Research Methods
for the digitally inclined
by
Stephen R. Schmidt

Learning Objectives for Test 3

I. Key terms (From Chapters 4, 9, 10, 11)

II. One question from each of the following groups will appear on the test. (Relevant readings are listed in parentheses. Also look at the on line notes.)

1. Subject Variables (Ch 10)

What are some of the challenges in studying the influence of dispositional variables on human behavior?
A researcher was interested in how vocabulary changed with child development. He recruited students from first and sixth grades in a local elementary school, and then gave the children a vocabulary test for two kinds of words: abstract words (e.g., "thought"�) and concrete words (e.g., "computer"). He found there was a larger difference in vocabulary across grades for the abstract words than for the concrete words. What kind of design is this? Define any independent and dependent variables in this design. What potential problems do the researcher have to consider when interpreting my results? How could he avoid these problems?
A researcher compared memory performance of depressed versus non-depressed students. She recruited students from Intro. Psych, gave the students a depression inventory, and then, based on their scores, assigned the participants to either the depressed or the non-depressed group. She then read each group a list of words, and measure the number of words recalled. Depressed students were found to have poorer memory than non-depressed students. What kind of design is this? Define any independent and dependent variables in this design. What potential problems do she have to consider when interpreting my results? How could she avoid these problems?
Describe the major difficulties of interpreting the effects of subject variables in an experimental design.

2. Within and Between Subjects Designs (Ch 9 & 10)

Compare and contrast within and between subjects designs, noting their various strengths and weaknesses.
Design an experiment to compare the effects of two reading programs (A versus B) on learning to read in the first grade. Decide whether it is better to use a within- or a between-subjects design and describe why you think this is the appropriate choice of experimental design. Describe your selection of research participants, and the assignment of participants to conditions.
Imagine I am studying perceptual processes, and I want to determine what factors influence the subjective loudness of a tone. I will need to run a large number of trials, comparing subjective loudness of tones varying in intensity, frequency, and duration. Should I use a within or a between subject design? Why?
What are "carry-over"� effects in experimental designs? Give an example.

3. Factorial Designs (Ch 9)

I am conducting a between subjects factorial experiment to determine the impact of three different drugs on the behavior of ADHD children. I am comparing these drugs separately for a male and a female sample.

a) Describe the design in terms of the number of factors and the number of levels of each factor:

b) How many groups of subjects do I need to complete the experiment: ____.

c) Show me what the design looks like in a table.

I am conducting a between subjects factorial experiment to determine the impact of three different text books on learning statistics. I am comparing these books using two different instructors, with each instructor using each book in a different section of the course.

What is an interaction in factorial design? How does it influence the experimental interpretation? What does it look like graphically? (Ray Campanion Site, pp. 177-182)
What is the difference between a main effect and an interaction effect in a factorial design? What do researchers mean when they say a main effect is compromised by an interaction?

4. Ethics (Ch 4)

Who decides whether or not a research project is ethical? What standards are employed?

Consider the following research proposal. What ethical principles are not being followed? What could the researcher do to make the study more ethical?

This research was concerned with eyewitness identification. The experiment was conducted in a fast-food outlet during regular operating hours. All employees were carefully rehearsed regarding a staged crime. As customers entered the outlet, they were asked to participate in a research project in exchange for a free drink with their order. If they agree to participate, they are then asked a few simple questions about their food preferences. The experimenters waited until the food outlet only contained people who had agreed to me in the research. Then a "crime" was committed by an actor who entered the store displaying an unloaded handgun and demanded all the money from the cash register. He tells the employees not to call the police and, in making his getaway, shouts to the customers "the first one out the door is going to get blown away." Directly after the "thief" leaves, the researcher and his associates enter the store with a questionnaire that is distributed to the patrons. Each patron is debriefed concerning the nature of the experiment and the relevance to social issues.

I may give you another research scenario, and ask you to evaluate the ethics.
Discuss the difference between informed consent and educated consent.
Describe the two major guiding principles used to judge the ethics of a research project.

5. The Ecology of Experimentation (Ch 11)

What is meant by the "ecology of research?" Describe two majors factors that contribute to research findings resulting from "ecological" interactions.

What is meant by the "social context of truth?"

What are demand characteristics? How can they be minimized in experimental settings?
Describe how the participant can be a source of bias in the research process.
Describe how the experimenter can be a source of bias in the research process.
What is the placebo effect and how can it be minimized?

Last Modified 9/02/2008