experimental ecology issues in psychology

1. Developmental Research
Methods
Topic 10: Experimental Ecology?
10/1/2014 CEDP 321/322 Ryan Sain, Ph.D. 1

2. Experimental Ecology
 The experiment is an interaction
between the experimenter, subjects and
environment
 Laboratory observation vs. external
observation
◦ Mothers and play
 Ecological validity
◦ How much does the context influence the
findings?

3. Experiment
er effects
 Bias in data
collection
◦ Maskelyne
and
Kinnenbrook
 This is a case
of the
PERSONAL
EQUATION
 Operational
definitions help
this
 Multiple
observers
 Interrater
reliability

4. Bias in data errors
• Favor own hypothesis
• Morton – intelligence across races
• Selection bias
• Did not know he was doing this
• Sometimes its not so innocuous
• Burt - manipulation of data to support his theory.
(intelligence is a result of genetic factors)

5. Biased interactions
 Experimenters can treat various
subjects differently
◦ Attractive, male, female, etc.
 Use scripts
◦ We also bias people by hinting at what the
goals of our research are.
 Subjects will then try to change their behavior
to match or not match our goals.

6. Reducing bias
 Use multiple experimenters
 Blinding
◦ Blind the subject
◦ Blind the experimenter or both

7. Subject factors
 Problems with interpreting results
come from subjects too.
 These are huge issues and cloud the
experiment in the forms of threats to
validity.

8. Hawthorne effect
 A thing observed
changes
 Ladies working at a
production plant
◦ Increased
productivity in
general – even
when they should
not have.
◦ They were reacting
to being part of the
study and felt
special as a result –
and increased
productivity.

9. Placebo (expectancy)
 Just the act of taking something may
cause you to change on whatever
factor it is.
◦ Headaches, etc.
 You can control this by taking
measurements BEFORE you start the
placebo condition to see if they
change in the placebo condition as
well.
◦ Mixed design
 You can also control for this through
blinding.

10. Demand Characteristics
 Participants response is influenced by
the experimental setting by
themselves.
 They have an idea about how to
behave in a given situation
◦ They then match their behavior to that
idea.
◦ Alcohol, marijuana, etc.
 Deception helps control for these.
 Distractors help control for these.

11. Cultural bias
 Our bias may be the culture itself
◦ African Americans and psychotherapy
 Rules for including minorities and
women in research

12. Paradigms
 Changing the way we see the world
allows us to ask new questions about
it.
 New technologies
 New discoveries.