1. 2
How Psychologists
Do Research

2. Precision LO2.1 Describe five characteristics of an ideal scientist.
Sometimes investigating simply because of a hunch about some behavior.
Often start out with a general theory that purports to explain certain phenomena and how they are related.

3. Skepticism LO2.1 Describe five characteristics of an ideal scientist.
Scientists do not accept ideas on faith or authority
Some of the greatest scientific advances have been made by those who doubt what everyone else assumed to be true
In the world of science, skepticism means treating conclusions, both new and old, with caution.

4. Reliance on empirical evidence LO2
Reliance on empirical evidence LO2.1 Describe five characteristics of an ideal scientist.
Reliance on empirical evidence
Scientific theories and hypotheses are not judged by how entertaining they are or whether they fit our prejudices and preferences.
An idea may initially generate excitement because it is plausible or imaginative, but it must eventually be backed by empirical evidence.

5. Willingness LO2.1 Describe five characteristics of an ideal scientist.
Willingness to make “risky predictions”
Principle of falsifiability: Related principle that a scientist must state an idea in a way that it can be refuted, or disproved by counterevidence.
Does not mean that the idea will be disproved, only that it could be if contrary evidence were to be discovered.
A scientist must risk disconfirmation by predicting what will happen and what will not happen.

6. The Principle of Falsifiability LO2
The Principle of Falsifiability LO2.3 Explain why falsifiability is an important component of scientific research.

7. Openness LO2.1 Describe five characteristics of an ideal scientist.
Willingness to make “risky predictions”
Science depends on the free flow of ideas
Scientists must be willing to tell others where they got their ideas, how they tested them, and what the results were.
They must share ideas so other scientists can replicate studies and verify—or challenge—findings.

8. Theory LO2.2 Distinguish between a theory, a hypothesis, and an operational definition.
Organized system of assumptions and principles that purports to explain a specified set of phenomena and their interrelationships.

9. Hypothesis LO2.2 Distinguish between a theory, a hypothesis, and an operational definition.
Statement that attempts to predict or account for a set of phenomena; scientific hypotheses specify relationships among variables and are empirically tested.

10. Critical Thinking Guidelines
Theory
Predictions, w/ operational definitions
Hypothesis
Evidence
Hunch

11. Operational Definition LO2
Operational Definition LO2.2 Distinguish between a theory, a hypothesis, and an operational definition.
Operational definition
Precise definition of a term in a hypothesis, which specifies the operations for observing and measuring the process or phenomenon being defined

12. The Principle of Falsifiability LO2
The Principle of Falsifiability LO2.3 Explain why falsifiability is an important component of scientific research.
Importance of falsifiability
Forces scientists to “analyze assumptions and biases” in a fair-minded fashion
Until results are replicated and verified, scientists must “tolerate uncertainty”

13. Descriptive Studies LO2
Descriptive Studies LO2.4 Describe the major ways participants are selected for psychological studies, and why the method of selection might influence interpretations of a study’s outcomes.
Descriptive studies:
Establishing the facts
A representative sample is a group of individuals, selected from a population for study, which matches the population on important characteristics such as age and sex.
A convenience sample is a sample of people who happen to be available; more often than not, this means undergraduate college students.

14. Case Studies LO2.5 Discuss the advantages and disadvantages of using case studies and observational methods as a means of data collection.
Case studies
A case study (or case history) is a detailed description of a particular individual based on careful observation or formal psychological testing.
A detailed description of a particular individual being studied or treated
Most commonly used by clinicians; occasionally used by academic researchers
Advantage: produce a more detailed picture of an individual
Disadvantages: missing information, observer biases

15. Observational Studies LO2
Observational Studies LO2.5 Discuss the advantages and disadvantages of using case studies and observational methods as a means of data collection.
Observational studies
Studies in which researchers carefully and systematically observe and record behavior without interfering with the behavior
Naturalistic observation: Purpose is to observe how people or animals behave in their natural environments
Laboratory observation: Purpose is to observe how people or animals behave in a more controlled setting
Disadvantage: People may behave differently than in their usual surroundings

16. Tests LO2.6 Explain why norms, reliability, and validity are the three key hallmarks of any standardized psychological test.
Tests
Procedures used to measure and evaluate personality traits, emotional states, aptitudes, interests, abilities, and values
Psychological tests can be objective or projective
Characteristics of a good test include
Standardization
Reliability
Validity

17. Standardization LO2.6 Explain why norms, reliability, and validity are the three key hallmarks of any standardized psychological test.
The test is constructed to include uniform procedures for giving and scoring the test.
In order to score tests in a standardized way, an individual’s outcome or score is compared to norms.
To establish norms, the test is given to a large group of people who are similar to those for whom the test is intended.
By having norms or established standards of performance, we know who scores low, average, or high.

