Chapter 1

• Hindsight bias


  Tendency to believe, after knowing the outcome, that one would have been able to forsee it
• Critical thinking


  Thinking that does not just blindly accept arguments and assertions, but rather, assesses and tests them to see if their stances are correct
• Theory

  An explanation using an integrated set of principles that organizes observations and predicts behaviors or events
• Hypothesis 


  A testable prediction, often implied by a theory.
• Operational definition 


  A statement of the procedures (operations) used to define research variables. For example, human intelligence may be operationally defined as what an intelligence test measures
• Replication 


  Repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances.
• Much of our early knowledge of the brain came from case studies on patients with damage to very specific regions of the brain
• Case study


  When one or a few individuals are studied in-depth in the hopes of learning information that can be applied universally
• Survey


  A technique for learning about the self-reported behaviors and attitudes of a particular group, usually by questioning a randomly selected and representative subjects
• Population 


  All the cases in a group being studied, from which samples may be drawn. (Note: Except for national studies, this does not refer to a country’s whole population.)
• Random sample 


  a sample that fairly represents a population because each member has an equal chance of inclusion
• Naturalistic observation 


  observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation.
• Correlation


  a measure of the extent to which two factors vary together, and thus of how well either factor predicts
• Correlation coefficient 


  a statistical index of the relationship between two things (from −1 to +1).
• Scatterplots


  A graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship between the two variables. The amount of scatter suggests the strength of the correlation (little scatter indicates high correlation).
• Illusory correlation


  Perceived but illusory correlation
• Experiment 


  A research method in which an investigator manipulates one or more factors (independent variables) to observe the effect on some behavior or mental process (the dependent variable). By random assignment of participants, the experimenter aims to control other relevant factors.
• Random assignment 


  Assigning participants to experimental and control groups by chance, thus minimizing preexisting differences between those assigned to the different groups
• Double-blind procedure 


  An experimental procedure in which both the research participants and the research staff are ignorant (blind) about whether the research participants have received the treatment or a placebo. Commonly used in drug-evaluation studies.
• Placebo effect 


  Experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which the recipient assumes
• Experimental group 


  In an experiment, the group that is exposed to the treatment, that is, to one version of the independent variable.
• Control group 


  In an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment
• Independent variable 


  The experimental factor that is manipulated; the variable whose effect is being studied.
• Dependent variable 


  the outcome factor; the variable that may change in response to manipulations of the independent variable
• Normal curve (normal distribution) 


  A symmetrical, bell-shaped curve that describes the distribution of many types of data; most scores fall near the mean (68 percent fall within one standard deviation of it) and fewer and fewer near the extremes