Chapter 2: Studying Behavior Scientifically 

Scientific Principles in Psychology

  • Scientific Method:
    • Identify
    • Hypothesize
    • Test
    • Analyze
    • Build
  • Variable: quite simply, is any characteristic or factor that can vary
  • Operational Definition: defines a variable in terms of the specific procedures used to produce or measure it.
  • Archival Measures: which are records or documents that already exist
  • Informed Consent:  before people agree to participate in research, they should be informed about:
    • The study’s purpose and procedures
    • The study’s potential benefits
    • Potential risks to participants
    • The right to decline participation and withdraw at any time without penalty
    • Whether responses will be confidential and, if not, how privacy will be safeguarded

Methods of Research

  • Descriptive Research: seeks to identify how humans and other animals behave, particularly in natural settings
  • Case Study: an in-depth analysis of an individual, group, or event
  • Naturalistic Observation: the researcher observes behavior as it occurs in a natural setting, and attempts to avoid influencing that behavior
  • Survey Research: information about a topic is obtained by administering questionnaires or interviews to many people
  • Population: consists of all the individuals who we are interested in drawing a conclusion about
  • Sample: which is a subset of individuals drawn from the larger population
  • Representative Sample: is one that reflects the important characteristics of the population
  • Random Sampling: every member of the population has an equal probability of being chosen to participate in the survey
  • Correlation Coefficient: a statistic that indicates the direction and strength of the relation between two variables
  • Positive Correlation: means that higher scores on one variable are associated with higher scores on a second variable
  • Negative Correlation: occurs when higher scores on one variable are associated with lower scores on a second variable
  • Experiment the researcher:
    • Manipulates (i.e. controls) one or more variables
    • Measures whether this manipulation influences other variables
    • Attempts to control extraneous factors that might influence the outcome of the experiment
  • Independent Variable: the factor that is manipulated or controlled by the experimenter
  • Dependent Variable: the factor that is measured by the experimenter and that may be influenced by the independent variable
  • Experimental Group:  is the group that receives treatment or an active level of the independent variable.
  • Control Group: is not exposed to the treatment or receives a zero-level of the independent variable.
  • Random Assignment:  a procedure in which each participant has an equal likelihood of being assigned to any one group within an experiment
  • Counterbalancing:  a procedure in which the order of conditions is varied so that no condition has an overall advantage relative to the others

Threats to the Validity of Research

  • Internal Validity: represents the degree to which an experiment supports clear causal conclusion.
  • Confounding of Variables: means that two variables are intertwined in such a way that we cannot determine which one has influenced a dependent variable.
  • Placebo: refers to a substance that has no pharmacological effect
  • Placebo Effect: people receiving a treatment show a change in behavior because of their expectations, not because the treatment itself had any specific benefit
  • Double-Blind Procedure: in which both the participant and experimenter are kept blind as to which experimental condition the participant is in
  • External Validity: which is the degree to which the results of a study can be generalized to other populations, settings, and conditions
  • Replication:  is the process of repeating a study to determine whether the original findings can be duplicated

Analyzing and interpreting Data

  • Mode:  is the most frequently occurring score in a distribution
  • Median: the point that divides a distribution of scores in half when those scores are arranged in order from lowest to highest
  • Mean: is the arithmetic average of a set of scores
  • Standard Deviation:  takes into account how much each score in a distribution differs from the mean
  • Inferential Statistics:  tell us how confident we can be in making inferences about a population based on findings obtained from a sample
  • Statistical Significance: means that it is very unlikely that a particular finding occurred by chance alone
  • Meta-analysis: a statistical procedure for combining the results of different studies that examine the same topic