Thinking Critically With Psychological Science Chapter 1 AP Psychology ~ Ms. Justice

The Monty Hall Problem: Common Sense or Statistics?

BIG IDEAS The Need for Psychological Science 1: Why are the answers that flow from the scientific approach more reliable than those based on intuition and common sense? 2: What are 3 main components of the scientific attitude? How Do Psychologists Ask and Answer Questions? 3: How do theories advance psychological science? 4: How do psychologists observe and describe behavior? 5: What are positive and negative correlations, and why do they enable prediction but not cause-effect explanation? 6: What are illusory correlations? 7: How do experiments, powered by random assignment, clarify cause and effect?

BIG IDEAS Statistical Reasoning in Everyday Life 8: How can we describe data with measures of central tendency and variation? 9: What principles can guide our making generalizations from samples and deciding whether differences are significant? Frequently Asked Questions About Psychology 10: Can laboratory experiments illuminate everyday life? 11: Does behavior depend on one’s culture and gender? 12: Why do psychologists study animals, and is it ethical to experiment on animals? 13: Is it ethical to experiment on people? 14: Is psychology free of value judgments?

1: Why are the answers that flow from the scientific approach more reliable than those based on intuition and common sense?

Many people believe that intuition and common sense are enough to bring forth answers regarding human nature. Intuition and common sense may aid queries, but they are not free of error. Because of hindsight bias and judgmental overconfidence, we cannot rely solely on intuition and common sense. Preview Question 1: Why are the answers that flow from the scientific approach more reliable than those based on intuition and common sense?

the “I-knew-it-all-along” phenomenon. Hindsight Bias: the “I-knew-it-all-along” phenomenon. After learning the outcome of an event, many people believe they could have predicted that very outcome. Common sense more easily describes what has happened than what will happen.

Overconfidence: Sometimes we think we know more than we actually know. Anagrams BARGE GRABE ENTRY ETYRN WATER WREAT . How long do you think it would take to unscramble these anagrams? People said it would take about 10 seconds, yet on average they took about 3 minutes (Goranson, 1978).

2: What are 3 main components of the scientific attitude?

The scientific attitude is composed of: curiosity (passion for exploration) skepticism (doubting and questioning) and humility (ability to accept responsibility when wrong) Preview Question 2: What are the three main components of scientific attitude?

James Randi exemplifies skepticism – he has tested and debunked a variety of psychic phenomena The scientific attitude prepares us for critical thinking, which does not accept arguments and conclusions blindly... It examines assumptions, discerns hidden values, evaluates evidence and assesses conclusions. The Amazing Randi www.randi.org

James Randi Exposes Uri Geller & Peter Popoff

3: How do theories advance psychological science?

Psychologists, like all scientists, use the scientific method to construct theories that organize, summarize and simplify observations. Preview Question 3: How do theories advance psychological science?

A theory is an explanation that integrates principles and organizes and predicts behavior or events. For example, low self-esteem contributes to depression.

People with low self-esteem are apt to feel more depressed. A hypothesis is a testable prediction, often prompted by a theory, to enable us to accept, reject or revise the theory. People with low self-esteem are apt to feel more depressed.

Research Observations Research would require us to administer tests of self-esteem and depression. As a check on their biases, psychologists use precise operational definitions of procedures and concepts. This allows for replication with different participants & materials, which boosts the validity of a study.

Research Process Figure 1.1, p. 22

4: How do psychologists observe and describe behavior?

Description is the starting point of any science Among the oldest research methods is the case study: a technique in which one person (or a chimp?) is studied in depth to reveal underlying behavioral principles. Preview Question 4: How do psychologists observe and describe behavior? Is language uniquely human?

The survey, which looks at many cases in less depth, is a technique for ascertaining the self-reported attitudes, opinions or behaviors of people usually done by questioning a representative, random sample of people. http://www.lynnefeatherstone.org

Survey: Wording Effects Wording can change the results of a survey. Q: Should cigarette ads and pornography be allowed on television? (versus not allowed or forbid) People are much more likely to approve “not allowing” such things than “forbidding” or “censoring” them. “aid to the needy” vs. “welfare” “affirmative action” vs “preferential treatment” “revenue enhancers” vs. “taxes”

Survey: Random Sampling If each member of a population has an equal chance of inclusion into a sample, it is called a random sample (unbiased). If the survey sample is biased, its results are not valid. The fastest way to know about the marble color ratio is to blindly transfer a few into a smaller jar and count them.

