for the groups of dogs tested under each
condition by plotting mean drops on the y-axis against acquisition trials on the x-axis.
Construct five graphs in APA format (using Excel). If you’re unfamiliar with APA format and making
graphs in Excel, follow the instructions here.
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On the first graph, plot five separate acquisition curves, one for each acquisition value (10, 20,
30, 40, & 50) in Experiment 1. Differentiate the curves by using different symbols at each data
point, and make sure that these symbols are connected by a line to create the curve. Put a
legend on the graph to indicate the CS intensity corresponding to each symbol and follow APA
format.
On a second graph, follow the same procedure but plot the extinction curves for each
acquisition value (10, 20, 30, 40, & 50) for Experiment 1.
On the third graph, plot three separate acquisition curves, one for each value of CS intensity in
Experiment 2. Differentiate the curves by using different symbols at each data point, and make
sure that these symbols are connected by a line to create the curve. Put a legend on the graph
to indicate the CS intensity corresponding to each symbol and follow APA format.
On a fourth graph, follow the same procedure but plot three acquisition curves for each value of
US intensity for Experiment 3.
On a fifth graph, plot three acquisition curves, one for each length of the CS-US interval for
Experiment 4.
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You do not need to plot the extinction trials for Experiments 2-3, however you may want to in order aid
in your discussion. *Please Note: even though you do not have to include an APA graph of the
extinction trials, you are still required to interpret them in your Discussion Section.
Writing an APA Full Lab Report
In this experiment, one variable was manipulated while the others were held constant. Each
student must write a full lab report discussing classical conditioning, the method of the experiment, and
a discussion of each graph. The acquisition and extinction curves that were plotted should be compared.
Refer to the psychology department’s APA manual if you have not written a full lab report
before. It contains detailed formatting instructions and fully explains the purpose of every section of a
lab report. I have a template for this specific assignment up on my webpage to help you get started.
Your lab report should include all of the sections of a full APA lab report, with the exception of an
abstract. Your lab report should include:
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Title Page
Introduction
Method
Results
Discussion
References
Figures
Below is a brief list of material you should be sure to cover in each section of your lab report.
Introduction
- The introduction starts off more general (first describing the topic, then covering past research)
and gets more specific (the current problem under investigation), covering your specific method
and hypotheses in the final paragraph(s).
- Description of the problem(s) or questions under investigation
- Review the previous research in this area, focusing on Pavlov’s work and method.
 You can cite your text and any other resources you require.
- Explain all the concepts involved in the experiments (acquisition, CR, etc.).
- Outline your experiments and explain your hypotheses for these experiments:
 Describe the method very briefly. (The next section will describe it in more detail).
 Explain what is being tested – what are you manipulating in each experiment?
What conditions are there? Be sure to outline the dependent and independent
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Classical Conditioning
variables. Remember that the independent variable changes for each
experiment.
Your hypotheses should be developed from past research. Given what you know from
studying Pavlov’s research, you should have predictions for each experiment in this
assignment. Think about what you expect to happen before you look at your data
output and jot down some notes to refer to when writing your introduction.
Justify your hypotheses with references to past research.
Method
The method section should be very detailed. Remember that you’re supposed to provide the reader
with sufficient information to replicate what you did. There are 3 subsections in the method section:
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Subjects (note: the participants in these experiments are not human so you can use the term
‘subject’)
 Describe the kind of subjects we used (e.g. virtual dogs) and the number of subjects
 4 dogs in each experiment – 14 experiments  56 virtual subjects
Apparatus
 Describe the Classical Conditioning program in detail. Be sure to mention any other
materials used to complete the experiment (Computer, keyboard, etc.) …
Design & Procedure
 Outline how the experiments were conducted, step-by-step. This requires a lot of detail
too! Some things to remember to mention:
 How did you open the program?
• How did you save?
• What information did you provide the program?
• What did you do with your data once you obtained it?
Results
- Describe the findings in simple, straightforward sentences. You should provide the overall range
of means for each experiment. This may be in a Table that you refer the reader to, or in written
description (follow APA guidelines).
- Describe and summarize the graphs created from raw data printouts. Explain what each curve
looks like
Discussion
- The first thing to write about is whether or not your hypotheses were supported. Explain how or
how not.
