Transcript Lecture Powerpoint for Ch. 2
THIRD EDITION
PSYCHOLOGY
from inquiry to understanding
CHAPTER
2 Research Methods SAFEGUARDS AGAINST ERROR
Slides prepared by Matthew Isaak
Copyright © 2014, © 2011, © 2009 by Pearson Education, Inc.
All Rights Reserved
Learning Objectives
Identify two modes of thinking and their application to scientific reasoning.
Describe the advantages and disadvantages of using naturalistic observation, case studies, self-report measures, and surveys.
Describe the role of correlational designs and distinguish correlation from causation.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Learning Objectives
Identify the components of an experiment, the potential pitfalls that can lead to faulty conclusions, and how psychologists control for these pitfalls.
Explain the ethical obligations of researchers toward their research participants.
Describe both sides of the debate on the use of animals as research subjects.
Identify uses of various measures of central tendency and variability.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Learning Objectives
Explain how inferential statistics can help us to determine whether we can generalize from our sample to the full population.
Show how statistics can be misused for purposes of persuasion.
Identify flaws in research designs and how to correct them.
Identify skills for evaluating psychological claims in the popular media.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Lecture Preview
• • • • • The beauty and necessity of good research design The scientific method Ethical issues in research design Statistics Evaluating psychological research Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Why We Need Research Designs
LO 2.1 Identify two modes of thinking and their application to scientific reasoning.
• • • In the early 1990s, an autism treatment was developed called "facilitated communication." The developers thought that autism was a motor disorder.
The facilitator sat next to child with autism and guided the child's hand over a keyboard, allowing the children to type out words.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Why We Need Research Designs
LO 2.1 Identify two modes of thinking and their application to scientific reasoning.
• • • Students seemed to make stunning progress in communication, telling parents "I love you" and writing poetry.
However, some students began making allegations of sexual abuse against parents.
There was no physical evidence, just the communicators via the facilitators.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Why We Need Research Designs
LO 2.1 Identify two modes of thinking and their application to scientific reasoning.
• • Dozens of controlled studies examined the phenomenon and found that the words came solely from the minds of the facilitators.
Still, some people continue to practice facilitated communication.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Figure 2.1 Putting Facilitated Communication to the Test.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Why We Need Research Designs
LO 2.1 Identify two modes of thinking and their application to scientific reasoning.
• • Even well-educated, intelligent people can be fooled.
Well-planned designs can help to eliminate biases when examining phenomena.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Why We Need Research Designs
LO 2.1 Identify two modes of thinking and their application to scientific reasoning.
• • • • Prefrontal lobotomy is example of what happens when we rely on subjective impressions.
Developer won the Nobel Prize In it, the neural fibers connecting frontal lobes to the thalamus were severed.
Control studies showed it didn't work.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Figure 2.2 The Prefrontal Lobotomy.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Two Modes of Thinking
LO 2.1 Identify two modes of thinking and their application to scientific reasoning.
System I or intuitive thinking • Quick, reflexive, almost automatic • Relies on heuristics System 2 or analytical thinking • Slow, reflexive, effortful Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Two Modes of Thinking
LO 2.1 Identify two modes of thinking and their application to scientific reasoning.
• • Heuristics are mental shortcuts or rules of thumb that we use daily.
– They reduce the cognitive energy required to solve problems but we oversimplify reality.
Imagine yourself driving from Reno, Nevada to San Diego, California—which compass direction would you take?
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
San Diego is actually EAST of Reno
LO 2.1 Identify two modes of thinking and their application to scientific reasoning.
FIGURE 2.3 In Which Compass Direction Would You Travel to Get from Reno, NV to San Diego, CA?
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
So, how do we prevent ourselves from being fooled by our own (and other people's) biases?
LO 2.1 Identify two modes of thinking and their application to scientific reasoning.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
The Scientific Method Toolbox
LO 2.2 Describe the advantages and disadvantages of using naturalistic observation, case studies, self-report measures, and surveys.
• • • Allows us to test specific hypotheses derived from broader theories of how things work.
Theories are never "proven," but hypotheses can be confirmed or disconfirmed.
We can use a number of different types of SM tools to gain information and test hypotheses.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Naturalistic Observation
LO 2.2 Describe the advantages and disadvantages of using naturalistic observation, case studies, self-report measures, and surveys.
• • • Watching behavior in real-world settings High degree of external validity extent to which we can generalize our findings to the real world Low degree of internal validity extent to which we can draw cause and-effect inferences Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Case Study Designs
LO 2.2 Describe the advantages and disadvantages of using naturalistic observation, case studies, self-report measures, and surveys.
