Theories and Hypotheses

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Theories and Hypotheses
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Assumptions of science

• A true physical universe exists
• Order through cause and effect, the connections
  can be discovered
• Knowledge is always incomplete, theories are
  always tentative.
• Facts are observed data - in psychology tend to
  be behaviors observable behavior
• Constructs are inferred intermediary processes
  (e.g. memory)

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• A construct is not a fact. Construct is inferred
  from the behavior , then used a basis for
  predicting new behavior to be observed. Science
  involves interaction between empirical
  observation and rational abstraction.

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Paradigms

• Overarching scheme , worldview, collection of
  theories and conventions
• Methodological decisions may be affected by the
  research tradition
• Paradigm tells you what to study
• Normal science - incremental quantitative steps
• Paradigm shifts -qualitative or revolutionary
  change

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Paradigm shifts

• Old paradigm fails to account for important
  problems
• IF there is another and it does a better job
  then change paradigms- but if no good alternative
  then hang on to a bad theory

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Paradigm shifts

• Resist change group dedicated to old way
• Commitment to ongoing research
• Uncertainty about future direction
• How do I fit in new paradigm?
• Two or more paradigms may coexist but not
  communicate with each other

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• Foundational approach (Popper) method counts.
  Falsification of hypotheses based on logic/rigid
  test with view to throwing out theory
• In practice scientists do not have as a goal the
  falsification of their ideas
• If we threw out every rejected hypothesis science
  would be poorer
• Kuhn science is best understood by examining
  how scientists behave in practice

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Caveats and excuses

• Theories rarely abandoned because of one
  conflicting finding.
• Especially long standing theories.
• Beginning theories also may get more slack
  because they not fully refined. if we reject
  everything we have nothing.
• Tend to look for problems in method or experiment
  

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• widely held view that the alternative successor
  hypothesis should be able to explain all that the
  displaced theory did plus new stuff.
• never observed in practice - it takes time to
  develop a complex theory - often initially it
  cannot explain all but develops with time

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Theory

• set of logically consistent statements about
  behavioral phenomenon
• best summarizes existing knowledge
• organizes knowledge in form of laws (precise
  statements of relationship among variables)
• provides a tentative explanation
• serves as the basis for making predictions
• highly explicit and detailed and testable

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• No scientific theory is a fact.
• This does not imply that a theory is just a hunch
  or that scientists dont actually know anything
  so they just have a theory.
• A good theory is a treasure.

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A Good Theory

• Is falsifiable/testable
• Is in harmony with other hypotheses in the field
• Is logically simple no extra assumptions
• Should yield deductions (have consequences)
• Is parsimonious simple better than complex
  Occams razor and Morgans canon
• A theory produces predictions and so influences
  how you study

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Occoms razor Entities should not be multiplied
unnecessarily

• Isaac Newton stated the rule "We are to admit no
  more causes of natural things than such as are
  both true and sufficient to explain their
  appearances."
• The most useful statement of the principle for
  scientists is -
• When you have two competing theories which make
  exactly the same predictions, the one that is
  simpler is the better."

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Morgans canon

• In no case may we interpret an action as the
  outcome of the exercise of a higher psychical
  faculty, if it can be interpreted as the outcome
  of one which stands lower in the psychological
  scale

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Problems

• Circular reasoning
• All or none bias completely true/false under
  all conditions
• Bias of similarity /difference
• Bias of language or culture

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Logic of testing

• Logical process of deduction reasoning from
  general statements toward some specific event.
• If theory A correct then event X should occur
  with some probability greater than chance.
• The prediction is the hypothesis.
• Induction is the logical process of reasoning
  from the specific (individual experimental
  outcome) to the general (theory).

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Impossible to prove a theory true.

• If bird is a crow then it will be black.
• a) Here is a black bird it must be a crow
• b) Here is a yellow bird it cannot be a crow
• We say that an experiment supports or is
  consistent with theory but does not prove theory
  right.

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• Hypothesis a prediction about the outcome of an
  experiment.
• Scientific hypothesis generated by a theory.
• Statistical hypothesis concrete description of
  one or more summary aspects of population(s).
  Grow out or are implied by scientific hypotheses