Methods- Chapter 1Methods- Chapter 1

I. Why is Psychology a science?I. Why is Psychology a science?

Deals with experiments and scientific Deals with experiments and scientific method.method.

A. Human TendenciesA. Human Tendencies

1. 1. Hindsight Bias:Hindsight Bias: tendency to believe, tendency to believe, after learning an outcome, that one would after learning an outcome, that one would have foreseen it.have foreseen it.

2. 2. Overconfidence:Overconfidence: to overestimate the to overestimate the accuracy of one’s beliefs and judgments.accuracy of one’s beliefs and judgments.

II. Methods of ResearchII. Methods of Research

A. A. Descriptive ResearchDescriptive Research 1. 1. Case Study:Case Study: one person is studied in one person is studied in

depth in the hope of revealing universal depth in the hope of revealing universal principles.principles.

2. 2. Survey:Survey: acquiring the self-reported acquiring the self-reported attitudes or behaviors of people, usually by attitudes or behaviors of people, usually by questioning a representative, random questioning a representative, random sample of themsample of them

3. 3. Naturalistic Observation:Naturalistic Observation: observing & observing & recording behavior in naturally occurring recording behavior in naturally occurring situations. situations. **Describes, not explains****Describes, not explains**

Methods 1-3 can only show correlations. Methods 1-3 can only show correlations. (meaning one factor predicts the other, but does (meaning one factor predicts the other, but does not necessarily cause it)not necessarily cause it)

B. Correlational ResearchB. Correlational Research 1. 1. Positive Correlations:Positive Correlations: When one variable goes When one variable goes

up the other goes up. When one variable goes up the other goes up. When one variable goes down the other variable goes down.down the other variable goes down.

2. 2. Negative Correlations:Negative Correlations: When one variable When one variable goes up the other goes down.goes up the other goes down.

3. 3. Correlation coefficient:Correlation coefficient: Statistical measure of Statistical measure of a relationship. (how well one predicts the other)a relationship. (how well one predicts the other)

4. 4. Scatter plotsScatter plots:graph showing correlation:graph showing correlation 5. 5. Correlation & CausationCorrelation & Causation:correlation :correlation

does not prove cause and effectdoes not prove cause and effect 6. 6. Illusory correlations:Illusory correlations: When we believe When we believe

there is a relationship between two things, there is a relationship between two things, we are likely to notice and recall instances we are likely to notice and recall instances that confirm our beliefthat confirm our belief

Example of Illusory CorrelationExample of Illusory Correlation

Warm-upWarm-up

Give an example, not used in class, of:Give an example, not used in class, of: 1. a positive correlation1. a positive correlation 2. a negative correlation2. a negative correlation 3. an illusory correlation3. an illusory correlation

C. C. Experimental Research-Experimental Research- Proves Cause Proves Cause and Effectand Effect

When doing an experiment you must first form When doing an experiment you must first form a a hypothesishypothesis (testable prediction). If proven (testable prediction). If proven correct over and over, the hypothesis may lead correct over and over, the hypothesis may lead to a theory (idea) to a theory (idea)

Next you must Next you must randomly select randomly select a sample from a sample from the the populationpopulation..

Second you must form an Second you must form an experimental group,experimental group, which gets the independent variable, and a which gets the independent variable, and a control group control group which does not but will get a which does not but will get a placebo in a drug studyplacebo in a drug study

The The independent variable independent variable is the factor that is the factor that you are testing.you are testing.

A A placeboplacebo is a sugar pill. is a sugar pill. You must make sure to use You must make sure to use random random

assignmentassignment when choosing who goes in when choosing who goes in the experimental and the control group.the experimental and the control group.

Single Blind Study:Single Blind Study: participant doesn’t know who participant doesn’t know who is in the experimental vs. control group.is in the experimental vs. control group.

Double Blind Study:Double Blind Study: participant and participant and experimenter don’t know who is in the experimenter don’t know who is in the experimental vs. control group.experimental vs. control group.

After the experiment you should record your After the experiment you should record your results.results.

You should always replicate your experiment.You should always replicate your experiment. Your measurable results are known as the Your measurable results are known as the

dependent variabledependent variable..

