Student fears about ideas
• Not “great”
• Not original
• Do we have the equipment?
• Level of complexity
• Plan statistics in advance
• Feasibility
© 2001 Dr. Laura Snodgrass, Ph.D.
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Where do ideas come from?
• My experiences
Find out why this happens?
Notice peculiarity
Attempts to replicate
Casual discussion of ability of blind
Student Questions
Why women don’t use their spatial ability to solve problems?
© 2001 Dr. Laura Snodgrass, Ph.D.
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Where ideas come from
• Existing theories make testable predictions
• Competing theories
• Investigating functional relationships
• Observation
• Replicate with small changes
• Practical Problems
• Journal articles end with suggestions
• Serendipity
© 2001 Dr. Laura Snodgrass, Ph.D.
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What makes a good hypothesis?
• ROT test
Repeatable
Observable (measurable)
Testable
• Specific and limited to a population
• State a relationship
© 2001 Dr. Laura Snodgrass, Ph.D.
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Which of the following are “good” hypotheses?
• Beagles are smarter than poodles
•
The US would not have become involved in WWII if Japan hadn’t
bombed Pearl Harbor
•
Soccer players are better athletes than football players
•
College students consume more beer per person than any other
group
•
Our actions sometimes reflect conscious intentions, but are
usually governed by subconscious urges
•
African Violets grow better in filtered than direct sunlight
•
Diamonds are a good investment
© 2001 Dr. Laura Snodgrass, Ph.D.
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“good” hypotheses?
• Hondas are better cars than Toyotas
• You learn more when studying for an essay exam than
for a multiple choice exam
• Religion makes people happy
• The Oklahoma City bombing was more traumatic than
the TWA plane crash
• Ginkgo improves your memory
• Housepets make people feel better.
© 2001 Dr. Laura Snodgrass, Ph.D.
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Theory
Def: Statement about a not directly observable relationship
• Cycle of reasoning
Observation leads to induction leads to theory leads to
deduction leads to observation
Induction - takes you from the specific to the general
observe specifics and theorize about what is generally true
Deduction - from the general to the specific
We test theories by making predictions about specifics
© 2001 Dr. Laura Snodgrass, Ph.D.
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Types of theories
• Descriptive - names without explanation
• Analogical - analogy to a physical model
• Quantitative - mathematical or probabilistic relationship
© 2001 Dr. Laura Snodgrass, Ph.D.
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What makes a good theory?
• Accounts for most of the data
• Parsimony - “Occam’s Razor”
the simplest explanation is the best
• Precision
• Testable
• Predictive
• Generalizable
© 2001 Dr. Laura Snodgrass, Ph.D.
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Why use theory?
• Organizes the data
• Provides a framework to explain facts
• Suggests future research
•
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• Provide answers to applied problems
• Generates predictions
© 2001 Dr. Laura Snodgrass, Ph.D.
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Why do a literature search?
• Your experiment may already be there
• Find the methods others have used
What equipment did they use?
Questions about timing
Borrow successful stimuli
Who were their participants
• Look at other people’s failures (can save you time)
• Fit your idea into an organized body of knowledge
© 2001 Dr. Laura Snodgrass, Ph.D.
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How to do a literature search
• Books - good general overview, but can have strong
author bias
• Review Articles - Psych Bulletin, Psych Review
• Tree backwards - start with most recent article or
textbook and then look up their references
• Psych Lit - computerized search
© 2001 Dr. Laura Snodgrass, Ph.D.
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