ch.2

• hindsight bias - tendency to believe, after learning an outcome, that we would have foreseen it - the i-knew-it-all-along phenomenon
• overconfidence - tendency to think we know more than we do
• theory - explanation using integrated set of principles that organizes observations and predicts behaviours or events
• hypothesis - a testable prediction often implied by a theory
• operational definition - statements of the exact procedures used in a research study to define the research variables
• replication - repetition of the methods used in a previous experiment to see whether the same methods will yield the same results
• descriptive methods - describe behaviours by using case studies, surveys, and naturalistic observations
• correlational methods - associate different variables and see if they are related
• experimental methods - manipulate variables to discover their effects
• case study - descriptive technique where an individual or group is studied in depth to reveal universal principles
• naturalistic observation - descriptive technique of observing subjects in their natural environments without manipulating or controlling the situation
• survey - descriptive technique in less depth for obtaining self-reported behaviours by questioning
• wording effect - when the wording of a question can influence the answers given
• sampling bias - flawed sampling process that produces an unrepresentative sample
• population - all those in a group being studied from which samples may be drawn
• in order to select a sample, one must first identify the population from which the sample will be selected
• random sample - sample that fairly represents a population because each member has an equal chance of inclusion
• correlation - measure of how two factors are related
• correlation coefficient - statistical measure of the relationship between two factors - -1 to +1
• the closer the score gets to -1 or +1, the stronger the correlation
• variable - anything that can vary and is feasible and ethical to measure
• scatterplot - a graphed cluster of dots, each of which represents the values of two variables

  • slope suggests direction of the relationship between variables
  • amount of scatter suggests strength of the correlation - little scatter indicates high correlation
• correlation does not prove causation
• illusory correlation - perceiving a relationship where no correlation exists or perceiving a stronger-than-actual relationship
• regression toward the mean - tendency for extreme or unusual scores or events to fall back towards the average
• experiment - manipulation of an independent variable under controlled conditions and measurement of its effects on a dependent variable
• experimental group - the group in an experiment that receives the treatment or IV
• control group - the group in an experiment that doesn't receive the treatment or IV
• random assignment - division of the sample into experimental and control groups so that every individual has an equal chance of being put into any group
• double-blind procedure - research design in which neither the experimenter nor the participant know who is in the experimental or control group
• placebo effect - caused by expectations alone; response to the belief that the IV will have an effect rather than the actual effect of the IV
• placebo - a physical or psychological treatment given to the control group that resembles the treatment given to the experimental group, but that contains no active ingredient
• independent variable - factor that is manipulated - the cause
• dependent variable - factor that is measured - the effect
• confounding variable - factor that cause the difference between the experimental and control group other than the IV
• validity - extent to which an experiment measures or predicts what it is supposed to do
• informed consent - participants must be given information about a study to enable them to choose whether they wish to participate
• debriefing - participants must receive a full explanation of the research when their involvement is done
• descriptive statistics - numerical data used to measure and describe characteristics of groups
• histogram - bar graph depicting a frequency distribution