Methods- Chapter 1

I. Why is Psychology a science?  Deals with experiments and scientific method.

A. Human Tendencies  1. Hindsight Bias: tendency to believe, after learning an outcome, that one would have foreseen it.  2. Overconfidence: to overestimate the accuracy of one’s beliefs and judgments.

II. Methods of Research  A. Descriptive Research  1. Case Study: one person is studied in depth in the hope of revealing universal principles.  2. Survey: acquiring the self-reported attitudes or behaviors of people, usually by questioning a representative, random sample of them

 3. Naturalistic Observation: observing & recording behavior in naturally occurring situations. **Describes, not explains**  Methods 1-3 can only show correlations. (meaning one factor predicts the other, but does not necessarily cause it)

 B. Correlational Research  1. Positive Correlations: When one variable goes up the other goes up. When one variable goes down the other variable goes down.  2. Negative Correlations: When one variable goes up the other goes down.  3. Correlation coefficient: Statistical measure of a relationship. (how well one predicts the other)

 4. Scatter plots:graph showing correlation  5. Correlation & Causation:correlation does not prove cause and effect  6. Illusory correlations: When we believe there is a relationship between two things, we are likely to notice and recall instances that confirm our belief

Example of Illusory Correlation

Warm-up  Give an example, not used in class, of:  1. a positive correlation  2. a negative correlation  3. an illusory correlation

 C. Experimental Research- Proves Cause and Effect

 When doing an experiment you must first form a hypothesis (testable prediction). If proven correct over and over, the hypothesis may lead to a theory (idea)  Next you must randomly select a sample from the population.  Second you must form an experimental group, which gets the independent variable, and a control group which does not but will get a placebo in a drug study

 The independent variable is the factor that you are testing.  A placebo is a sugar pill.  You must make sure to use random assignment when choosing who goes in the experimental and the control group.

 Single Blind Study: participant doesn’t know who is in the experimental vs. control group.  Double Blind Study: participant and experimenter don’t know who is in the experimental vs. control group.  After the experiment you should record your results.  You should always replicate your experiment.  Your measurable results are known as the dependent variable.

 Tip:  If you phrase a hypothesis as I am looking for the effect of _________ on _______ the first blank is always the IV and the second is always the DV.  What are the IV and DV in the following study:  Eating chicken makes you grow taller. What operational def. can you use?

 Controls  Controls on an experiment would include  1. Random selection  2. Random assignment  3. Double-blind study  4. good operational definition of variables  5. Replication

My Teacher is Mean!  Jimmy is a little upset about his grade for his science fair project. He worked on it for an entire month. What did he do wrong?  Jimmy did a science fair project studying the effect of eating fish on intelligence. He began his study by recruiting several of his friends to eat at least three servings of fish sticks every day for one month. At the end of the month Jimmy gave them all a test he printed off the internet about World War II. They scored really well. Jimmy concluded that fish does indeed increase intelligence. He even dressed up like a giant fish when he gave his presentation

 There are lies, damn lies, and then there are statistics.

III. Statistics  Descriptive Statistics  1. Measures of Central Tendency: a way to summarize data using mean, median, mode.  A. Mean: average score.

 B. Median: the middle score in a distribution; half the scores are above it and half are below it.  C. Mode: the most frequently occurring scores in a distribution.

2. Distributions  A. Normal: when the mean, median, and mode are identical-creates symmetrical distribution  B. Positively skewed: when a score is much higher than the rest of the scores, making the mean higher.  C. Negatively skewed: when a score is much lower than the rest of the scores, making the mean lower.

 D. Standard deviation: determines whether information is packed together or dispersed.  E. Variance: how similar or diverse scores are.  variance = standard deviation squared  Example: basketball player scored between 13 & 17 pts in each of her first 10 games. Knowing this, we would be more confident that she would score near 15 points her next game than if her scores had varied form 5 to 25

3. Use of statistics in Psychology  A. The Flynn effect: with every generation, standardized test scores are getting higher.

 Inferential Statistics  A. Statistical significance: how important are the findings  B. P Value: the likelihood that your results were by chance  C. Type I error: when your hypothesis is wrong but seems to be proven right (false-positive)  Type II error: when your hypothesis is right but seems to be proven wrong (false-negative)

IV. Ethics  A. With humans: cannot hurt a human knowingly.  B. With animals: not very many laws protecting animals in the U.S.