Non-experimental designs

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Non-experimental designs
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Outline

• Experimental vs. non-experimental research
• Four kinds of non-experimental research
• Observational research
• Archival research
• Case studies
• Surveys

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1. Experimental vs. non-experimental research

• Experimental research requires exerting control.

• Experimenters exert control through manipulation
  and assignment

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1. Experimental vs. non-experimental research

• Manipulation

• researcher systematically varies conditions
  under which participants perform task
• treatments

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1. Experimental vs. non-experimental research

• Manipulation
• Assignment

• researcher decides who gets which treatment

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1. Experimental and non-experimental research
compared

• Non-experimental research allows researcher much
  less control

• No assignment
• In many cases, no manipulation

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1. Experimental and non-experimental research
compared

• Four approaches
• Observational

• Recording ongoing behavior without trying to
  influence it.

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1. Experimental and non-experimental research
compared

• Four approaches
• Observational
• Archival

• Testing a hypothesis using data that the
  researcher did not collect

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1. Experimental and non-experimental research
compared

• Four approaches
• Observational
• Archival
• Case study

• Researcher carries out very detailed examination
  of individual cases

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Experimental and non-experimental research
compared

• Four approaches
• Observational
• Archival
• Case study
• Survey

• Researcher collects information on beliefs,
  attitudes, preferences, behaviors, and their
  correlations.

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Observational Research

• The researcher observes behavior without
  influencing it.
• Goals

• to describe behavior as it naturally occurs

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Observational Research

• The researcher observes behavior without
  influencing it.
• Goals

• to describe behavior as it naturally occurs
• to assess relationships among variables present

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Observational Research

• Four approaches to non-experimental research
• Observational
• Archival
• Case study
• Survey

• Four approaches to observation
• Naturalistic observation
• Participant-observer research
• Structured observation
• Field experiments

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Observational
Archival
Case Study
Survey
Naturalistic
Participant- observer
Structured observation
Field experiments
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Naturalistic Observation

• Observing phenomena that cannot be created in
  lab, for practical or ethical reasons

• Effects can be observed when such events occur
  naturally

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Naturalistic Observation

• Physical trace measures
• e.g., how well-thumbed is a book?
• Where do paths through the snow go?

• Reactivity
• subjects react to the presence of the observer

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Naturalistic Observation

• Example effect of early childhood isolation on
  later psychological development.

• We cant isolate children to study them
• But we can use naturalistic observation when we
  discover such cases

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Naturalistic observation

• Candland (1993) descriptions of feral children
  (raised outside human cultures)
• Curtiss (1977) case studies of children
  subjected to unusual isolation by parents (e.g.,
  Genie)

• Spitz (1965) observation of institutionalized
  children
• Showed effects of deprivation of stimulation
  during infancy and early childhood

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Observational Research

• Four approaches to observation
• Naturalistic observation
• Participant-observer research
• Structured observation
• Field experiments

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Participant-observer research

• Observer joins a group for the purpose of
  studying group members

• Undisguised vs. disguised
• Why use disguised observation?
• Access to behavior and situations

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Participant-observer research

• Observer joins a group for the purpose of
  studying group members

• Potential cost to objectivity
• Stockholm syndrome

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Observational Research

• Four approaches to observation
• Naturalistic observation
• Participant-observer research
• Structured observation
• Field experiments

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Structured observation

• Researcher exerts some control
• Eleanor Gibsons visual cliff studies
• Piagets studies

• Replication depends upon following exactly the
  same procedures

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Observational Research

• Four approaches to observation
• Naturalistic observation
• Participant-observer research
• Structured observation
• Field experiments

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Field experiments

• Researcher manipulates one or more variables in
  a natural setting to determine effect on behavior

• One end of the intervention non-intervention
  continuum

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Field experiments example

• Crusco Wetzel (1984)
• effect of touching on restaurant customers

• waitresses worked as confederates
• tip amount was dependent variable

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Field experiments example

• Crusco Wetzel (1984)
• Compared No Touch condition with Fleeting Touch
  and Shoulder Touch conditions

• Men tipped more than women
• Both men and women tipped more after being
  touched at some point during their meal.

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Observational Research

• Four approaches to non-experimental research
• Observational
• Archival
• Case study
• Survey

• Testing a hypothesis using data that the
  researcher did not collect

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b. Archival Research

• Archival records are a rich source of data
• No possibility of reactivity
• Often very inexpensive approach

• Government files
• Corporations
• Universities
• Newspapers
• Google cache
• Internet wayback machine

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b. Archival Research an example

• Lau Russell (1980)
• Tested external validity of laboratory findings
  on causal attributions

• People make internal attributions for success
  and external attributions for failure

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Lau Russell (1980)

• Sports pages in 8 daily newspapers
• Found 594 explanations for success and failure
  involving 33 sports events

• Proportions of internal attributions
• success 75
• failure 45

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Case Studies

• Intensive studies of individual cases.
• Strength you learn a lot about the case studied
• Weakness results may not generalize

• Well come back to this topic when we look at
  Single-Subject Experiments.

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Surveys - Definition

• A procedure for systematically collecting data
  on attitudes, preferences, knowledge, or behavior
  by asking people questions.

• The answers provide information about the
  group(s) that those people represent.

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d. Surveys

• Use surveys when
• You want data regarding a large group of people
  (a population)
• Measuring whole population is too expensive in
  time, money or other resources

• Population all the cases of interest

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Surveys

• Well look at surveys in greater detail in the
  next lecture