Experimental Psychology

1
Experimental Psychology

• What is Experimental about it?
• Psychology as a Science
• Psychology as an Experimental Science
• Psychology as an Observational Science

2
Rene Descartes The Skeptical Inquirer

• How do I know what I believe to be true?
• The need to question the basis for ones beliefs
  and knowledge

3
Ways of Knowing

• Knowing by Belief or Intuition
• Knowing by Authority
• Knowing by Reason
• Knowing by Common Sense
• Knowing by Scientific Inquiry

4
Knowing by Belief

• Examples
• Knowing that sugar causes hyperactivity
• Believing in alien abductions
• Advantages
• Sense of certainty
• Provides understanding of the world
• Disadvantages
• Belief may be wrong
• Belief may not be shared by others
• No way to resolve differences between conflicting
  beliefs

5
Knowing by Authority

• Examples
• Mt. Everest is tallest mountain
• Your brain weighs about 3 pounds
• Richard Nixon is dead
• Advantages
• Quick
• Easy to acquire
• No responsibility for knowledge
• Disadvantages
• Authority may be wrong
• No way to resolve differences between conflicting
  authorities

6
Knowing by Reason

• Examples
• Knowing that 2 apples remain if 3 are taken from
  5
• Knowing that bumblebees cannot fly
• Advantages
• Certainty of conclusion
• Disadvantages
• Reaching conclusion may be difficult
• Premises may be in error, and therefore
  conclusion will be in error

7
Knowing by Common Sense

• Examples
• Knowing that the earth is round
• Knowing that boys will fight
• Advantages
• Knowledge is shared by others
• Knowledge is easily accessible
• Knowledge can be tested against experience
• Disadvantages
• Knowledge may be in error
• Knowledge may be self-contradictory

8
Knowing by Scientific Inquiry

• Examples
• Knowing that adrenalin increases heart rate
• Knowing that women have a double standard
• Advantages
• Knowledge can be shared by others
• Basis for knowledge can be evaluated and
  differences in claims can be resolved
• Disadvantages
• Knowledge is not certain
• Knowledge can take a long time to acquire

9
A Brief History of Experimental Psychology

• The personal equation in astronomy
• Kinnebrook Maskelynne
• von Helmholtzs measure of nerve speed
• The measurement of touch and muscle sense
• Weber Fechner

10

• Measurement of attention
• Span of apprehension
• Measurement of memory
• Ebbinghaus
• Measurement of concept acquisition
• Hovland Bruner, Goodnow Austin
• Measurement of cognitive development
• Piaget Conservation tasks
• Measurement of bystander intervention
• Darley Latane

11
Goals of Science

• Description
• Prediction
• Control
• Understanding

12
Features of Science

• Systematic empiricism
• Publicly verifiable knowledge
• Solvable problems
• The falsifiability criterion
• Utility as truth

13
Systematic Empiricism

• What is empirical?
• Based on observations of the world
• Examples gorillas, And No Birds Sing, Clever
  Hans
• What is systematic?
• Sampling is specified
• Recording is systematic

14
Public Knowledge

• Results can be obtained by someone else using the
  same methods
• no special talents
• Confirmable by others
• interobserver reliability
• Use of external memory
• Record does not depend on a memory

15
Solvable Problems

• Problems can be approached using currently
  available methods
• finding treatments for AIDS
• localizing a brain tumor
• Some problems cannot be solved
• video-recording someones dream
• preventing hurricanes

16
Falsifiability Criterion

• Logical analysis of arguments
• Valid arguments
• Internal Validity
• External Validity
• Logical Forms
• Modus ponens
• modus tollens
• affirming the consequent
• denying the antecedent

17
Falsifiability Criterion

• Karl Poppers analysis
• Hypothesis testing
• seeking contrary outcomes
• the importance of negative evidence
• when positive evidence is important

18
Science as a Utilitarian Endeavor

• Truth versus truth
• The necessary uncertainty of induction
• The constructed reality of science

19
Fallibility of Science

• Thomas Kuhn and the structure of scientific
  revolutions
• Science as a human enterprise

20
Psychology as a Science

• Complexity of causes
• Marker variables
• gravity
• colds
• personality

21
A Case Study Clever Hans

• The Phenomenon
• Oskar Pfungsts Analysis
• Observation of phenomena
• Analysis of controlling conditions
• Control of conditions
• Laboratory verification
• Extension of the analysis