RED YELLOW PINK BLUE
BROWN GREEN BLACK
PURPLE WHITE ORANGE
GOLD BLACK YELLOW
BLACK YELLOW PURPLE
PINK RED BLACK BLACK
BLUE
SPAIN PORTUGAL ITALY
DENMARK SWEDEN
FRANCE ENGLAND
NETHERLANDS GERMANY
AMERICA MEXICO GREECE
JAPAN NORWAY
SCOTLAND WALES
BELGIUM FRANCE SPAIN
Independent and Dependent variables
• What is the IV for this experiment?
• What is the DV for this experiment?
• Exercise on page 12-13.
Controlling Variables
• Extraneous and Confounding Variables
• If the extraneous Vs are not controlled or can’t be
controlled then they may affect the DV.
• If this happens then these variables are described as
confounding variables. Confounding variables make
results less RELIABLE.
Extraneous Variables
• Excess noise/distraction – can be planned for.
• Intelligence of participants in each group – can be
controlled by putting people of equal IQ into each
group.
• Any others? E.g practice, fatigue, colour-blindness !!
• By controlling these, we can assume that if the test
times are lower for those in the ‘names of colours’
condition that this is the cause of a delay in
completing the task.
Ways of controlling confounding and extraneous
variables
• Counterbalancing = balancing out or swapping
the order that P’s do the conditions in
• This prevents the order/practice/fatigue effect
and helps to reduce demand characteristics
• How was this done in our experiment?
Ways of controlling confounding and extraneous
variables
• Standardisation = keeping all aspects of the experiment the
same for all P’s
• Randomisation = mixing up the material presented to P’s so
that it is in a random order
• It is also advisable to randomly allocate P’s to conditions to
prevent ‘bias’ i.e. making it equally likely that a P could
appear in either condition (chance)
• Relate these to our experiment!
More variable EXAMPLES
• PARTICIPANT VARIABLES: an unrepresentative sample, the
practice/order effect/intelligence etc.
• SITUATIONAL VARIABLES: where the situation is not held
constant and may adversely effect one group
• RESEARCHER BIAS: the treatment of P’s by the researcher
may not be consistent across groups
Demand Characteristics and Investigator Effects
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
INVESTIGATOR BIAS
Subjectivity
Expectations
Status
Non-verbal cues
PARTICIPANT BIAS
4 types of participant:
faithful/cooperative/negativistic/evaluatively apprehensive
Expectations
Demand characteristics
Hawthorn effect
WAYS OF REDUCING BIAS
Standardisation: instructions and procedure
Single blind method
Double blind method
•
Complete page 6 and 7
Plenary
•
•
•
•
•
•
•
•
•
Can you define …..
Independent variable
Dependent variable
Null Hypothesis
One tailed hypothesis
Two-tailed hypothesis
Extraneous variable
Confounding variable
What other variables are there?
Welcome to AS Psychology
•
•
•
•
•
•
Mrs Rust Ashford
Blog stcmpsy13.wordpress.com
textbooks
Objectives
Get to know each other
Think about how psychologists find out what
they know!
RED YELLOW PINK BLUE
BROWN GREEN BLACK
PURPLE WHITE ORANGE
GOLD BLACK YELLOW
BLACK YELLOW PURPLE
PINK RED BLACK BLACK
BLUE
SPAIN PORTUGAL ITALY
DENMARK SWEDEN
FRANCE ENGLAND
NETHERLANDS GERMANY
AMERICA MEXICO GREECE
JAPAN NORWAY
SCOTLAND WALES
BELGIUM FRANCE SPAIN
Independent and Dependent variables
• What is the IV for this experiment?
• What is the DV for this experiment?
• Complete Exercise on page 12-13
Controlling Variables
• Extraneous and Confounding Variables
• If the extraneous Vs are not controlled or can’t be
controlled then they may affect the DV.
• If this happens then these variables are described as
confounding variables. Confounding variables make
results less RELIABLE.
Extraneous Variables
• Excess noise/distraction – can be planned for.
• Intelligence of participants in each group – can be
controlled by putting people of equal IQ into each
group.
• Any others? E.g practice, fatigue, colour-blindness !!
• By controlling these, we can assume that if the test
times are lower for those in the ‘names of colours’
condition that this is the cause of a delay in
completing the task.
Ways of controlling confounding and extraneous
variables
• Counterbalancing = balancing out or swapping
the order that P’s do the conditions in
• This prevents the order/practice/fatigue effect
and helps to reduce demand characteristics
• How was this done in our experiment?
Ways of controlling confounding and extraneous
variables
• Standardisation = keeping all aspects of the experiment the
same for all P’s
• Randomisation = mixing up the material presented to P’s so
that it is in a random order
• It is also advisable to randomly allocate P’s to conditions to
prevent ‘bias’ i.e. making it equally likely that a P could
appear in either condition (chance)
• Relate these to our experiment!
More variable EXAMPLES
• PARTICIPANT VARIABLES: an unrepresentative sample, the
practice/order effect/intelligence etc.
• SITUATIONAL VARIABLES: where the situation is not held
constant and may adversely effect one group
• RESEARCHER BIAS: the treatment of P’s by the researcher
may not be consistent across groups
Demand Characteristics and Investigator Effects
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
INVESTIGATOR BIAS
Subjectivity
Expectations
Status
Non-verbal cues
PARTICIPANT BIAS
4 types of participant:
faithful/cooperative/negativistic/evaluatively apprehensive
Expectations
Demand characteristics
Hawthorn effect
WAYS OF REDUCING BIAS
Standardisation: instructions and procedure
Single blind method
Double blind method
•
Complete page 6 and 7
Plenary
•
•
•
•
•
•
•
•
•
Can you define …..
