This tutorial corresponds with Module A Lesson 2 and should be completed by students enrolled in Professor Hokerson's Psychology 300 online class at American River College.

1. EXPERIMENTAL RESEARCH
Module A Lesson 2 Tutorial
Created by: Professor Hokerson
American River College
Last Updated: Spring 2013

2. USING THIS TUTORIAL
 Use the navigation buttons to advance through the
slides.
 Complete each slide as instructed.
 Click on hyperlinks when prompted.
 Have fun and learn!

3. TABLE OF CONTENTS
 Objectives
 Module A Objectives #19 -20
 Action Items
 A Comparison
 Experimental Research Design
 Independent Variable
 Dependent Variable
 Creating Groups
 Research Examples
 Identifying Research Examples
 Conclusions

4. MODULE A OBJECTIVES
By the end of this tutorial you will be able to…
# 19 – Explain what makes the experimental
research distinct from correlational and
descriptive designs.
#20– Identify the dependent variable, independent
variable, control group, and experimental group by
reading examples of actual experimental research.

5. ACTION ITEMS

6. A COMPARISON OF RESEARCH DESIGNS
 Descriptive - “Strategies for
observing and describing
behavior”
(Hockenbury, Nolan, & Hockenbury, 2015, p.21)
 Surveys
 Interviews
 Case Studies
 Naturalistic Observations
 Correlational – measures how
closely variables relate to each
other
 Each strategy has its own
strengths and weaknesses!
 “Method used to demonstrate a
cause-and-effect relationship
between changes in one
variable and the effect that is
produced on another variable”
(Hockenbury, Nolan, & Hockenbury, 2015, p.26)
 An experiment requires
intentional manipulation.
 Experiments also have
strengths and weaknesses!
Descriptive & Correlational Experimental Method

7. EXPERIMENTAL RESEARCH DESIGN
 Read: Chapter 1 – The Experimental Method
(pages 26 – 30)
 Tip! Researchers choose this method for one
reason…
 To show cause – and – effect!
 Summary: Experiments must have all these
components:
 Independent Variable
 Dependent Variable
 Experimental Group
 Control Group

8. THE INDEPENDENT VARIABLE
A is the variable that will produce a change in B.
 Definition: variable that is intentionally manipulated by the
researchers
 It is the focus of the study
 Tip! There must be an independent variable or it cannot be an
experiment. Remember that this method attempts to describe a
causal relationship between two (or more) variables.
 Conclusions: An experiment can produce two results:
 There is a causal relationship (A did change B)
 There is no causal relationship (A did not change B)

9. THE DEPENDENT VARIABLE
A is the variable that will produce a change in B.
 Definition: variable that is measured in response to the
independent variable
 Tip! An experiment cannot determine the effect of Variable A if
its effects are not measured. Therefore, B (the dependent
variable) measures those effects.
 Conclusions: Dependent variables look a lot like descriptive
methods:
 Surveys and questionnaires
 Behaviors that are observed and recorded
 Computer generated activities and games

10. CREATING GROUPS
 Tip! To conclude cause-and-effect the researcher
must expose some of the subjects to the
independent variable
 The researcher also needs to have a group of subjects
that are not exposed to the independent variable
 This is the manipulation!
 Caveat: The simplest design has 1 experimental group and 1
control group, but there are many studies in which there are
more than 2 groups!

11. EXPLANATION OF EXPERIMENTAL DESIGN
Subjects are randomly assigned into either the control or experimental group.
The experimental group
receives the IV…
…the control group proceeds directly
to the dependent variable OR receives
a placebo first.
Both groups complete the dependent variable.
Tip! If you cannot find these 4 components then you are reading descriptive
or correlational research and can never, ever, ever conclude cause!
Subjects
Experimental Group
Independent Variable
Control Group
Dependent Variable

12. RESEARCH EXAMPLES
 Read: Here are some actual research examples:
1. A study reported that babies and infants that watch programs
geared toward enhancing intelligence use fewer words than their
non-program watching cohorts.
2. A longitudinal study reported that factors such as motivation,
creativity, and willingness to work hard are predictors of
academic success.
3. A study reported that antidepressant use by adolescents can
increase the risk of suicide
 Caution: There are still many considerations to be made
about these studies. Don’t draw any conclusions yet!
 Review: There are other research considerations to explore:
 Ethical Considerations – pages 34 - 35
 Sampling issues – page 23
 Replication and Validity – page 19

13. IDENTIFYING RESEARCH METHODS
 Question: How do you know if what you are
reading is descriptive, correlational, or experimental
research?
 Tip: Decision Making Tree
1. Do any of the conclusions say “cause”?
2. Are the subjects intentionally split into groups?
3. Do the subjects all do the same thing?
 Activity: Complete the Research Examples
Worksheet to practice differentiating between
descriptive and experimental research.

14. EXPERIMENTAL DESIGN CONCLUSIONS
 Only an experiment can conclude cause-and-effect.
 Researchers intentionally manipulate these studies.
 Any other type of research is either descriptive or correlational.
 Experiments are highly controlled.
 Subjects are randomly assigned into different groups.
 Experiments are often conducted in labs or other unnatural
settings.
 You should always walk away from research with more questions
than answers.
 How can the results apply in other settings?
 Who were the subjects?
 Can any other variables explain the results?

15. MODULE A OBJECTIVES
After completing this tutorial you should be able
to…
# 19 – Explain what makes the experimental
research distinct from correlational and descriptive
designs.
#20– Identify the dependent variable, independent
variable, control group, and experimental group by
reading examples of actual experimental research.