Unit 2: Research Methods: Thinking Critically with Psychological Science

I. The Need For Psychological Science Unit 2: Research Methods

A. Hindsight Bias Tendency to believe, after learning an outcome, that one would have foreseen it. “I knew it all along” “Hindsight is 20/20”

B. Overconfidence Think we know more than we do! Together with hindsight bias, can lead to overestimate our intuition

Scbunrelam WREAT ETRYN GRABE

UnSrAmBlE Water Entry Barge

Common Sense

C. The Scientific Attitude Three main components Curious eagerness Skeptically scrutinize competing ideas Open-minded humility before nature

D. Critical Thinking Critical Thinking: Thinking that does not blindly accept arguments & conclusions. “Smart thinking” Four elements: Examines assumptions Discerns hidden values Evaluates evidence Assesses conclusions

II. How Do Psychologists ask/Answer Questoins? Unit 2: Research Methods II. How Do Psychologists ask/Answer Questoins?

A. The Scientific Method Scientific theory = Observations Scientific theory = explains through an integrated set of principles that organizes observations and predicts behaviors or events.

A. The Scientific Method A good theory is useful if it: Effectively organizes a range of self-reports and observations Implies clear predictions that anyone can use to check the theory (hypothesis) Operational Definitions: precise measures in reporting findings

A. The Scientific Method Evaluates competing ideas with careful observations & rigorous analysis to describe and explain human nature. 1) Identify a Problem 2) State Observations about the problem 3) Form a Hypothesis about the problem, proposed solution. (if…then…) 4) Design an Experiment to test the hypothesis- control vs. experimental 5) Collect Data 6) Form a Conclusion 7) Replicate- operational definition

B. Description Case Study Observation technique in which one person is studied in depth in the hope of revealing universal principles. Very open to bias… Why?

Survey Method Relies on self-reports: questionnaires, interviews, and surveys. Efficient and inexpensive

B. Description Naturalistic Observation Observing & recording behavior in naturally occurring situations without trying to manipulate and control the situation. Unaware they are being watched

C. Experimentation Investigator manipulates one of more factors to observe effect of some behavior. Only research that identifies cause/effect relationships

Population Random Sample The total group being studied from which a sample is drawn. Random Sample Represents a population fairly: Equal chance of being included. If it is not random it is said to be biased. Stratified Sample- ensuring that the sample represents the population in some way

Why Not Use the entire school in experiment? On the AP Exam---many times you are asked to develop an experiment/research. If so, specify the size of your sample and do not use huge sizes. Also address your ability to make it random!

Independent Variable vs. Causes something to happen Manipulated by the experimenter Should change the dependent variable Effected by independent variable Outcome of experiment Variable being measured

Control Group Not exposed to the independent variable Results are compared to those of the experimental group

Blind procedure Participants are ignorant (blind) to the expected outcome of the experiment Double blind procedure- researcher nor participants affect the outcome This eliminates subject/experimenter bias

Placebo Non-active substance or condition instead of a drug or active agent Given to the control group

Placebo Effect Video Time… http://player.discoveryeducation.com/index.cfm?guidAssetId=5F290E71-AB90-4842-A4D7-FB0DB55A682C&blnFromSearch=1&productcode=US

Longitudinal Study Study same group of individuals many years Very expensive and difficult to conduct

Longitudinal/Cross Sectional Study

Cross-Sectional Study Simultaneously study subjects from different age groups Cheaper, easier Differences may be due to factors other than development

D. Correlation Correlational Study Determines the degree to which two variables are related to one another… Illusory Correlation: belief that two things are related when indeed they aren’t. Correlation Coefficient: a statistical index of the relationship between two things (from -1 to +1).

Positive Correlation Value of 1 variable increases (or decreases) so does the value of the other variable.

Negative Correlation Value of 1 variable increases, the value of the other variable decreases.

Zero Correlation There is no relationship whatsoever between the two variables.

Homework Assignment Find an experiment or correlational study that has been conducted in last five years and bring in a copy of the article and a summary to share with the class. DUE FRIDAY!!

III. Statistical Reasoning in Everyday Life

A. Describing Data 3 Measures of Central Tendency Central Tendency = a single score that represents a whole set of scores.

Measures of Central Tendency Mean = the average of a distribution, obtained by adding the scores and then dividing by the # of scores.

Measures of Central Tendency Median = the middle score in a distribution, half the scores are above it and half are below it.

Measures of Central Tendency Mode = the most frequently occurring score(s) in a distribution

Measures of Variability Range = the difference between the highest and lowest score in a distribution. Standard Deviation= a computed measure of how much scores vary around the mean score.

Measures of Variability Normal Curve (bell shaped) = a symmetrical, bell-shaped curve that describes the distribution of many types of data; most scored fall near the mean (68 percent fall within one standard deviation of it) and fewer and fewer near the extremes.

Making Inferences When Is an Observed Difference Reliable? Representative samples are better than biased samples Less-variable observations are more reliable than those that are more variable More cases are better than fewer

B. Making Inferences When Is a Difference Significant? Statistical significance The averages are reliable The differences between averages is relatively large Does imply the importance of the results

IV. Ethics: Human Research (4 Basic Principles) Module 2: Research Strategies IV. Ethics: Human Research (4 Basic Principles)

2. Right to be Protected from Harm/Discomfort 1. Informed Consent General nature of the research Any potential risks Refuse participation or withdraw 2. Right to be Protected from Harm/Discomfort Conducted under certain circumstances Only with the informed consent

3. Right of Confidentiality Individual data about participants should never be discussed or released. 4. Right to Debriefing Receive complete explanation of research at end of the study. Important if research involves deception.

The End