Theory and Data in Psychology

1
Theory and Data in Psychology

• What is a theory?
• Theories at multiple levels
• How we know when were wrong
• Hypotheses/Predictions --gt Confirmation/Disconfirm
  ation
• Cant prove a theory
• Falsifiability
• Examples of Theory-Testing Process

2
Introduction

• Fixing a light-bulb
• Checking possibilities
• One possibility at a time
• Hypothesis driven

3
A True Experiment

• Manipulate or systematically change the values of
  one variable while holding everything else
  constant
• Old light bulb vs new
• Old reading program versus new program

4
From an experiment or study ---gt Theory
5
Theory

• Unfortunate connotations--e.g. an idea in
  someones head
• A hunch or a guess is not a theory
• Sometimes opinion mistaken for theory and
  psychology dismissed as just a lot of theories

6
Theory as General Principles

• Light bulb scenario flip a switch and the bulb
  lights up--empirical observation
• But whats the explanation?
• Generality
• Definition A statement or set of statements that
  describes the underlying general principles for
  some phenomenon or class of phenomena

7
Structures Processes

• Structures
• electrons and conductors
• words and concepts
• Processes
• flow of electrons (current)
• assocations between concepts (e.g. spreading
  activation)

8
Why?

• Allows us to relate one event to another--to
  organize our knowledge
• Allows us to explain and predict
• Allows us to use our knowledge

9
The Ladder of Principles
10
Hierarchies

• Local or low level theories--limited class of
  phenomena (e.g. word recognition or light bulbs)
• High Level or General theories--wider class of
  phenomena (e.g. reading comprehension or
  electromagnetic theory)

11
General Principles in Psychology

• Physics versus Psychology
• General principles by which to explain (e.g.
  memory, learning, or depression)
• Observation repeating a name improves memory
• Principle of the association or a retrieval cue

12
Knowing When Were Wrong Testing Our Theories

• How do we test a theory?
• Theory-Data Cycle
• The Falsifiability Requirement
• The Weight of the Evidence

13
Testing Theories

• Observations gtgt Tentative Explanation or Theory
• Test theory with further observation (e.g.
  experiment or other study)
• How? Derive a prediction or hypothesis about the
  results of an experiment or study
• If theory X is correct then Y should happen gt run
  a study and observe whether Y happens

14
Prediction Disconfirmed

• Something is wrong. What?
• Perhaps we did the study wrong
• Translation of theory into hypotheses or
  predictions flawed Logic wrong
• Measurement problems
• Implementation flawed
• Theory wrong or more limited than thought

15
Prediction Confirmed

• Have we proved our theory? Absolutely not!
• Theory passed the test not disconfirmed--gt
  additional confidence in theory
• Confounds--X may have happened b/c of s.t. else
• Other theories make similar predictions
• May rule out alternative theories--if they made
  different predictions (indirect evidence)
• Counter-intuitive predictions

16
Summary

• When a prediction is disconfirmed gtgt clear
  evidence that something is wrong, either with the
  theory or the study
• If a prediction is confirmed then confidence in
  or support for theory increases.
• Theories never proven.

17
The Theory-Data Cycle
18
Falsifiability
19
Falsifiability Criterion

• In order to know if our theory is right we must
  test it
• Some theories cant be tested--they can be
  neither supported or not supported
  (unfalsifiable)
• If cant be falsified, no explanatory power
• Stanovich example

20
The Weight of the Evidence
21
The Weight of the Evidence

• A single study does not prove a theory nor does
  it really disconfirm the theory
• A question of accumulating evidence
• Is the evidence of one type or varied?
• Theory can have much evidence in its favor and
  yet new evidence may increase overturn
• A strong theory is well-supported not proven

22
Three Case Studies

• Harlow
• The Apathetic Bystander
• Therapeutic Touch

23
Harlows Experiment
24
Background to study

• Babies form strong attachments to adult
  caretakers. Why? Explanation?
• Cupboard Theory (reduce hunger)
• Underlying cupboard theory is more general theory
  Drive Reduction Theories

25
Harlows Experiment

• Test Cupboard Theory gt 1st consider alternative
  explanations/theories
• Contact Comfort Theory
• In nature, these two variables confounded
• Harlow separated them (wire vs terrycloth)
• Which mother preferred according to each theory?

26
Harlows Findings

• Babies clung to terrycloth mother 12-18 hours/day
• So what? Is theory proved?
• Further tests

27
Two Important Points

• Cupboard Theory a good theory b/c testable--could
  derive a prediction and check theory
• Idea tested at multiple levels

28
Disconfirmation at Multiple Levels
29
The Apathetic Bystander

• Terrifying failures of human compassion?
• Large cities anonymity
• Internal state or situational explanation?
• Smoke-Filled Room Experiment Analog (Latané
  Darley, 1970)

30
Smoked-filled Room Experiment

• Classic series of experiments
• The setting a waiting room
• Question Will subjects report emergency or not
• Independent variable?
• Dependent variable?
• Findings

31
Smoked-Filled Room Experiment
32
Summary

• Follow-up studies gt different settings and
  different emergencies
• Implication safety in numbers may be wrong
• Prediction confirmed by data AND
  counter-intuitive (therefore stronger)
• Personality factors equated by randomization
• General principle affirmed--external factors can
  be more important than personality factors

33
Therapeutic Touch
34
Weight of the Evidence Revisited

• No single experiment makes or breaks a
  theory--specific findings make contact with other
  studies
• Harlows finding (nutrition alone insuff)
  supported by other work (see Mook, pp. 119-123)
• Bystander-intervention studies (see chpt 12)
• Cross-checks

35
From Big Questions to Small Studies--And Back
Again

• Single study--limited scope, small, specific,
  answerable questions
• Operationalizing a variable--specific choices
• External Validity (Generalizability) Issue
• Then whats the point of these studies?

36
Three Caveats

• Specific study as example of more general and
  important processes
• Experiments do not Stand Alone
• Experiment can test a theory at many levels at
  once