18. Reliability LO2.6 Explain why norms, reliability, and validity are the three key hallmarks of any standardized psychological test.
Reliability
When constructing a test, the consistency of scores derived from a test, from one time and place to another.

19. Reliability, cont’ LO2.6 Explain why norms, reliability, and validity are the three key hallmarks of any standardized psychological test.

20. Validity LO2.6 Explain why norms, reliability, and validity are the three key hallmarks of any standardized psychological test.
Validity
The ability of a test to measure what it was designed to measure
Content validity
The test broadly represents the trait in question
Criterion validity
The test predicts other measures of the trait in question

21. Validity, cont’ LO2.6 Explain why norms, reliability, and validity are the three key hallmarks of any standardized psychological test.

22. Surveys LO2.7 Describe the advantages and limitations of using surveys in data collection.
Questionnaires and interviews that ask people directly about experiences, attitudes, or opinions
Requires a representative sample
Group of subjects, selected from the population for study, which matches the population on important characteristics such as age and sex
Popular polls and surveys rely on volunteers

23. Surveys, cont’ LO2.7 Describe the advantages and limitations of using surveys in data collection.
Volunteer bias
A shortcoming of finding derived from a sample of volunteers instead of a representative sample; the volunteers may differ from those who did not volunteer.

24. Surveys, cont’ LO2.7 Describe the advantages and limitations of using surveys in data collection.
Internet surveys
Web-based samples are often huge, consisting of hundreds of thousands of respondents, and they are frequently more diverse than traditional samples in terms of gender, socioeconomic status, geographic region, and age.

25. Correlational Studies LO2
Correlational Studies LO2.8 Explain what positive and negative correlations signify about the relationship between two variables.
Measuring correlations
Correlational study
A descriptive study that looks for a consistent relationship between two phenomena.
Correlation
A statistical measure of the strength of the relationship between two variables.

26. Correlational Studies, cont’ LO2
Correlational Studies, cont’ LO2.8 Explain what positive and negative correlations signify about the relationship between two variables.
Variables
Characteristics of behavior or experience that can be measured or described by a numeric scale.
Variables are manipulated and assessed in scientific studies.

27. Correlational Studies, cont’ LO2
Correlational Studies, cont’ LO2.8 Explain what positive and negative correlations signify about the relationship between two variables.
Positive correlation
An association between increases in one variable and increases in another—or between decreases in one and in another.

28. Correlational Studies, cont’ LO2
Correlational Studies, cont’ LO2.8 Explain what positive and negative correlations signify about the relationship between two variables.
Negative correlation
An association between increases in one variable and decreases in another.

29. Correlational Studies, cont’ LO2
Correlational Studies, cont’ LO2.8 Explain what positive and negative correlations signify about the relationship between two variables.
Measuring correlation

30. Correlational Studies, cont’ LO2
Correlational Studies, cont’ LO2.8 Explain what positive and negative correlations signify about the relationship between two variables.
Measuring correlation

31. Correlational Studies, cont’ LO2
Correlational Studies, cont’ LO2.8 Explain what positive and negative correlations signify about the relationship between two variables.
Measuring correlation

32. Coefficient of Correlation LO2
Coefficient of Correlation LO2.9 Illustrate with an example how the coefficient of correlation gives both size and direction of the relationship between two variables.
Coefficient of correlation
A measure of correlation that ranges in value from
-1.00 to
Perfect positive correlation: +1.00
Perfect negative correlation: -1.00
When there is no association between two variables, the coefficient is zero, or close to zero.
An association between increases in one variable and increases in another—or between decreases in one and in another

33. Explaining correlations LO2
Explaining correlations LO2.10 Explain why a correlation between two variables does not establish a causal relationship between those variables.
Explaining correlations
Start with two variables (X, Y)
X might cause Y
Y might cause X
Correlation does not establish causation.

34. Experiments LO2.11 Contrast an independent variable from a dependent variable, and an experimental group from a control group, and given an example of each concept in a psychology experiment.
Experiments: Hunting for causes
An experiment is a controlled test of a hypothesis in which the researcher manipulates one variable to discover its effect on another.

35. Experiments, cont’ LO2.11 Contrast an independent variable from a dependent variable, and an experimental group from a control group, and given an example of each concept in a psychology experiment.
Do cell phone use and driving mix?