Naturalistic Observation Observing and recording the behavior of animals in the wild, or recording self-seating patterns in a multiracial school lunch room are examples of naturalistic observation. Courtesy of Gilda Morelli Before we move on…. Remember that these descriptive methods do not explain behavior.

5: What are positive and negative correlations, and why do they enable prediction but not cause-effect explanation?

(positive or negative) Correlation When one trait or behavior accompanies another, we say the two correlate. Indicates strength of relationship (0.00 to 1.00) Correlation coefficient r = + 0.37 Preview Question 5: What are positive and negative correlations, and why do they enable prediction but not cause-effect explanation? Indicates direction of relationship (positive or negative) Correlation coefficient is a statistical measure of the relationship between two variables.

Scatterplots A scatterplot is a graph comprised of points that are generated by values of two variables. The slope of the points depicts the direction, while the amount of scatter depicts the strength of the relationship.

Scatterplots Perfect negative correlation (-1.00) Perfect positive If 2 sets of scores relate inversely (one set going up as the other goes down), the correlation is negative. (Example: toothbrushing & decay) Perfect positive correlation (+1.00) If 2 sets of scores tend to rise or fall together, the correlation is positive. (Example: height & weight) No relationship (0.00) A weak correlation, indicating little relationship, has a coefficient near zero. Note: Perfect correlations rarely occur in the “real world”

Data Data showing height and temperament in people: Is there a positive correlation, negative correlation, or little-to-no correlation? Table 1.2, p. 26

Scatterplot The Scatterplot below shows the relationship between height and temperament in people. Table 1.3, p. 27

Correlation and Causation Correlation does not mean causation! or Table 1.4, p. 27

6: What are illusory correlations?

Illusory Correlation: A perceived, but nonexistent, correlation. Illusory correlations can help explain many superstitious beliefs, such as the presumption that infertile couple who adopt become more likely to conceive. Confirming evidence Disconfirming evidence Do not adopt Adopt Do not conceive Conceive Preview Question 6: What are illusory correlations? Michael Newman Jr./ Photo Edit Figure 1.5, p. 29

Given random data, we look for order and meaningful patterns. Order in Random Events Given random data, we look for order and meaningful patterns. Your chances of being dealt either of these hands is precisely the same: 1 in 2,598,960.

Order in Random Events “With a large enough sample, any outrageous thing is likely to happen.” ~Diaconis and Mosteller An event that happens to but one in 1 billion people every day occurs about 6 times a day – 2000 times a year. Jerry Telfer/ San Francisco Chronicle Angelo and Maria Gallina won two California lottery games on the same day.

7: How do experiments, powered by random assignment, clarify cause and effect?

Exploring Cause and Effect Experimentation: Exploring Cause and Effect Like other sciences, experimentation is the backbone of psychological research. Experiments isolate causes and their effects. Preview Question 7: How do experiments, powered by random assignment, clarify cause and effect?

Exploring Cause & Effect Many factors influence our behavior. Experiments (1) manipulate factors of interest, while other factors are kept under (2) control. Effects generated by manipulated factors isolate cause and effect relationships. For example: the effects of bottle feeding vs. breast-feeding on intelligence vs.

Double-blind Procedure Evaluating Therapies Double-blind Procedure In evaluating drug therapies, patients and experimenter’s assistants should remain unaware of which patients had the real treatment and which patients had the placebo treatment.

Evaluating Therapies Random Assignment Assigning participants to experimental (drug therapy) and control (placebo) conditions by random assignment minimizes pre-existing differences between the two groups. NOT random assignment!

Independent Variable An independent variable is a factor manipulated by the experimenter. The effect of the independent variable is the focus of the study. For example, when examining the effects of breast feeding upon intelligence, breast feeding is the independent variable.

Dependent Variable A dependent variable is a factor that may change in response to an independent variable. In psychology, it is usually a behavior or a mental process. For example, in our study on the effect of breast feeding upon intelligence, intelligence is the dependent variable.