- Discuss the results in relation to past literature and theory. Here you can mention about what
you wrote about in the introduction. How do your experimental results relate or compare to
Pavlov’s?
- Explain how and why manipulations affected acquisition and extinction.
- Discuss some implications of your findings.
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Outline some limitations of the study. What would you change to improve the study?
Some additional questions to guide your discussion section:
1. Were your findings in line with your hypotheses? Why or why not?
- Remember you had hypotheses for each of the four experiments.
2. What are the general shapes of the acquisition and extinction curves for both experiments?
3. How did variations in the number of acquisition trials affect conditioning and extinction?
4. What number of trials produced the best conditioning?
5. How did variations of the CS, US, and ISI affect conditioning and extinction?
6. What were the most effective experimental parameters for each manipulation in Experiments 2-4?
Why?
References
There are no required readings other than chapter 7 in your text book, so that may be the only
entry in your reference section. However, if you feel that you need to use other academic sources in
your introduction and discussion, you may do so. All sources must be cited properly in the body of your
report and you have to create an entry in your reference section for everything cited in the body of your
report.
Figures
Your five graphs should appear on figure pages after the reference section. There is a section
below instructing you on how to prepare an APA graph and how to format your figure and figure
captions.
Making an APA Graph in Excel
Note: For simplicity, my example uses the data for 10, 30, and 50 trials from Experiment 1. Your graph
should include all 5 conditions.
**A student has pointed out that the APA Manual the psychology department posted states that axis
labels for APA graphs should not be bolded. Bolded axis labels are consistent with the newest APA
(6.0) guidelines. When you add axis titles in Excel they’re bolded automatically, so keeping with this is
the simplest strategy. I will not dock APA points for axis-labels that are not bold, however, due to this
inconsistency in rules between sources.
Data Entry:
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1. Open Excel.
Go to ‘Start’ menu, ‘Programs’, ‘Microsoft Office’, then, ‘Microsoft Office Excel’.
2. Enter your data labels across Row 1.
Your labels should be descriptive of what you manipulated. They should be clear and to the point. The
picture below shows labels that would be appropriate when making a graph to show the effect of
manipulating the number of Acquisition Trials.
3. Input your data.
One at a time, open the data file in your H drive that corresponds to each label (e.g. open the file where
you set the Acquisition Trials at 10 first).
In each data file, you are only using the very last column of numbers (the average drops of saliva). For
your Acquisition graphs, you will take the last column from the top half of each of your data files. For
your Extinction graphs, you will take the last column of numbers from the bottom half of your files.
To quickly copy and paste just that last column, do the following:
In the data file, highlight all of the Acquisition and Extinction data. Click your mouse before the
word Acquisition at top left of file (don’t highlight info above this), and drag mouse across and
down to the bottom right corner at the end of the CC file. Right-click and Copy.
In a blank Excel sheet (“scrap sheet”) right-click and paste all of the data. You are now able to
highlight just the last column of numbers. Again, right-click and copy. You will have to do this
twice for each CC file: First, you drag and highlight the means for Acquisition Trials and paste
them to your working file, and then you return to your scrap sheet and do the same for
Extinction means.
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Move to your working Sheet, and with the cell below the appropriate label selected, right-click
and paste.
Repeat for each data file, separately copying and pasting your Acquisition and Extinction data.
You can organize your Working Excel file like this, or however you prefer:
Making the Graph:
4. Insert Line with Markers Graph.
First, highlight your headings and data for Acquisition, go to ‘Insert’, and select ‘Line’ above ‘Charts’. In
the drop down window, select the chart type that is the second one down in the first column (called
“Line with Markers”).
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5. A graph similar to this will appear in your working sheet.
6. Add Axis Labels.
Select ‘Layout’ up at the top, and then select ‘Axis Titles’. For the Primary Horizontal Axis, select ‘Title
Below Axis’. Type in “Acquisition Trials” if you have graphed Acquisition Data, and “Extinction Trials” if
you have graphed your Extinction data. For the Primary Vertical Axis, select ‘Rotated Title’. Then type in
“Mean Drops of Saliva” every time.
