BHS 20401 Methods in Behavioral Sciences I

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BHS 204-01Methods in Behavioral Sciences I

• Nancy Alvarado, Ph.D.

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What is an Experiment?

• A sample experiment the Pepsi Challenge.
• Start with a set of questions
• Can people really tell the difference between
  Pepsi and Coke?
• How is preference for one or the other cola
  related to being able to tell the difference?
• Does it matter which order you drink the two
  flavors in?
• Coke first vs Pepsi first

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Finding Answers

• How do you answer the questions youve come up
  with?
• Experimental design for Pepsi Challenge
• Get a group of people
• Let them taste the two kinds of cola
• Half taste Pepsi first, half taste Coke first
• Ask them questions
• Which is Pepsi?
• Which do you prefer?

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Making Predictions

• A researcher generally has some idea about how
  the experiment will turn out
• Predictions come from theories, from observations
  of real life behavior, and from the
  experimenters own experience and beliefs.
• State predictions in terms of the experiment
• People will prefer Pepsi, people can tell which
  is which, order will not make a difference.

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Run the Experiment

• Collect data
• Analyze the data
• Descriptive statistics summarize data
• Inferential statistics test your results
  against what might have occurred by chance.
• Use the data to test the predictions
• How many people ID and prefer Pepsi vs Coke?
• Did order of tasting affect the choices?

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Present the Findings

• An experiment is wasted if its results are not
  communicated to the public and to the scientific
  community.
• Vehicles for communicating
• Conferences
• Professional journals
• Public press releases, TV, radio, popular books

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Questions Lead to More Questions

• Does it matter whether the Pepsi is tasted cold
  or warm?
• How do people identify it?
• Bubbles amount of carbonation?
• Sweetness does Pepsi have more sugar?
• Are factors beyond taste important to preference?
• Brand loyalty, image (rebels drink Classic Coke)?

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Terminology

• Subject or participant a person who provides
  information or data in a study.
• Dependent variable what is measured during your
  study.
• Independent variable what is manipulated during
  your study.
• Condition which group a person is assigned to
  in the study.

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What is an Experiment?

• A controlled situation in which the researcher
  manipulates at least one variable in order to
  observe the effect of that change on subject
  behavior.
• There must be at least one independent variable
  that is manipulated by the experimenter.
• There must be at least one dependent variable
  that is measured by the experimenter.
• Experiments can tell you about causes.