Experimental Psychology
PSY 433
Introduction
Super Brain Yoga
 http://www.youtube.com/watch?v=KSwhpF9iJSs
 Does it work? How can we find out?
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Find people who do it and test them.
Compare those who do it to people who don’t.
Better yet, assign people to do it and compare
them to a second group assigned to not do it.
Even better, have those not doing SB yoga do
some exercise that is similar.
 How does it work? Manipulate elements to
find the “active ingredient,” the mechanism.
Thinking Like a Monkey
 Jerry Adler, Smithsonian Magazine, January
2008
 Do monkeys assume that people act like
monkeys?
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Do monkeys have a “theory of mind” – the
ability to impute thoughts and intentions to
another individual?
How do you test what is going on in anyone’s
head, much less a monkey’s mind?
Dr. Laurie Santos
Associate
Professor of
Psychology
Yale University
Cayo Santiago
 An island off the coast of Puerto Rico that is a
sanctuary for rhesus monkeys.
Rhesus Monkeys
 One of 22 species of Macaques (primates,
ranging from Western Africa to Japan).
 Widely used in lab research.
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Young monkeys are typically used as subjects
because the adults are dangerous and
uncooperative.
This creates an artificial environment for
studying social and cognitive behavior.
 Free-ranging monkey colonies permit more
natural behavior to emerge.
A Rhesus Social Group
The Experiment
 Hypothesis – If monkeys attribute monkey
behavior to humans, they will treat humans
similarly to monkeys.
 The task – Food stealing and guarding
behavior occurs because monkeys will steal
unguarded food.
 Place an unguarded grape in reach of a
monkey and see if it will steal it when
unguarded.
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This works.
The Monkey Chooses
Theory of Mind
 First, one person places two grapes in two 3-
sided boxes and guards them.
 Second, the first person turns away while a
different person moves the grapes into two
different boxes.
 Third, the first person turns back and guards
the two boxes that no longer have grapes.
 Question: Will the monkeys recognize that
the person is not guarding the moved grapes
and attempt to steal them?
Setup for the Task
Person stands here to
guard the grapes
Grape
Grape
A
B
Monkey approaches here to steal
the grapes
C
Manipulation
Person stands here to
guard the grapes
A
Grape
Grape
B
C
Monkey approaches here to steal
the grapes
A More Difficult Test…
 Never both turn your backs on the monkeys
or they will rush the grapes.
 Trial 1 – the monkey languidly scratches itself
then turns and looks out over the rocks to the
sea.
 Trial 2 & 3 – no approach by the monkey.
 Trial 4 – the boxes blow over.
 Trial 5 – as soon as the grapes are displayed
the monkey walks away.
What Happened...
 Trial 6 – the monkey gets off its haunches
and walks swiftly toward the experimenter.
“Turn around” Santos calls. The student
pivots, pulls herself up to full height and
stares right at the monkey. It snarls
menacingly back at her. She shrieks and runs
to hide behind a colleague. The monkey
grabs both grapes and runs away, chewing.
 Conclusion – monkeys cannot make the
mental leap to a concept of “false belief.”
What if it had Worked?
 What would a successful outcome be?
 The monkeys can see the grapes.
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It appears as if all 3 boxes are being guarded.
There are 2 grapes, so a monkey without any
knowledge has a 50-50 chance of picking
either grape.
If the monkey understands that the person is
unaware of the grape’s positions, then it
should pick the moved grape (in a new
location) more often than the other grape.
Critiques of the Study
 Can monkeys select the moved grape more
often for some other reason?
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What were the experimenters wearing?
What else might the monkeys be thinking?
 Is it a problem that so many monkeys are
uninterested?
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When the task is too difficult to do at all, are
the results meaningful?
Perhaps a different task is needed.
Marc Hauser at Harvard
http://www.nytimes.com/2010/08/14/education/14harvard.html?_r=2&hp
Why We Do Research
 Basic Research -- We may not care about
monkeys but we care about theories of
evolution and the innateness of human social
behavior.
 Applied Research -- We care about what
works, and other practical questions.
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Super Brain Yoga
Abstinence-only sex education
Evidence-based educational practices – how
to study
Does Abstinence Education Work?
 Impacts of Four Title V, Section 510
Abstinence Education Programs, Final Report
(April 2007), Mathematica Policy Research,
Inc.
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http://www.mathematica-mpr.com/publications/PDFs/impactabstinence.pdf
 The goal of abstinence education is to
encourage teens to abstain from sex outside
marriage, thereby reducing teen pregnancies
and STDs.
Study Design
 Abstinence education has received $87.5
million in funding each year.
 The Balanced Budget Act of 1997 authorized
a scientific evaluation of abstinence
education.
 Teens in four programs were compared to
control groups consisting of teens from the
same locations offered no services.
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All characteristics of the teens were the same
except program participation.
Results
 All graphs show no difference between
controls and program participants. Tables
show the following:
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Program teens were significantly more likely
than control teens to know that birth control
pills do not prevent STDs.
Program teens were significantly less likely
than control teens to know that condoms do
prevent STDs.
 Peer support is ineffective because social
groups change across adolescence.