• • • Studying one person or a small number of people for an extended period of time Common with rare types of brain damage or mental illness Helpful in providing existence proofs, but can be misleading and anecdotal Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Self Report Measures and Surveys
L O 2.2 Describe the advantages and disadvantages of using naturalistic observation, case studies, self-report measures, and surveys.
• • Psychologists often need to ask people about themselves or others.
– Self-report measures or questionnaires asses characteristics such as personality or mental illness.
– Surveys ask about a person's opinions or abilities.
Not all measures and surveys are equal.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Random Selection
LO 2.2 Describe the advantages and disadvantages of using naturalistic observation, case studies, self-report measures, and surveys.
• • The key to generalizability in surveys and questionnaire studies – Ensures every person in a population has an equal chance of being chosen to participate Non-random selection can skew results and make them inaccurate when applied to the population as a whole.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Evaluating Measures
LO 2.2 Describe the advantages and disadvantages of using naturalistic observation, case studies, self-report measures, and surveys.
• • To trust results, the measures must have: – Reliability—consistency of measurement – Validity—extent to which a measure assesses what it claims to measure A test must be reliable to be valid, but a reliable test can still be completely invalid.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Self-Report Measures
LO 2.2 Describe the advantages and disadvantages of using naturalistic observation, case studies, self-report measures, and surveys.
•
Pros
– Easy to administer – Direct (self) assessment of person's state Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Self-Report Measures
LO 2.2 Describe the advantages and disadvantages of using naturalistic observation, case studies, self-report measures, and surveys.
•
Cons
– Accuracy is skewed for certain groups (narcissists) – Potential for dishonesty – Response sets - tendencies of research subjects to distort their responses – Positive impression management – Malingering Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Rating Data
LO 2.2 Describe the advantages and disadvantages of using naturalistic observation, case studies, self-report measures, and surveys.
• • • People can also be asked to rate others on different characteristics.
This can do away with some biases in self-report, but still has problems.
Halo effect—tendency of ratings of one positive characteristic to spill over to influence the ratings of other characteristics Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Correlational Designs
LO 2.3 Describe the role of correlational designs and distinguish correlation from causation.
• • • Examine how two variables are related Correlations vary from -1 to +1 and can be: – Positive (as one increases, so does the other) – Negative (as one increases, the other decreases) – Zero (no relationship between variables) Depicted in a scatterplot Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Scatterplots
LO 2.3 Describe the role of correlational designs and distinguish correlation from causation.
Figure 2.4 Diagram of Three Scatterplots.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Correlational Designs
LO 2.3 Describe the role of correlational designs and distinguish correlation from causation.
• • Illusory Correlation—perception of a statistical association where none exists – Crime rates and the full moon – Arthritis and weather Examining a probability table helps to explain why we are all prone to seeing relationships where none exists.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
The Great Fourfold Table of Life
L O 2.3 Describe the role of correlational designs and distinguish correlation from causation.
Yes Yes Did a crime occur?
No
A) Full moon + crime B) Full moon + no crime
No
C) No full moon + crime D) No full moon + no crime Humans tend to overemphasize cell A and ignore the non-events.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Correlation vs. Causation
LO 2.3 Describe the role of correlational designs and distinguish correlation from causation.
• • Just because two things are related, does not mean that one causes another.
There are three possible explanations: – A causes B – B causes A – C causes both A and B Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Determining Causation
LO 2.4 Identify the components of an experiment, the potential pitfalls that can lead to faulty conclusions, and how psychologists control for these pitfalls.
• • The only way to determine if one thing is casually related to another is via an experimental design.
This is because in an experiment, you purposefully manipulate variables, rather than just measure already existing differences.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
What Makes a Study an Experiment?
LO 2.4 Identify the components of an experiment, the potential pitfalls that can lead to faulty conclusions, and how psychologists control for these pitfalls.
• Random assignment of participants groups – Experimental Group - receives the manipulation – Control Group - does not receive the manipulation Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
What Makes a Study an Experiment?
LO 2.4 Identify the components of an experiment, the potential pitfalls that can lead to faulty conclusions, and how psychologists control for these pitfalls.
• Manipulation of an independent
variable
– The dependent variable is what the experimenter measures to see whether manipulation had an effect.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
What Makes a Study an Experiment?
LO 2.4 Identify the components of an experiment, the potential pitfalls that can lead to faulty conclusions, and how psychologists control for these pitfalls.
