PSYC-115 FA5 Lecture Notes - Lecture 4: Pupillary Response, Observer-Expectancy Effect, Demand Characteristics
13 Jun 2018
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January 26, 2018
Lecture 4: Methodology: Cautions and Caveats
●Perform the experiment:
○Conduct issues:
■Subject bias
●Ex: Giraldo Rivers (the effects of marijuana; there was no active
drug administered(marijuana without thc)) and stanley Schacter
(the effects of stimulants and depressants; for some the drug was
what was indicated; for other there was no active drug; for others
the drug was opposite of one expected(experimenters were actually
looking at the placebo effect))
●Definition-any bias that the subject brings into the experiment that
might impact the results
○Giraldo Rivers- marijuana causes pupillary dilation(it
doesn’t, darkness causes pupillary dilation); marijuana
makes you hungry; marijuana increases heart rate and
blood pressure
○Stanley Schacter- barbiturates slow you down;
amphetamine speeds you up; saline has no effect
●Explanation:
○Expectancies:
■Specific and general
■Conscious and unconscious
○Observation effects (Adamec)
○Demand characteristics (tend to please the investigator if
you know what’s being studied)
●Control (Single-Blind)
○The primary way to control for subject bias is to give little
information to the subject in terms of what is being done.
For example, one might indicate that a drug will be given
(or some manipulation is being made) but no information is
give to indicate what specific drug or manipulation will be
given or what effects might be expected
○Problems:
■If effect is produced, this gives information to the
subject
■Is it ethical to use placebo controls in studies?