Tip:Tip: If you phrase a hypothesis as I am looking If you phrase a hypothesis as I am looking

for the effect of _________ on _______ for the effect of _________ on _______ the first blank is always the IV and the the first blank is always the IV and the second is always the DV.second is always the DV.

What are the IV and DV in the following What are the IV and DV in the following study:study:

Eating chicken makes you grow taller. Eating chicken makes you grow taller. What operational def. can you use?What operational def. can you use?

ControlsControls Controls on an experiment would includeControls on an experiment would include 1. Random selection1. Random selection 2. Random assignment2. Random assignment 3. Double-blind study3. Double-blind study 4. good 4. good operational definition operational definition of variablesof variables 5. Replication5. Replication

My Teacher is Mean!My Teacher is Mean!   Jimmy is a little upset about his grade for his Jimmy is a little upset about his grade for his

science fair project. He worked on it for an science fair project. He worked on it for an entire month. What did he do wrong?entire month. What did he do wrong?

Jimmy did a science fair project studying the Jimmy did a science fair project studying the effect of eating fish on intelligence. He began effect of eating fish on intelligence. He began his study by recruiting several of his friends to his study by recruiting several of his friends to eat at least three servings of fish sticks every eat at least three servings of fish sticks every day for one month. At the end of the month day for one month. At the end of the month Jimmy gave them all a test he printed off the Jimmy gave them all a test he printed off the internet about World War II. They scored really internet about World War II. They scored really well. Jimmy concluded that fish does indeed well. Jimmy concluded that fish does indeed increase intelligence. He even dressed up like a increase intelligence. He even dressed up like a giant fish when he gave his presentationgiant fish when he gave his presentation

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

III. StatisticsIII. Statistics

Descriptive StatisticsDescriptive Statistics 1. 1. Measures of Central Tendency:Measures of Central Tendency: a way a way

to summarize data using mean, median, to summarize data using mean, median, mode.mode.

A. A. Mean:Mean: average score. average score.

B. B. Median:Median: the middle score in a the middle score in a distribution; half the scores are above it distribution; half the scores are above it and half are below it.and half are below it.

C. C. Mode:Mode: the most frequently occurring the most frequently occurring scores in a distribution.scores in a distribution.

2. Distributions2. Distributions

A. A. Normal:Normal: when the mean, median, and when the mean, median, and mode are identical-creates symmetrical mode are identical-creates symmetrical distributiondistribution

B. B. Positively skewed:Positively skewed: when a score is when a score is much higher than the rest of the scores, much higher than the rest of the scores, making the mean higher.making the mean higher.

C. C. Negatively skewed:Negatively skewed: when a score is when a score is much lower than the rest of the scores, much lower than the rest of the scores, making the mean lower.making the mean lower.

D. D. Standard deviation:Standard deviation: determines whether determines whether information is packed together or dispersed.information is packed together or dispersed.

E. E. Variance:Variance: how similar or diverse scores are. how similar or diverse scores are. variance = standard deviation squaredvariance = standard deviation squared Example: basketball player scored between 13 & Example: basketball player scored between 13 &

17 pts in each of her first 10 games. Knowing 17 pts in each of her first 10 games. Knowing this, we would be more confident that she would this, we would be more confident that she would score near 15 points her next game than if her score near 15 points her next game than if her scores had varied form 5 to 25scores had varied form 5 to 25

3. Use of statistics in Psychology3. Use of statistics in Psychology

A. A. The Flynn effect:The Flynn effect: with every generation, with every generation, standardized test scores are getting standardized test scores are getting higher.higher.

Inferential StatisticsInferential Statistics A. A. Statistical significance:Statistical significance: how important are the how important are the

findingsfindings B. B. P Value:P Value: the likelihood that your results were the likelihood that your results were

by chanceby chance C. C. Type I error:Type I error: when your hypothesis is wrong when your hypothesis is wrong

but seems to be proven right (false-positive)but seems to be proven right (false-positive) Type II error:Type II error: when your hypothesis is right but when your hypothesis is right but

seems to be proven wrong (false-negative)seems to be proven wrong (false-negative)

IV. EthicsIV. Ethics

A. A. With humans:With humans: cannot hurt a human cannot hurt a human knowingly.knowingly.

B. B. With animals:With animals: not very many laws not very many laws protecting animals in the U.S.protecting animals in the U.S.