• • Confounds - any difference between the experimental and control groups aside from IV – Makes IV effects uninterpretable Cause and effect - possible to infer, with random assignment and manipulation of independent variable Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Pitfalls in Experimental Design
LO 2.4 Identify the components of an experiment, the potential pitfalls that can lead to faulty conclusions, and how psychologists control for these pitfalls.
• • Placebo effect - improvement resulting from the mere expectation of improvement – Participants must be blind to their assignment to groups.
– Placebos show many of the same characteristics as real drugs.
Nocebo effect - harm resulting from the mere expectation of harm Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Pitfalls of Experimental Design
LO 2.4 Identify the components of an experiment, the potential pitfalls that can lead to faulty conclusions, and how psychologists control for these pitfalls.
• • Experimenter expectancy effect – when researchers' hypotheses lead them to unintentionally bias a study outcome – Clever Hans, the mathematical horse – Rosenthal's undergrads and maze-bright or maze-dull rats Using a double-blind design can decrease this.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Pitfalls of Experimental Design
LO 2.4 Identify the components of an experiment, the potential pitfalls that can lead to faulty conclusions, and how psychologists control for these pitfalls.
• • Demand characteristics - cues that participants pick up allowing them to guess at the researcher's hypotheses Disguising the purpose of the study or using "filler" items can help to decrease these.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Ethical Issues in Research Design
LO 2.5 Explain the ethical obligations of researchers toward their research participants.
• Tuskegee study ran from 1932 to 1972 – African American men living in rural Alabama diagnosed with syphilis – U.S. Public Health Service never informed, or treated, the men; they merely studied the course of the disease.
– 28 men died of syphilis, 100 of related complications, 40 wives were infected, and 19 children were born with it.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Ethical Guidelines for Human Research
LO 2.5 Explain the ethical obligations of researchers toward their research participants.
• • Today, research has to go through a careful process of review to ensure that it is conducted ethically.
Institutional Review Board (IRB)
–
Informed consent
– Justification of deception – Debriefing of subjects afterwards Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Ethical Issues in Animal Research
LO 2.6 Describe both sides of the debate on the use of animals as research subjects.
• • • Only 7-8% of psychological research uses animals.
Vast majority are rodents and birds Goal is to generate ideas about the brain and behavior without harming people Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Statistics: The Language of Research
LO 2.7 Identify uses of various measures of central tendency and variability.
• • Descriptive statistics—numerical characterizations of the data set Central tendency—where the group tends to cluster – Mean: average of all scores – Median: middle score in the data set – Mode: most frequent score in the data set Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Figure 2.7 Distribution Curves.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Statistics: The Language of Research
LO 2.7 Identify uses of various measures of central tendency and variability.
• • • Variability—sense of how loosely or tightly bunched scores are Range—difference between the highest and lowest scores Standard deviation—measure that takes into account how far each data point is from the mean Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Range vs. Standard Deviation
LO 2.7 Identify uses of various measures of central tendency and variability. • • Both sets of data have the same range, but very different standard deviations.
Standard deviations are less susceptible to extreme scores than ranges are.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
FIGURE 2.8 The Range versus the Standard Deviation.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Statistics: The Language of Research
LO 2.8 Explain how inferential statistics can help us to determine whether we can generalize from our sample to the full population.
• Inferential statistics allow us to determine whether we can generalize findings from our sample to the population.
– Statistical significance - finding would have occurred by chance less than 1 in 20 times – Practical significance - real-world importance Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
How People Lie With Statistics
LO 2.9 Show how statistics can be misused for purposes of persuasion.
• People can misuse statistics to persuade – and mislead – others. They can: – Report unrepresentative measures, like the mean instead of the median for skewed data – Truncate the axes of graphs – Neglect base rate probabilities Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Figure 2.9 Arrest Rates Before and After Transcendental Meditation.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Evaluating Psychological Research
LO 2.10 Identify flaws in research designs and how to correct them.
• • The process of peer review helps to identify and correct flaws in research and research conclusions.
Remember to keep a look out for confounds, placebos, experimenter expectancy, correlation vs. causation, and others.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf
Evaluating Psychology in the Media
LO 2.11 Identify skills for evaluating psychological claims in the popular media.
• • Most reporters are not scientists, so consider the source.
– Tabloids vs. science magazines Beware of sharpening, leveling, and pseudosymmetry.
Understanding Psychology: from Inquiry to Understanding, Third Edition Lilienfeld | Lynn | Namy | Woolf