1. Experimental Research: Where cause meets effect
Lesson 12:
Research
Methods
(Variables and
Hypothesising)
Saturday, 28 January 2012

2. Lesson 11 BrainResearch Method
Exam Question
a) What information about the brain does positron
emission tomography (PET) provide? (1 mark)
b) When compared to computerised tomography (CT),
outline one advantage of using positron emission
tomography (PET). (1 mark)
c) What is the difference in the information provided by
magnetic resonance imaging (MRI) and functional
magnetic resonance imaging (fMRI)? (1 mark)
Saturday, 28 January 2012

3. Model Response:
a. What information about the brain does positron emission tomography (PET) provide? (1 mark)
Either of:
• the PET scan shows which areas of the brain are active while certain tasks are performed
• the PET scan gives information about brain functioning.
b. When compared to computerised tomography (CT), outline one advantage of using positron emission
tomography (PET). (1 mark)
Advantages of PET include:
• CT is static while PET shows the brain in action
• CT shows structural features and location of damage while PET shows functional areas
• PET is more sensitive than CT in detecting areas of brain damage
• unlike CT scans, PET scans are colour-coded, which aids interpretation
c. What is the difference in the information provided by magnetic resonance imaging (MRI) and functional
magnetic resonance imaging (fMRI)? (1 mark)
Differences include:
• fMRI uses a magnetic field to create a three dimensional image of the brain where any two dimensional slice can
be selected, and also displays brain activity on the screen
• MRI shows only the structure of the brain.
Saturday, 28 January 2012

4. Objectives: Lesson 12
• Outline the scientific method in
psychological research
• Identify variables including the
dependent, independent, extraneous
and confounding variables
• Construct a research and
operational hypothesis of a research
question
Saturday, 28 January 2012

5. Characteristics of an experiment
• IV is the variable selected and tested by the researcher to assess
effects on the DV (i.e participants responses)
• It is assumed that changes in the DV will result after exposure to the
IV.
• IV and potential unwanted variables (e.g extranious variables) are
controlled
• Use of random allocation of participants to different conditions
(groups) ensures uniform distributed participant characteristics
that can affect the DV.
Saturday, 28 January 2012

6. Variables
Independent variable – the variable that is changed by the
experimenter, interested in its effect. We want to see the effect of
the IV on the DV
Dependent Variable – measures the effect of the
IV, see if the IV has effected the DV
Saturday, 28 January 2012

7. Activity:
Research Question:
Does drinking alcohol effect driving?
Identify the IV and DV
Write a research hypothesis
Saturday, 28 January 2012

8. Experimental group and Control group
Experimental group: Participants
exposed to the treatment condition, i.e
the IV manipulation.
Control group: Participants not
exposed to the IV manipulation.
Saturday, 28 January 2012

9. The Research Hypothesis
Hypothesis – a testable prediction relating to the outcome of the
research being conducted, a prediction that one variable (IV) will
effect another variable (DV) in a certain way.
Saturday, 28 January 2012

10. Example
Research Question: Does smoking marijuana effect driving
performance?
Independent Variable - smoking marijuana
Dependent Variable - driving performance
It was hypothesised that participants who smoke marijuana
will perform worse on a driving test as compared to
participants who have not smoked marijuana
Saturday, 28 January 2012

11. The Operational Hypothesis
Variables that need to be operationalised
Smoking Marijuana
Driving Performance
The population – who we are testing
Operational Definitions
Smoking Marijuana – smoking one joint containing 500
milligrams of pure marijuana (not mixed with tobacco) 20
minutes before taking a driving test
Driving Performance -% score on VIC Roads, “Are you Road
Ready?”driving simulator
Population - Victorian drivers aged 18 – 25
Saturday, 28 January 2012

12. The Operational Hypothesis
It was hypothesised that Victorian drivers aged 18 – 25 who
have smoked marijuana (smoking one joint containing
500 milligrams of pure marijuana 20 minutes before
taking a driving test) will perform worse on a driving test
(obtain a lower % score on the VIC Roads “Are you Road
Ready?” driving simulator) compared to participants who
have not smoked marijuana.
Saturday, 28 January 2012

13. Activity:
Write a operational
hypothesis for your
research question.
Saturday, 28 January 2012

14. Extraneous and Confounding Variables
Extraneous Variable: Any variable, other than the IV, that can
cause a change in the DV and therefore affect the results of an
experiment in an unwanted way. An extraneous variable may
become a confounding variable.
Confounding variable: Any variable,
other than the IV, that is uncontrolled
and allowed to change together with
the IV, thereby having an unwanted
effect on the DV
Saturday, 28 January 2012

15. Watch Clip Below Summary
Saturday, 28 January 2012

16. Activity:
1)Identify one extraneous variable.
2)Identify an ethical breach in the
experiment.
Saturday, 28 January 2012

17. Revision
Do drivers who have more experience behind the wheel have less
accidents than less experienced drivers?
IV =
DV =
EV =
Research Hypothesis:
Operational Hypothesis:
Saturday, 28 January 2012