Transcript Psy Basic Experimentation Text PP 16-17

The Scientific Method
 Step 1: A theory is a potential
explanation that attempts to predict
behavior/events; a “hunch”
“I think students will perform better on their
exams if they can use notes.”
 Step 2: A hypothesis is a specifically
written testable prediction about a
relationship between two variables that
allows us to accept/reject the theory
“Students who use notes during exams will attain
a higher average score than those who don’t.”
 Step 3: An experiment conducts the study
to either confirm or disprove the hypothesis.
 One section of Psych students will use notes. Then
compare their scores to a section that doesn’t.
Experimental Purpose
• Experiments prove cause and effect!
– Descriptive studies (case studies, surveys, correlations, etc.) are
great for gathering data, but they can’t show cause and effect; only
experiments can!
• Every term/concept/idea we learn this year has
been proven through experimentation in the past.
• Example: Proving social facilitation (performing
better in the presence of others)
– Scientists put cyclists into two groups.
– The first group raced solo against
the clock.
– The second group raced against
each other.
– The second group, on average,
had faster race times.
Experimental Purpose
• The purpose of an experiment is to see how
changing one variable affects another variable.
– How does a new type of drug affect the
remission of cancer in patients?
• The hypothesis is your educated guess as to
what kind of relationship you expect to find.
– Patients who try the new drug will experience
greater cancer remission than those who don’t..
– Note: It’s OK if your hypothesis ends up being
wrong. You’re still learning something either way.
Experimental Terminology
• The variable the experimenters
change (manipulate) is known
as the independent variable (IV).
– In any type of drug study, the drug itself is
usually the independent variable.
• An experiment must only have one IV!
Experimental Terminology
• The variable the experimenters measure (based
on the change from the IV) is known as the
dependent variable (DV).
– It has this name because it is
DEPENDENT on the independent
variable change. If the IV’s change
had an impact, the DV should have
varied in some way.
– In a drug study, the effect of the
drug is the dependent variable.
Experimental Terminology
• Any other variables that could
possibly be affecting the results
of the experiment besides the
independent variable are known
as confounding variables.
– THESE ARE BAD!
– A well conducted experiment should
eliminate all confounding variables.
– In a drug study, confounding variables
would be anything else that helps the
patients get better.
Experimental Terminology
• The group that
• The group that does not
receives the treatment receive the treatment is
is the experimental
the control group.
group.
– This is the comparison group;
– If it’s a drug study, the
experimental group is the
group that receives the drug.
we compare their data to the
experimental group(s).
– In a drug study, it would be the
group not receiving the drug (or
getting a placebo).
Sample Experiments
• Label the experimental
terminology appropriately:
Independent Variable:
Type of music
Dependent Variable:
IQ test score
Confounding Variable(s):
The Mozart Effect suggests that children
under 3 who listen to classical music have
enhanced brain development. To test this,
one group of 2-year-olds is exposed to
classical music for a year, another group is
exposed to punk rock, a third listens to
techno, and a fourth group listens to no
music at all. After the year is over, all the
children take an IQ test.
Natural intelligence, previous
music exposure, parenting, etc.
Experimental Group(s):
EG1: Classical group, EG2: Punk
rock group, EG3: Techno group
Control Group:
No music group
Sample Experiments
• Label the experimental
terminology appropriately:
Independent Variable:
Type of monster
Dependent Variable:
Max running speed
Confounding Variable(s):
Dr. Evil would like to learn how being chased
by various predators affects the running
speed of humans. Various groups of people
are chased by a ghost, a bear, Bigfoot, a
Tyrannosaurus Rex, or a Yeti; one group is
not chased at all. The average max speed of
the runners is measured during the chase.
Age of runner, body type of
runner, footwear, clothes, etc.
Experimental Group(s):
EG1: Ghost group, EG2: Bear group, EG3:
Bigfoot group, EG4: T-Rex group, EG5:
Yeti group
Control Group:
No monster group
Sample Experiments
• Label the experimental
terminology appropriately:
Independent Variable:
Exercise type
Dependent Variable:
Competition performance
Confounding Variable(s):
Body type, competition exercise
type, previous exercise, etc.
The conductor of a research study
hypothesizes that performing squats builds
more muscle than performing deadlifts. For
six weeks, one group performs squats, one
group performs deadlifts, and then both
groups compete in a weightlifting
competition.
Experimental Group(s):
Squat group (in cases like this, put
the hypothesized “achiever” here)
Control Group:
Deadlift group
Experimental Ethics
• Conducting a psychological
experiment today requires that
researchers follow established
ethical guidelines
– Potential experiments must be written up
and submitted before they can be
conducted; an ethics board needs to
verify they are safe to perform
• These guidelines are
established by psychology’s
governing body, the American
Psychological Association
(APA)
– First published in 1953 after WW2 era
Experimental Ethics
1. Must not harm participants
2. Must not break any laws
3. Must obtain informed consent before
and debrief participants after
4. Deception is OK as long as participants
are informed of the deception after
the experiment is concluded
5. Must keep individual results
confidential, unless permission is
granted by participants or a participant
reveals plans to harm self or someone
else
6. Harm to animals is permissible if
it is for the greater human good, there
is no alternative, and the benefits
outweigh the harm