Basics of Scientific Inquiry

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Basics of Scientific Inquiry
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Common sense claims

• Common sense claims are often hunches based on
  anecdotal evidence e.g. most people would not
  hurt another human being just because an
  authority figure told them too.
• Milgrams (1966) famous experiment into
  conformity.
• Approx 70 of those tested gave electric shocks
  to what they believed was another test subject,
  at a level high enough to kill them.
• Before carrying out the research, Milgram had
  asked other psychologists whether he should go
  ahead with the experiment. He was told that
  nearly all participants would withdraw before
  causing any pain.

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Three lessons from Milgram

• Skepticism is valuable.
• Careful observation under controlled conditions
  is very important.
• Observer expectancy results are real and are
  research cancer.
• Clever Hans wasnt so clever, after all.

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What Is Scientific Inquiry?

• Four goals of scientific inquiry
• Description (what happens)
• Prediction (when it happens)
• Causal control (what causes it to happen)
• Explanation (why it happens)
• How would we apply these goals to the study of
  the effects of alcohol intoxication?

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• An open mind and good imagination are not enough.
  Research in the psychological sciences requires a
  skeptical attitude and objective methodology.

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Falsifiability

• The case of blood-letting
• For a theory to be useful, the predictions drawn
  from it must be specific.
• Tell us what will happen
• Tell us what will not happen
• How would we test for my ability to mind read?

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The Bottom Line

• Progress occurs in science when a theory does not
  predict everything.
• Rather, science benefits from specific
  predictions about phenomena, made in advance.
• Falsifiability is liberating making mistakes
  furthers progress

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Falsifiable or Unfalsifiable?

• Pepsi tastes better than Coca Cola
• Psychics can speak to the dead
• Aliens abduct us, do medical experiments on us
  and then return us, leaving no evidence

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Pseudoscience

• A theory with the empirical trappings of real
  science, including a system of theoretical
  concepts and a wealth of corroborating evidence.
• But a pseudo-science has built-in defense
  mechanisms against possible refutation.
• The Freudian theory provides an interpretation
  for every conceivable symptom of the patient.
• Its predictions therefore can never be refuted.
• http//www.youtube.com/watch?vIWE5N8z2Aa4

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The Nature of Science

• Order there are regular patterns in events
• Determinism events have identifiable causes
• Empiricism theories should be based on publicly
  available evidence gathered through objective
  observation
• Parsimony explanations should explain as much as
  possible as simply as possible

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Ockham's Razor
A rule in science and philosophy stating that
entities should not be multiplied needlessly.
This rule is interpreted to mean that the
simplest of two or more competing theories is
preferable and that an explanation for unknown
phenomena should first be attempted in terms of
what is already known. Also called law of
parsimony.
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The Empirical Process
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Building a Psychological Science

• Facts
• objective statement, based on direct observation,
  reasonable people agree with
• Theories
• Interrelated set of concepts designed to explain
  existing facts generate new predictions
• Hypotheses Specific Predictions
• Predictions about new facts based on the theory

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The Methods of Psychological Science
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An Experiment Involves Manipulating Conditions

• Manipulating independent variables and measuring
  dependent variables helps to establish causal
  relationships
• Random assignment helps create equivalent groups

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Types of Reasoning
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Deductive Research

• A top down approach
• GENERAL SPECIFIC
• IF All oranges are fruit
• and all fruit grows on trees
• THEN oranges grow on trees
• Deductive process- Reasoning from general to
  particular. E.g. Start with a theory look for
  instances that confirm this (deduction).

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Inductive Research

• A bottom up approach
• GENERAL SPECIFIC
• Inductive process- Reasoning from particular to
  general E.g. Scientists may observe instances of
  a natural phenomenon and derive a general law
  (inductive)

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Inductive or Deductive?

• Dan is a liar so I predict that the next thing he
  says will be a lie
• Bubba has seen his puppy gnaw on shoes so he
  predicts that puppies always gnaw on shoes
• Robins have nested under Rays carport for 3
  years. He expects that they will nest there again
  this year.
• The gene for blue skin in fish also codes for
  aggression so Jane will not put her blue fish in
  with Elaines red fish.

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The Experiment
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Independent Variables are Manipulated by
Experimenters

• Experimenter control is the central feature of
  IVs
• IVs are NOT free to vary instead, they are
  fixed by design

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Dependent Variables are Measured in Relation to
IVs

• DVs are said to depend on, be effects of, or be
  caused by IVs
• DV in alcohol intoxication study?

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Identify the IV and DV

• Jack does an experiment to determine whether
  alcohol makes fish more aggressive
• Jane puts more water in the dough of her bread in
  order to make it rise better
• Martha gives her crying baby a popsicle because
  she thinks she may be teething
• Dr. Smith shows people violent movies and
  measures how quickly they eat a meal afterward
• Wanda puts one orchid in the sun and one in the
  shade because she wants to decrease growing time

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An Experiment Involves Manipulating Conditions

• Manipulating independent variables and measuring
  dependent variables helps to establish causal
  relationships
• Random assignment helps create equivalent groups

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List of Core Features of Experimental Methods

• Independent variables (IVs)
• Dependent variables (DVs)
• Random sampling from representative populations
• Random assignment to conditions or treatments
• Efforts to control or minimize
  extraneous/irrelevant factors

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Operational Definition

• The quantification of a variable that allows it
  to be measured
• Concepts in scientific theories must in some way
  be grounded in, or linked to, observable events
  that can be measured
• Preexisting bias problem

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Class Activity
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James Randi

• The Amazing Randi
• Paranormal 1 million dollar challenge
• http//www.youtube.com/watch?vNzwwMmNRIVc