Independent variable
Dependent variable
Null Hypothesis
One tailed hypothesis
Two-tailed hypothesis
Extraneous variable
Confounding variable
What other variables are there?
OBSERVATION
• Used as a more valid measure of human
behaviour and experience
• They are more ethical (providing there is
informed consent, sometimes they might be
unethical!)
• Used when an experiment is not viable
• There is no direct manipulation of the IV
Observational exercise
• Work with a partner and take it in turns to observe
each other. One of you will be Person A and the
other will be Person B.
• Person A should have a difficult task to do (e.g.
answering a set of questions on something we have
studied in Psychology)
• Person B should have a boring task to do (e.g.
copying from a book)
• Each person should spend 5 minutes on their task,
while the other person observes them, noting down
any aspect of their partner’s behaviour
Observational Research
•
•
•
•
•
•
Types:
Natural – controlled (lab)
Participant – non participant
Covert – overt
Ways of recording observations
Time sampling- recording al aspects of behaviour
during a short time
• Event sampling – recording the no of times an
event occurs e.g smiling.
Reliability and Validity of Observations
• Reliability
• The issue is whether two
observers would come up with
the same observations. If they do
then you have inter-observer
reliability. To deal with this
Observers are trained to use a
coding system so that their
observations are consistent.
• Validity
• Observations are watching
people in a natural setting to
gain high ecological validity,
however they may lack
generalisability, also if the
coding system is flawed or if
the observer is biased, then
this may affect internal
validity. To deal with this
observations should take
place in several settings with
different observers.
– What data you want to
gather?
– Where you want to carry out
your observation?
– Who do you want to observe?
– What sampling method are
you going to use?
– How are you going to record
the data?
– Who is going to record the
data?
– How long are you going to
observe for?
– How many times are you
going to observe each group?
– What data you want to
gather?
– Where you want to carry out
your observation?
– Who do you want to observe?
– What sampling method are
you going to use?
– How are you going to record
the data?
– Who is going to record the
data?
– How long are you going to
observe for?
– How many times are you
going to observe each group?
•
•
•
•
•
•
•
Frequency / nominal / quantitative
In their playground at school.
Boys and girls – at least 20 of each
Volunteer and opportunity – the
local schools that agree to take
part.
With a clipboard for all playtimes in
a week at three different school.
Note down all behaviours i witness
and then put them into categories
afterwards!
me!
10 play sessions of 15 mins
Peer Assessment
• Is their study a naturalistic observation or a
laboratory observation? How do you know?
• Describe one way in which the reliability of their
observation of the play of boys’ and girls’ groups
could have been improved.
• Explain how any two factors might have affected
the validity of their study.
• Identify any ethical issues raised by their study.
• Identify and explain how these ethical issues
could be dealt with.
Measuring Reliability
Match the method of estimating reliability
to the description
Test-Retest
reliability
Split Half
Reliability
Inter-Rater
reliability
If the measure depends
upon interpretation of
behaviour, we can
compare the results
from two or more
raters.
Splitting a test into two
halves, and comparing
the scores in both
halves
The measure is
administered to the
same group of people
twice
If the results in the two
halves are similar, we can
assume the test is reliable
If the results on the two
tests are similar, we can
assume the test is reliable
If there is high agreement
between the raters, the
measure is reliable
Types of Validity
• Internal validity
– What happens inside the study, extraneous variables
controlled?
• External Validity
– How our results can be generalised beyond the study
– ecological validity, population validity/sampling
• Validity of psychological measures
– How well our methods of measurement actually
measure what we intend
Validity of psychological measures
• Content validity
– Does the method used actually seem to measure what you
intended?
– Get an independent expert to check
• Concurrent validity
– How well does the measure agree with existing measures?
– Check against an existing measure/test
• Construct validity
– Is the method actually measuring all parts of what we are
aiming to test?
– Check that test is appropriate to construct e.g are you asking
the right questions to test IQ?
Reliability
When assessing the reliability of a study, we
generally need to ask two questions
1. Can the study be replicated?
2. If so, will the results be consistent?
 High vs low reliability
Measuring Reliability
Match the method of estimating reliability
to the description (pg163)
Test-Retest
reliability
Split Half
Reliability
Inter-Rater
reliability
If the measure depends
upon interpretation of
behaviour, we can
compare the results
from two or more
raters.
Splitting a test into two
halves, and comparing
the scores in both
halves
The measure is
administered to the
same group of people
twice
If the results in the two
halves are similar, we can
assume the test is reliable
If the results on the two
tests are similar, we can
assume the test is reliable
If there is high agreement
between the raters, the
measure is reliable
Exam style questions – answer on
separate piece of paper. 15
minutes.
• A researcher is going to a primary school playground to observe
how aggression differs between boys and girls.
• (a) Outline one advantage and one disadvantage of using a
natural setting observation in this research. [3]
•
• (b) Identify one issue of reliability in this research and describe
how you could ensure reliability. [3]
•
• (c) Identify one issue of validity in this research and describe how
you could ensure validity. [3]
• P.S In the exam there will be 6 questions like this !
Quick Test
• Give two examples of situation variables that
might affect validity
• Give two examples of participant variables
• Give one issue which will affect the internal
validity of a study
• Give one issue which will affect the reliability
of a study.