Look for the DV first when identifying variables in a study Look for the DV first when identifying variables in a study. Ask yourself, “What is the researcher measuring or looking for in this study?” Look for the IV second when identifying variables in a study. Ask yourself, “What do the researchers hope will cause the DV in this study?” Find the IV & the DV Hypothesis from a 2002 study: "There will be a statistically significant difference in graduation rates of at-risk high-school seniors who participate in an intensive study program as opposed to at-risk high-school seniors who do not participate in the intensive study program."

Experimentation A summary of steps during experimentation (effects of bottle feeding vs. breast-feeding on intelligence.) Figure 1.7, p. 32

Below is a comparison of different research methods. Table 1.3, p. 33

8: How can we describe data with measures of central tendency and variation?

Statistical Reasoning Statistical procedures analyze and interpret data allowing us to see what the unaided eye misses. Composition of ethnicity in urban locales

Statistical Reasoning in Everyday Life Doubt big, round, undocumented numbers as they can be misleading and before long, become public misinformation. Apply simple statistical reasoning in everyday life to think smarter!

Describing Data A meaningful description of data is important in research. Misrepresentation may lead to incorrect conclusions. Preview Question 8: How can we describe data with measures of central tendency and variation?

Measures of Central Tendency Mode: The most frequently occurring score in a distribution. Mean: The arithmetic average of scores in a distribution obtained by adding the scores and then dividing by the number of scores that were added together. Median: The middle score in a rank-ordered distribution.

Measures of Central Tendency A Skewed Distribution

Measures of Variation Range: The difference between the highest and lowest scores in a distribution. Standard Deviation: A computed measure of how much scores vary around the mean.

Standard Deviation Table 1.4, p. 36

Normal Curve A symmetrical, bell-shaped curve that describes the distribution of many types of data (normal distribution). Most scores fall near the mean.

9: What principles can guide our making generalizations from samples and deciding whether differences are significant?

When is an Observed Difference Reliable? In deciding when it is safe to generalize from a sample, keep 3 principles in mind: Representative samples are better than biased samples. Less-variable observations are more reliable than more variable ones. More cases are better than fewer cases. Preview Question 9: What principles can guide our making generalizations from samples and deciding whether differences are significant?

When is a Difference Significant? When sample averages are reliable and the difference between them is relatively large, we say the difference has statistical significance. It is probably not due to chance variation. For psychologists this difference is measured through alpha level set at 5 percent.

Frequently Asked Questions About Psychology 10. Can laboratory experiments illuminate everyday life? Answer: Artificial laboratory conditions are created to study behavior in simplistic terms. The goal is to find underlying principles that govern behavior. Those principles, not the specific findings, help explain everyday behaviors. Preview Question 10: Can laboratory experiments illuminate everyday life?

11. Does behavior depend on one’s culture and gender? Answer: Even when specific attitudes and behaviors vary across cultures, as they often do, the underlying processes are much the same. Biology determines our sex, and culture further bends the genders. However, in many ways woman and man are similarly human. Our shared biological heritage unites us. Preview Question 11: Does behavior depend on one’s culture and gender? Ami Vitale/ Getty Images

12. Why do psychologists study animals, and is it ethical to experiment on animals? Studying animals gives us the understanding of many behaviors that may have common biology across animals and humans. From animal studies, we have gained insights to devastating and fatal diseases. All researchers who deal with animal research are required to follow ethical guidelines in caring for these animals. Preview Question 12: Why do psychologists study animals, and is it ethical to experiment on animals? D. Shapiro, © Wildlife Conservation Society

13. Is it ethical to experiment on people? Answer: Yes. Experiments that do not involve any kind of physical or psychological harm beyond normal levels encountered in daily life may be carried out. Ethical principles urge researchers to: Obtain informed consent Protect from harm and discomfort Maintain confidentiality Explain research afterward Preview Question 13: Is it ethical to experiment on people?

Ethics in Psychological Research: The Stanford Prison Experiment

14. Is psychology free of value judgments? Answer: No. Psychology emerges from people who subscribe to a set of values and judgments that determine what will be studied, how it will be studied, and how the results will be interpreted. Preview Question 14: Is psychology free of value judgments? © Roger Shepard