PSY 198: Brain, Mind, and Behavior
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Anxiety and Operational Definitions Assignment

(Modified from Crawford & Christensen, 1995)

In order to ommunicate effectively with others as scientists, we must define our concepts explicitly. This requires several steps. First, we have to have some conceptual idea that we would like to measure. Such a concept is often referred to in psychology as a construct. A construct might be any idea or image created specifically for the purposes of research. In Psychology, the term "construct" generally refers to a collection of related behaviors that are associated with one another in a meaningful way. Some examples of psychological constructs include ideas such as love, depression, frustration, intelligence, hostility, fear, and anxiety.

All of these ideas are of interest to psychologists, but as you might imagine, they are somewhat challenging to study or to measure. Your idea of what constitutes intelligence, for example, might be quite different from mine. If we are going to talk to one another effectively about our interests in this construct, we need to be sure that each of us understands exactly how the other defines the term "intelligence."

Conducting research on a given construct requires that the researcher go beyond the conceptual defintion of the construct he or she is interested in, and develop an explicit operational definition.

To have an operational definition of a construct is to say that you are defining that construct by the operations used to measure it. In other words, it is a definition of the construct in terms of how an investigator proposes to measure that construct. For example, if I say to you that I study stress in non-human animals, you may rightly ask me "And how do you define stress?" After all, a polar bear pacing in its cage at the zoo cannot tell me about whether or not it feels stressed!

One possible operational definition of stress I might use in my polar bear study would be the amount of cortisol (a hormone released when the body is stressed) that the bear has in its bloodstream. Another operational definition of stress I might used is the amount of time the bear spends pacing every day.

Imagine that another psychobiologist is interested in the construct of depression. He or she might operationally define depression in terms of behavioral observations (ex. overall activity level, facial expression, content analysis of speech patterns), or in terms of questionnaires (ex. Beck Depression Inventory), or physiological measures (ex. lateralization of EEG brain wave activity, amount of serotonin metabolites in cerebral spinal fluid). Alternatively, he or she might wish to develop a depressing situation so as to try to induce a state of depression for a particular study; if so, an operational definition of depression would be in terms of the procedure used to produce this emotion (ex. showing a very gloomy film to subjects).

The purpose of this assignment is to help you to understand the development of operational definitions. The construct of anxiety will be used in this case.

Defining the Construct of Anxiety

Anxiety is an emotional state we have all experienced. Since the 1930's, after Freud emphasized its importance, both the psychological and the medical fields have published thousands of studies investigating anxiety. The procedures and stimuli that provoke anxiety and fear in both humans and non-human animals have been studied.

For the first part of your assignment, pause for a few moments and write down your personal definition of anxiety, as if you were writing a book of psychological terms. You can download a copy of the handout we received in class on which to list your definitions by clicking here.

Next, check the various definitions you can find for anxiety in a dictionary. You can use either a regular dictionary, or a dictionary of psychological terms that you might find in the reference section of the library. Write down those definitions that you think might be useful to a researcher.

Bring your work thus far to class with you on Sept. 7th, so you can do the next part of the project in class with your teammates.

On the 7th, discuss the various conceptual definitions of anxiety that your team has discovered. Choose which one your team will use in the rest of this assignment, and write it out in the appropriate place on your assignment sheet. You can download a copy of this assignment sheet here.

As you will probably note, anxiety is a much more complex construct than you may have thought it to be. As a result, the conceptual definition and the theoretical orientation of a researcher can lead him/her down many different paths of research on this topic. The resulting operational definitions of different researchers may be similar, or they may be quite different. The underlying question, of course, is whether or not all of these various operational definitions are in fact measuring the same thing.

As a researcher, it is not enough to have a conceptual definition of a construct. You must now convert that conceptual definition into an operational definition.

With your teammates, brainstorm about some possible operational definitions you might develop for the construct of anxiety. On the appropriate place on your assignment sheet, list at least three ways by which you could measure anxiety at a physiological level. Be quite specific, remembering that your definition must be clear enough so that another researcher could replicate it.

Next, list at least three ways by which you can measure anxiety at a nonverbal., observational level. Specifically, what behaviors and/or conditions of an individual would indicate to an observer that s/he was experiencing anxiety?

Go on to the next part of your assignment sheet and list several ways by which you could measure anxiety through verbal reports. Specifically, what kinds of questions would you ask to determine whether or not an individual was experiencing anxiety? These can be true-false questions, multiple-choice, or open-ended questions.

So far, you have been operationally defining individuals' anxiety responses. Now, list several ways by which an experimenter could experimentally produce anxiety with cetain procedures and/or stimuli. Be sure that what you propose is ethical! Once again, be specific enough to allow anyone reading your definitions and descriptions to be able to replicate your procedure.


The Manefest Anxiety Scale

When you and your team have brainstormed all of your answers, and you have written out your personal responses to the questions on your assignment sheet, go on to the next part of this assignment.

Previously, you and your teammates listed a number of possible operational definitions for anxiety, including those that use self-reports from the individual. For the next part of the assignment, you will fill out one self-report scale that has been used extensively to operationally define anxiety and then you will evaluate the psychometric properties of the scale.

One of the first anxiety self-report scales, the Manefest Anxiety Scale (MAS) was developed by Janet Taylor (1951, 1953). The MAS is concerned with assessing your general characteristic anxiety level over time. The questions on the MAS will be given to you in class (or you can download it here). Answer each statement true or false. Do not leave the answers to any of the questions blank. Be as honest as possible--you will NOT be turning in your answers to these questions. When you complete the questionnaire, score yourself using the scoring key shown below. Give yourself one point for each answer that is the same as that given in the scoring key.


1 F
11 T
21 T
31 T
41 T
2 T
12 F
22 T
32 F
42 T
3 F
13 T
23 T
33 T
43 T
4 F
14 T
24 T
34 T
44 T
5 T
15 F
25 T
35 T
45 T
6 T
16 T
26 T
36 T
46 T
7 T
17 T
27 T
37 T
47 T
8 T
18 F
28 T
38 F
48 T
9 F
19 T
29 F
39 T
49 T
10 T
20 F
30 F
40 T
50 F

When you have calculated your personal score, enter it into the data sheet on the computer at the front of the classroom. DO NOT ENTER YOUR NAME.

Summarizing Class Data

In this study, we are not asking about cause and effect--rather, we are only describing the general state of anxiety of students in this class. Using descriptive statistics, then, we can summarize the class data in several ways:

  • Range: from the highest to the lowest score
  • Mean: the average score
  • Median: the middle score
  • Mode: the most common score

Your instructor will show you how to find these values using MS Excel. Write the values in the appropriate places on your assignment sheet.

Finally, reflect for a moment. Did you like the true-false format of this scale? Why or why not? What other types of responses might you use to answer the same question? Write your answers to these questions on your assignment sheet and turn it in to your instructor before leaving class today.


Crawford, H.J. & Christensen, L.B., (1995). Developing Research Skills: A Laboratory Manual, 3rd Edition.Boston, MA: Allyn & Bacon.


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