1. FUNDAMENTAL RESEARCH ISSUES
CHAPTER 4
FUNDAMENTAL RESEARCH ISSUES
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2. LEARNING OBJECTIVES
Compare and contrast nonexperimental and experimental research methods
Distinguish between an independent variable and a dependent variable
Discuss the three elements for inferring causation: temporal order, covariation of cause and effect, and elimination of alternative explanations
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3. LEARNING OBJECTIVES
Discuss the limitations of laboratory experiments and the advantage of using multiple methods of research
Distinguish between construct validity, internal validity, and external validity
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4. Qualitative vs. Quantitative
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5. OPERATIONAL DEFINITIONS OF VARIABLES
Variable is an abstract concept that must be translated into concrete forms of observation or manipulation
Studied empirically
Help communicate ideas to others
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6. Research Methods
Descriptive studies: A descriptive study is one in which information is collected without changing the environment (i.e., nothing is manipulated).
- survey method
- naturalistic observation
- case studies
- correlational method
 Example, in descriptive studies, variables are not discussed using the terms "independent" or "dependent." Instead, the names of the variables are used when discussing the study.  For example, there is more diabetes in people of Native American heritage than people who come from Eastern Europe.  In a descriptive study, the researcher would examine how diabetes (a variable) is related to a person's genetic heritage (another variable).
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8. FOUR TYPES OF RELATIONSHIPS BETWEEN VARIABLES
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9. RELATIONSHIPS BETWEEN VARIABLES
Positive Linear Relationship
Increases in one variable relate to increases in another
Negative Linear Relationship
Increases in one variable relative to decreases in another
Curvilinear Relationship
Increases in one variable relative to both increases and decreases in another
Included U-shaped and Inverted U-shaped curves
No Relationship
Correlation coefficient
Relationships and Reduction of Uncertainty
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10. Ice Cream Sales vs Temperature
The local ice cream shop keeps track of how much ice cream they sell versus the temperature on that day, here are their figures for the last 12 days
Ice Cream Sales vs Temperature
Temperature °C
Ice Cream Sales
14.2°
$215
16.4°
$325
11.9°
$185
15.2°
$332
18.5°
$406
22.1°
$522
19.4°
$412
25.1°
$614
23.4°
$544
18.1°
$421
22.6°
$445
17.2°
$408

11. Correlation example
You can easily see that warmer weather leads to more sales, the relationship is good but not perfect. The correlation is

12. There has been a heat wave
There has been a heat wave! It gets so hot that people aren't going near the shop, and sales start dropping.
The correlation calculation only works well for relationships that follow a straight line. The calculated value of correlation is 0. But we can see the data follows a nice curve that reaches a peak around 25° C. But the correlation calculation is not "smart" enough to see this
If you make a Scatter Plot, and look at it, you may see more than the correlation value says.
Make your own scatterplot

