The Basics of Experimentation:

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The Basics of Experimentation

• Concepts, Definitions and Examples

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The Debate What is learned?

• Behaviorists (e.g., Clark Hull)
  stimulus-response (S-R) associations only
  observable behavior can be studied
  scientifically.
• Cognitivists (e.g., Edward Tolman) S-S
  associations, such as the relations among distal
  cues that form cognitive maps, can be inferred
  from observable behavior.

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A process of elimination Place units (cells) in
the hippocampus respond to an animals location
within the environment, not to a specific sensory
stimulus, motor behavior or motivational
incentive.
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A Demonstration of Place Cell Firing
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The activity of multiple hippocampal neurons
(ensembles) during REM sleep matches the place
activity of the same neurons when the animal was
awake.
Are the animals dreaming of past places they have
experienced?
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Do rats and other mammals dream?
Some papers equate REM sleep with dreaming
sleep One function of REM sleep may be to help
consolidate memory of recent events
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Experimental variables

• Every experimental variable has two definitions
• Conceptual used in everyday language
• Operational used in conducting an experiment.
• Dreaming is conceptual and REM sleep is
  operational.

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Experimental variables

• Hypotheses are often stated in conceptual terms
  but experiments require operational definitions.
• How will you operationally define variables in
  your study?
• This is a critical step in setting up the Methods
  section.

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Operational definitions

• Experimental what was done to create the
  treatment conditions (IV).
• Measured What procedures were followed to
  assess the effect of the treatment (DV).

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Measured operational definitions

• How do you define spatial learning, especially if
  it is possible that animals may use a simpler
  form of stimulus-response (S-R) learning?

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Hypothetical Constructs

• Spatial learning is a hypothetical construct an
  unseen process that is postulated to explain
  behavior.
• The same construct variable can be defined in
  different ways in different experiments.

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Measured operational definitions

• In the water maze study
• Place response escaping to the hidden platform
  (S-S cognitive association).
• Cue response escaping to the visible platform
  (S-R association).

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Cue Response
Place Response
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Measured operational definitions

• In a different Water maze study
• A place response visiting the old location
  (spatial learning) before escaping to the visible
  platform (S-R learning) at a new location.
• A cue response not visiting the old location
  before escaping to the visible platform (S-R
  association).

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Cue Response
Place Response
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Measured operational definitions

• In a Plus Maze study
• Place response Turning left or right at the
  choice point depending the start location
  (spatial learning).
• Turning response Always turning left regardless
  of the start location (S-R association).

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Measured operational definitions

• Water maze
• A place response escaping to the hidden
  platform (S-S cognitive association).
• A cue response escaping to the visible platform
  (S-R association).

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Independent Variables (IV)

• What makes the IV independent?
• It is an aspect of the experiment that varies.
• It is the dimension that the experimenter
  manipulates.
• Its values are created by the experimenter.
• Its values are not affected by anything else that
  happens in the experiment.

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Dependent Variables (DV)

• What makes the Dependent variable dependent?
• It is an aspect of the experiment that varies.
• It is the dimension that the experimenter does
  not manipulate.
• It values depend on the effects of the IV.
• It is an objective measure of behavior that is
  observed in the experiment.

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Independent Variables (IV)

• What is the minimum number of levels of the IV in
  any experiment?
• 0
• 1
• 2
• 3
• 4

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Independent Variables (IV)

• Three kinds of IV
• Environmental variables (e.g., music)
• Task variables (hidden vs visible platform)
• Subject variables (sex or personality or learning
  strategy).

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Defining subject variables
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Two room protocol
Would fast place learners in room A also be good
latent learners in room B?
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Results
Fast place learners 2,3,4,6,9,10 Good latent
learners 2,3,7,8,9,12
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Inverse relation
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Assignment 4

• Finish your introduction!
• Read the room with a view paper and
• Identify independent and dependent variables
• Constructs
• Operational definitions
• Identify potential sources and types of
• Reliability
• Validity
• Identify potential threats to internal validity