Extraneous variable: Time of day How this could have affected the results: If some adults were approached in the morning and others in the afternoon, their ability to accurately recall and identify faces may have been affected by fatigue. Those approached later in the day when tired may have been less accurate in their identification than those approached earlier, thus confounding the results.

1. MONDAY 15th October 2012
Research Methods
L/O: to develop our understanding how psychological research is
carried out (AO3)
The findings can be said to
Good research should be: apply to others outside the
sample.
The experiment can be reliably
• Valid repeated.
• Generalisable If the experiment was done
again, the results would be the
• Reliable same or similar.
• Replicable
The experiment is measuring
what it claims to measure.

2. L/O: to develop our understanding how psychological research is
carried out (AO3)
Good research should be:
The experiment is measuring
• Valid what it claims to measure.
The findings can be said to
• Generalisable apply to others outside the
sample.
If the experiment was done
• Reliable again, the results would be the
same or similar.
• Replicable The experiment can be reliably
repeated.

3. L/O: to develop our understanding how psychological research is
carried out (AO3)
Laboratory experiment:
- Deliberately manipulates and controls the
variables
- Looks for causal relationships
e.g. 2 groups do the same task with one difference
any differences between the 2 groups
assumed to be due to that one difference.

4. L/O: to develop our understanding how psychological research is
carried out (AO3)
Laboratory experiment:
• It is the IV that varies.
• And the DV that changes.
Example: both groups drop a tennis ball
One group – wet ball (IV)
Other group – dry ball (IV)
Speed of drop (DV)

5. L/O: to develop our understanding how psychological research is
carried out (AO3)
REMEMBER:
Aim: to investigate the effects of music on memory.
Extraneous variables
Hypothesis: Music to be controlled affects (non-
need (rhythmic noise)
directional) memory (recall on a word list test).
for!
Less control = less
Conditions valid.
Experimental condition: the IV appears e.g. music
(wet ball)
Control condition: e.g. silence (dry ball).

6. L/O: to develop our understanding how psychological research is
carried out (AO3)
Standardised procedures
• Instructions: same for all participants.
• Why? Reduction of researcher bias.

7. L/O: to develop our understanding how psychological research is
carried out (AO3)
Experiments
Complete the table for Field and Natural Experiments using
text book pages 31-32.
Laboratory Field Natural
Features - Controlled -IV deliberately - No manipulation of
- IV deliberately manipulated variables
manipulated - In natural - In natural
- Looking for causal environment environment
relationship - Participants are - Participants are
- Standardised unaware of unaware of
procedures. experiment (lack of experiment (lack of
*Research design informed consent). informed consent).
applies to this method
only*
Strengths - replicable - Ecological validity. - High ecological
- Validity (unless real - Little to no validity.
life, behavioural) demand - Little to no
characteristics. demand

8. L/O: to develop our understanding how psychological research is
carried out (AO3)
Quasi- experiment
- Researcher cannot manipulate the IV
- E.g. effects of gender on intelligence.
IV: gender CANNOT CHANGE!
DV: intelligence
Laboratory?
Field?
Natural?

9. L/O: to develop our understanding how psychological research is
carried out (AO3)
Quick test! Total 10 marks in 10 minutes.
Explain what is meant by… (1 mark)
Explain one strength and one limitation of… (2+2 marks)
RIM
1) Repeated Measures Design You did this one in
2) Independent Groups Design the exam paper
3) Matched Pairs Design

10. L/O: to develop our understanding how psychological research is
carried out (AO3)
Repeated Measures Design
Counterbalancing
- A way to overcome order effects.
- E.g. half of the participants do no noise followed
by noise the next day (control condition
followed by experimental condition).
- Other half do the reverse (experimental then
control).
Result: order effects appear in both conditions
therefore balanced.

11. Dave, a middle-aged male researcher, approached an adult in a busy street. He asked
the adult for directions to the train station. He repeated this with 29 other adults.
Each of the 30 adults was then approached by a second researcher, called Sam, who
showed each of them 10 photographs of different middle-aged men, including a photo
of Dave. Sam asked the 30 adults to choose the photo of the person who had asked
them for directions to the train station.
Sam estimated the age of each of the adults and recorded whether each one had
correctly chosen the photo of Dave.
Suggest one reason why the researcher decided to use a field
experiment rather than a laboratory experiment (2 marks)
Identify one possible extraneous variable in this experiment. Explain
how this extraneous variable could have affected the results of this
experiment.
Extraneous variable……………………………………………………………………………….(1 mark)
How this could have affected the
results……………………………………………………………………………………………………(3 marks)

12. Suggest one reason why the researcher decided to use a field
experiment rather than a laboratory experiment (2 marks)
Participants are less likely to show demand characteristics
as in part 1 (Dave asking for directions) they are unaware
that they are taking part in an experiment.
Or
In real life situations people tend to respond genuinely so
the research findings are more likely to be generalisable
than if it was a laboratory experiment.
*when you have studied EWT you will likely mention that
this is important in an EWT experiment to be valid*

13. Identify one possible extraneous variable in this experiment.
Explain how this extraneous variable could have affected the
results of this experiment.
Extraneous variable………………………………………………………………1 mark)
How this could have affected the
results………………………………………………………..(3 marks)
e.g. how the researcher asked for directions, time of day, gender / eye
sight of participants.
(Anything other than IV for 1 mark)