2.3-2.4

• Correlation


  A relationship between two or more variables, but this relationship does not necessarily imply cause and effect
• Correlation coefficient


  A number from -1 to +1 that indicates the strength and direction of the relationship between variables
• Positive correlation


  Variables move in the same direction
• Negative correlation


  Variables move in opposite directions
• Correlation does not indicate causation
• Confounding variable


  A variable that is actually causing the systematic movement in the variables of interest
• Correlational research is limited because it cannot establish cause and effect
• Illusory correlation


  False correlations where people believe relationships exist between two things when no such relationship exists
• Confirmation bias is looking for evidence to support a hunch and ignoring evidence that would tell us the hunch is false
• Illusory correlations can lead to prejudicial attitudes and discriminatory behaviour
• Experiments are needed to establish cause and effect relationships between variables
• Illusory correlations are beliefs about relationships between variables that do not actually exist
• Confirmation bias is the tendency to look for and interpret information in a way that confirms our existing beliefs
• Illusory correlations can lead to prejudicial attitudes and discriminatory behavior
• Experiment (in scientific context)

  A study with precise requirements for design and implementation, not just trying something new
• Hypothesis


  A specific prediction about the relationship between variables that can be tested
• Conducting an experiment


  1. Formulate hypothesis

  2. Design experiment with experimental and control groups

  3. Operationalize variables

  4. Implement experiment

  5. Analyze results
• Experimental group


  The group that receives the experimental manipulation
• Control group


  The group that does not receive the experimental manipulation
• Operational definition


  A precise description of how variables are measured
• Experimenter bias


  The possibility that a researcher's expectations might skew the results of the study
• Single-blind study


  Participants are unaware of which group they are in, but researchers know
• Double-blind study


  Neither participants nor researchers know which group individuals are in
• Placebo effect


  When people's expectations or beliefs influence their experience in a given situation
• Independent variable


  The variable manipulated or controlled by the experimenter
• Dependent variable


  The variable measured to see the effect of the independent variable
• Participants


  The subjects of psychological research
• Random sample


  A subset of a larger population where every member has an equal chance of being selected
• Random assignment


  Participants are randomly assigned to experimental or control groups
• Quasi-experimental research cannot make cause-and-effect claims because the independent variable cannot be directly manipulated
• Ethical constraints limit the types of experiments researchers can conduct
• Statistical analysis


  Determines how likely any differences between groups are due to chance
• Researchers cannot directly control a person's sex when looking for differences between males and females on a task that taps into spatial memory
• Quasi-experimental research


  Research approach where the researcher cannot directly control the independent variable
• In quasi-experimental research, researchers cannot make cause-and-effect claims
• Researchers are limited by ethical constraints, such as not being able to conduct an experiment designed to determine if experiencing abuse as a child leads to lower levels of self-esteem among adults
• Statistical analysis


  Conducted to find out if there are meaningful differences between the experimental and control groups
• Psychologists consider differences to be statistically significant if there is less than a 5% chance of observing them if the groups did not actually differ from one another
• Experiments


  • Greatest strength is the ability to assert that any significant differences in the findings are caused by the independent variable
  • Random selection, random assignment, and a design that limits the effects of both experimenter bias and participant expectancy should create groups that are similar in composition and treatment
• If an experiment finds that watching a violent television program results in more violent behavior than watching a nonviolent program, researchers can safely say that watching violent television programs causes an increase in the display of violent behavior