36. Experiments, cont’ LO2.11 Contrast an independent variable from a dependent variable, and an experimental group from a control group, and given an example of each concept in a psychology experiment.
Variables of interest
Independent variables are variables that an experimenter manipulates.
Dependent variables are variables that an experimenter predicts will be affected by manipulations of the independent variable.
When psychologists set up an experiment, they think, “If I do X, then my participants will do Y.”
The “X” represents the independent variable.
The “Y” represents the dependent variable.

37. Experimental & Control Conditions LO2
Experimental & Control Conditions LO2.12 Explain why random assignment, single-blind, and double-blind procedures are crucial to establishing the soundness of an experiment.
Control Condition
In an experiment, a comparison condition in which participants are not exposed to the same treatment as in the experimental condition.
In some experiments, the control group is given a placebo, an inactive substance or fake treatment.

38. Experimental & Control Conditions, cont’ LO2
Experimental & Control Conditions, cont’ LO2.12 Explain why random assignment, single-blind, and double-blind procedures are crucial to establishing the soundness of an experiment.
Random assignment
A procedure for assigning people to experimental and control groups in which each individual has the same probability as any other of being assigned to a given group.
Experimenter effects
Unintended changes in subjects’ behavior due to cues inadvertently given by the experimenter
Strategies for preventing experimenter effects include single- and double-blind studies.

39. Experimenter Effects LO2
Experimenter Effects LO2.12 Explain why random assignment, single-blind, and double-blind procedures are crucial to establishing the soundness of an experiment.
Experimenter effects
Unintended changes in subjects’ behavior due to cues inadvertently given by the experimenter
Strategies for preventing experimenter effects include single- and double-blind studies.

40. Challenges in Cross-cultural Research
Methods and sampling
Stereotyping
Reification

41. Evaluate the Findings LO2
Evaluate the Findings LO2.13 Provide an example of how the arithmetic mean and standard deviation could be used to compare the performance of two groups of research participants.
Once you have some results, you must do three things:
Describe them
Assess their reliability and meaningfulness
Figure out how to explain them

42. Evaluate the Findings LO2
Evaluate the Findings LO2.13 Provide an example of how the arithmetic mean and standard deviation could be used to compare the performance of two groups of research participants.
Descriptive statistics
Statistical procedures that organize and summarize research data.
Examples
Arithmetic mean
Standard deviation

43. Evaluate the Findings LO2
Evaluate the Findings LO2.13 Provide an example of how the arithmetic mean and standard deviation could be used to compare the performance of two groups of research participants.
Same mean, different meaning

44. Inferential Statistics LO2
Inferential Statistics LO2.14 Explain what a statistically significant research result means to an experimenter.
These are statistical procedures that allow researchers to draw inferences about how statistically meaningful a study’s results are
The most commonly used inferential statistics are significance tests.
That is, tests that show how likely it is that a study’s results occurred merely by chance.

45. Interpret the Findings LO2
Interpret the Findings LO2.15 Compare cross-sectional and longitudinal studies, and give an example of each.
Choosing the best explanation
Interpretation of results may depend on how the research was conducted.
Cross-sectional studies
People (or animals) of different ages are compared at a given time.
Longitudinal studies
People (or animals) are allowed and periodically reassessed over a period of time.

46. Interpret the Findings, cont’ LO2
Interpret the Findings, cont’ LO2.15 Compare cross-sectional and longitudinal studies, and give an example of each.
Cross-sectional studies
People (or animals) of different ages are compared at a given time.
Longitudinal studies
People (or animals) are allowed and periodically reassessed over a period of time.

47. Interpret the Findings, cont’ LO2
Interpret the Findings, cont’ LO2.15 Compare cross-sectional and longitudinal studies, and give an example of each.
Judging the results’ importance
Statistical techniques can help determine if results are really important.
Effect size is an objective, standardized way of describing the strength of the independent variable’s influence on the dependent variable.
Meta-analysis is a set of techniques for combining data from a number of related studies to determine the explanatory strength of a particular independent variable.

48. Keeping the Enterprise Ethical LO2
Keeping the Enterprise Ethical LO2.16 Discuss why the principles of informed consent and debriefing are two key characteristics of a researcher’s code of ethics.
Keeping the enterprise ethical
Informed consent
The doctrine that anyone who participates in human research must do so voluntarily and must know enough about the study to make an intelligent decision about whether to take part.
If deception is necessary, debriefing must occur

49. The Ethics of Studying Animals LO2
The Ethics of Studying Animals LO2.17 List and discuss four reasons why psychologists might use animals in research.
Animals have always been used in a small percentage of psychological studies.
To conduct basic research
To study issues that cannot be studied experimentally using human beings
To clarify theoretical questions
To improve human welfare