13. Measures of Central Tendency

14. Measures of Central Tendency

15. Non-Experimental Research Methods: Case Studies
Single subject or small group
Each studied individually and in depth
Data gathered using:
Direct observation
Questionnaires
Testing
Experimentation
Case studies have investigated the relationship between sexually violent media and rape. In many of these studies, rapists report high levels of exposure to sexually violent films, magazines, and books. However, it is unclear whether violent attitudes toward women and behaviors such as rape result directly from exposure to sexually violent media.
Case-study method has also been used to investigate the common assertion that alcohol enhances sexual responsiveness and pleasure. In fact, evidence from some case studies suggests just the reverse, at least among chronic alcoholics. Alcoholic subjects have shown decreased arousability and lowered sexual interest, although it is possible that this effect is due to the general physical deterioration that accompanies heavy, long-term alcohol use.
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16. Non-Experimental Research Methods: Case Studies (cont’d.)
Advantages
In depth explorations
Flexibility in data gathering procedures
Disadvantages
Hard to generalize results
Often based on retrospective self-report
Not suitable for many research questions
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17. Non-Experimental Research Methods: Surveys
Asks participants about experiences or attitudes
Small to large samples
Data gathered using:
Face-to-face interviews
Questionnaires
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18. Non-Experimental Research Methods: Surveys (cont’d.)
Choosing the sample
Representative sample: limited sample that provides an accurate representation of the larger target population
Random sample: randomly chosen subset of a population
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19. Non-Experimental Research Methods: Surveys (cont’d.)
Advantages
Questionnaires: quick and cheap; anonymity may improve honesty
Interviews: more flexible; rapport may be established; possibly improved understanding
Disadvantages
Non-response
Inaccurate information
Demographic bias
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20. Non-Experimental Research Methods: Surveys (cont’d.)
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21. Non-Experimental Research Methods: Direct Observation
Observe and record responses of subjects
Small to moderate samples
Advantages
Eliminates possibility of falsification
Records can be kept indefinitely
Disadvantage
Behavior is influenced by observation
Classroom Discussion Topic: What are the advantages and disadvantages of each of the three nonexperimental research methods used to study sexuality?
Classroom Discussion Topic: Which of the nonexperimental research
methods has provided the most data about human sexuality?
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22. Observation Question
Let’s say you are observing aggressive behavior on playgrounds and you see a group of boys beating up another boy. What should you do?
You observe that classmates who get good grades tend to sit toward the front of the classroom, while those who receive poor grades tend to sit toward the back. What are three possible cause-and-effect relationships for this nonexperimental observation?
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23. The Experimental Method
Conducted in a controlled laboratory
Subjects’ reactions can be reliably measured
Independent variable: component manipulated
Dependent variable: resulting behavior
Advantage
Causal relationships can be identified
Disadvantage
Artificial settings
Classroom Discussion Topic: How do researchers study sexual behavior in laboratory investigations of human sexuality?
Classroom Discussion Topic: What are the advantages and limitations of experimental studies of human sexuality?
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24. Dependent and Independent Variables
The variables that are considered to be the “cause”
Usually manipulated by the researcher
Dependent Variables
The variables that are considered to be the “effect”
Usually measured by the researcher
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25. Plotting the independent and dependent variables
Independent = Cause Dependent = Effect
Dependent variable
y-axis
Independent variable
x-axis
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26. The Experimental Method
Classroom Discussion Topic: How do researchers study sexual behavior in laboratory investigations of human sexuality?
Classroom Discussion Topic: What are the advantages and limitations of experimental studies of human sexuality?
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27. NON-EXPERIMENTAL VERSUS EXPERIMENTAL METHODS
The casual possibilities in a non-experimental study
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28. Research Methods Table 2.1 A Summary of Research Methods
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29. COMPARISON OF NON-EXPERIMENTAL AND EXPERIMENTAL METHODS
DESCRIPTION
EXAMPLES
ADVANTAGES
DISADVANTAGES
NON-EXPERIMENTAL
Relationships studied by making observations or measuring variables as they exist naturally
Behavior observed as it naturally occurs Asking people to describe behavior Directly observing behavior Recording physiological responses Examining public records
Allows measure of covariation between variables IV can be observed in a natural context
Allows us to study participant variables that cannot be manipulated
Difficult to infer cause and effect Direction and third variable problem Difficult to control many aspects of the situation
EXPERIMENTAL
Direct manipulation and control of variables, then response or result is observed
Measuring behavior then introducing a manipulation and measuring an outcome Random assignment of participants, experimental group experiences manipulation, control group does not, outcome variable is measured
Reduces ambiguity in interpretation of results regarding cause and effect Attempts to eliminate the impact of all possible confounding third variables Permits greater experimental control Reduces the possible influence of extraneous variables through randomization
High control may create an artificial atmosphere Can be unethical or impractical
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30. CAUSALITY Inferences of Cause and Effect Require Three Elements:
Temporal precedence
Covariation between the two variables
Need to eliminate plausible alternative explanations
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31. NONEXPERIMENTAL VERSUS EXPERIMENTAL METHODS
Nonexperimental Method
Direction of Cause and Effect
The Third-Variable or Confounding Variable Problem
Experimental Method
Experimental Control
Randomization
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32. Randomization
The number of potential confounding variables is infinite but the experimental method attempts to deal with this problem through randomization which ensures that the extraneous confounding variable is as likely to affect one group as it is the other. Any variable that cannot be held constant can be controlled by randomization pg82
Example If experiment is conducted over several days the researcher can use a random order of scheduling the sequence of the various experimental conditions (or can use a cross over) so that one group is not consistently studied in the morning or the afternoon