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What to do with your graphs:
You can copy your graphs into Word and edit them for appropriate APA format, or you can continue
editing them in Excel and copy and paste them once they’re finished.
Formatting your Graph in APA style in Excel:
7. Delete Gridlines. Right-click on the gridlines, and select ‘Delete’.
8. Change the font of your axis titles from Bold to Regular.
9. Change Font. Right-click outside the borders of your graph, and change the font to ‘Arial’, size 12.
10. Move Legend and give it a Border. Click on your legend and drag it within the border of the graph.
Once moved, right-click on your legend, select ‘Format Legend’, and under ‘Border Color’, select ‘Solid
Line’ and choose the color black.
11. Remove Border of your Graph. Right-click outside the borders of your graph, select ‘Format Chart’,
and under ‘Border Color’, select ‘No Line’.
To Present a Graph in an APA paper:
13. Copy and Paste your Graph into a Microsoft Office Word file.
14. Underneath provide a Figure Caption. You should refer to each Figure somewhere in your paper.
Each graph should be on its own page with a figure caption.
There is a sample figure page on the following page.
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Mean Number of Saliva Drops
30
25
20
15
10 Trials
30 Trials
10
50 Trials
5
0
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49
Acquisition Trial Number
Figure 1. Drops of saliva during acquisition as a function of number of acquisition trials.
Psych 210 (Fall 2013)
Classical Conditioning
Grading Rubric for Lab Assignment #1
*Must include a title page in APA format and a reference page
______ (20 pts)
Introduction
Summarizes relevant published research in the area of Classical Conditioning
and shows how this research relates to the present experiment. Hypotheses,
the variables that were manipulated (independent and dependent), and what
behaviour was measured should be described. Appropriate readings and
research (i.e., textbook) must be incorporated. The introduction starts off more
general (covering past research) and gets more specific (covering your
hypotheses at the end).
______ (15 pts)
Method – 3 subsections
Subjects: Four computerized dogs/condition
Aparatus: computer, computer program, printer, excel for graphing, etc
Procedure: Fully describes all relevant steps in the experiment in such a
way that another experimenter could perform the experiment in the same
manner. It must be very detailed.
______ (35 pts)
Results
The means obtained for each variation must be presented in a comprehensive
manner, appropriately summarized in graphs, which are referred to and
supplemented by the written text of the results section. Graphs must be
presented in APA format. Data printouts must be included in an Appendix. Just
report the findings, do not interpret (interpretation follows in discussion).
______ (20 pts)
Discussion
Results must be explicitly stated in their relation to hypotheses. Findings
presented in the results section must be related to what was previously
discussed in the introduction. That is, the results must be related to the
literature and any theory involved. This section should discuss why the results
turned out the way they did, as related to your introduction. That is, you should
discuss how the variation affected conditioning and extinction (and why),
referring to your acquisition curves/data printouts. Moves from specific to
general.
______ (10 pts)
Writing Style / APA format
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Instructor’s judgment on whether the experimental design was carried out
correctly, whether the report went beyond the basic requirements, APA etc.
*Rubric is subject to reasonable change
Checklist
Your final assignment should include (in order):
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Title page
Introduction
Method
Results
Discussion
References
APA figures – your 5 graphs
Raw data printout (attach as an appendix at the back of your report)
Plagiarism Policy
Your lab assignments MUST include appropriate APA citations and references to any
information used from the text, journal articles, etc.
Plagiarism (failure to properly cite and reference material, and/or failure to change into your
own words) will result in grade deductions of 40% to 100%, and you will be reported to the Office of the
Registrar. Do not copy parts of your lab report directly from the text, this manual, or any other sources
you may use. A good general rule for paraphrasing is that you should never have a string of more than
three words identical to a string of more than three words in your source material (unless it is a proper
name). Also beware of mosaic plagiarism. Make sure your report is written in your own words. You can
consult the Academic Calendar for more information. If you think you may have problems paraphrasing
source materials, or using APA citations properly, please see me before you submit your assignment. I
can help you identify these problems in your writing and show you how to avoid them.
All reports are to be written up individually. Copying your lab report or even portions of your lab
report from one of your classmates will result in being reported to the Academic Discipline Committee
and similar grade deductions.
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