33. Random assignment
The thing that makes random assignment so powerful is that greatly decreases systematic error – error that varies with the independent variable
Extraneous variables that vary with the levels of the independent variable are the most dangerous type in terms of challenging the validity of experimental results. These types of extraneous variables have a special name, confounding variables. For example, instead of randomly assigning students, the instructor may test the new strategy in the gifted classroom and test the control strategy in a regular class. Clearly, ability would most likely vary with the levels of the independent variable. In this case pre-knowledge would become a confounding extraneous variable

34. Relationships between Variables
Validity which refers to the degree to which a test or other measure assesses or measures what it claims to measure is known as construct validity Does the operational definition reflect the true meaning of the variable? Pg71
Validity which refers to whether you can generalize your results to other populations or situations is known as external validity (generalizability) pg85
Internal validity is a property of scientific studies which reflects the extent to which a causal conclusion

35. Biggest Threats to Construct Validity
Participant Reactivity to the Experimental Situation: Research participants motives and tendencies that affect their perceptions of the situation and their responses on the dependent variable.
Demand Characteristics: Any of the cues available in an experiment, such as instructions, rumors, or setting characteristics, that influence the responses of participants.
Experimenter Bias: Actions and characteristics of researchers that influence the responses of participants

36. Common Threats to Validity
History--the specific events which occur between the first and second measurement.
Maturation--the processes within subjects which act as a function of the passage of time. i.e. if the project lasts a few years, most participants may improve their performance regardless of treatment.
Testing--the effects of being measured may change the behavior or performance of the subject.
Instrumentation--the changes in the instrument, observers, or scorers which may produce changes in outcomes.

37. Threats to Internal Validity (continued)
Statistical regression-It is also known as regression to the mean. This threat is caused by the selection of subjects on the basis of extreme scores or characteristics. Give me forty worst students and I guarantee that they will show immediate improvement right after my treatment
Selection of subjects--the biases which may result in selection of comparison groups. Randomization (Random assignment) of group membership is a counter-attack against this threat

38. External Validity
External validity refers to what extent the results can be generalized aka Generalizability
Can the results of a study be replicated with other operational definitions, different subjects, different settings
Researchers most interested in internal validity, establishing a relationship between two variables, may more likely conduct the study in a lab setting with a restricted sample while a researcher more interested in external validity might conduct a nonexperimental design with a more diverse sample

39. Summary of three validities
Validity refers to an accurate representation (‘truth’) and can be evaluated by three types of validity
Construct validity-refers to the adequacy of the operational definition of the variables studied
Internal validity-refers to our ability to draw accurate conclusions about causal relationships
External validity-refers to the extent to which results of a study can be generalized to other populations and settings

40. Example of Construct Validity
For example, a researcher tests an intensive counseling program as a way of helping smokers give up cigarettes. At the end of the study, the results show that 64% of the subjects successfully gave up.
Sadly, the researcher then finds that some of the subjects also used nicotine patches and gum, or electronic cigarettes. The construct validity is now too low for the results to have any meaning. Only good planning and monitoring of the subjects can prevent this
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41. Bobo Doll Experiment
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42. Bobo Doll Validity
Construct Validity: Is copying the adult figure a measure of aggression? Seemed like they were playfully hitting and not aggressive?
External Validity: The bobo doll study has low external validity because it only observed children from 37 to 69 months of age, and therefore the findings of this study can only be generalized to children within this age range and can not tell us why a 10 year old would imitate behavior they observe on television.
Internal validity: Overall the study has high internal validity because instrumentation remained constant, all children played with the same toys, so a differences in toys would not have lead to a change in aggression. Similarly because this study was conducted as a independent measure design there was no maturation or testing effects from experience of the investigation.
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