experiments Flashcards
1
Q
what is a lab experiment?
A
An experiment that takes place in a controlled artificial environment within which the researcher manipulates the IV and records the effect on the DV, whilst controlling extraneous variables
2
Q
what is a strength of lab experiments?
A
- high control over extraneous variables, meaning that the researcher can ensure any effect on the DV is likely to be the result of the manipulation of the independent variable
- thus, we can be more certain about demonstrating a cause and effect relationship between the IV and DV, increasing the internal validity of
3
Q
another strength of lab experiments
A
- replication is more possible than in other experiments because of the high level of control and standardised procedures
- vital to check whether results are internally valid or just a one off
4
Q
Limitation of lab experiments
A
- lack ecological validity due to artificial lab environment and not being like everyday life, tasks don’t resemble real life
- results can’t always be generalised beyond lab setting
5
Q
limitation of lab experiments
A
- participants usually aware they are being tested in a lab experiment, may cause participants to show demand characteristics
- reduce the internal validity of the findings , can’t establish cause and effect relationship
6
Q
What is a field experiment?
A
- take place in natural setting within which the researcher manipulates the IV and records the effect on the DV. Usually natural environment of the participants
7
Q
Strength of field experiments
A
- high ecological validity because environment is more natural and less likely to be controlled
- makes findings generalisable to real-life behaviour
8
Q
Limitation of field experiments
A
- lack control over extraneous variables
- difficult to establish cause and effect relationship, reducing the internal validity
9
Q
Another strength of field experiments
A
- unaware they are taking part in study, less likely to show demand characteristics.
- produce behaviour that is more authentic and internally valid, increasing the internal validity of the findings
10
Q
Another limitation of field experiments
A
- if participants unaware they are being studied, cannot consent
- unable to withdraw
- damages the reputation of psychology
11
Q
What is a quasi experiment?
A
The IV has not been manipulated by anyone - variables simply exist and are naturally occurring e.g. age, gender
12
Q
Strength of quasi experiment
A
- carried out under controlled conditions
- ensure cause and effect relationship, increases internal validity
13
Q
Another strength of quasi experiments
A
- comparisons can be made between people, as the IV is a difference between people
- comparison makes research useful
14
Q
Weakness of quasi experiment
A
- cannot randomly allocate participants to conditions and therefore extraneous variables such as participants variables will exist
- reduced the internal validity of the findings, can’t establish cause and effect relationship
15
Q
What is a natural experiment?
A
- when the researcher takes advantage of pre-existing independent variable
- variable would have changed even if the experimenter wasn’t interested
16
Q
Strength of natural experiment
A
- provide opportunities for research that may not otherwise be undertaken for practical or ethical reasons
17
Q
Another strength of natural experiments
A
- higher ecological validity because they involve the study of real-life issues and problems as they happen
18
Q
Weakness of natural experiment
A
- naturally occurring event occurs rarely, reducing opportunities for research, may limit scope for generalising the findings
19
Q
Weakness of natural experiment
A
- participants not randomly allocated to conditions
- reduced internal validity
20
Q
What is an aim?
A
A general statement of what the researcher intends to investigate the purpose of the study “to investigate”
21
Q
What is an independent variable?
A
Manipulates purposely by the experimenter, different conditions of the study
22
Q
What is a dependent variable?
A
Measured - data collected from participants
23
Q
What does operationalising variables mean?
A
The precise definition of what is being measured in the research (IV, out of, time, DV)
24
Q
What is a hypothesis?
A
A clear, precise testable statement that includes operationalised variables, prediction
25
What is a directional hypothesis?
States the direction of the difference or relationship (e.g. more or less)
26
What is a non-directional hypothesis?
Doesn’t state the direction of the results e.g. difference
27
What is a null hypothesis?
States that there will be no difference
28
How do psychologists decide which hypothesis to use?
- use directional if findings of previous studies suggest a certain direction
- use non-directional if no previous research
29
What is an extraneous variable?
Any variable other than the independent variable, that may have an effect on the dependent variable if not controlled.they are essentially nuisance variables that do not vary systematically with the IV.
- reduce the internal validity of a study
30
What is a situational extraneous variable and how can they be controlled?
- aspects of an individuals environment or the task set that may affect participants behaviour in the study e.g. lighting, temperature, noise
- controlled : have carefully standardised procedures and test conditions
31
What is a participant extraneous variable?
- characteristics of individual participants such as their age, sex, motivation that might influence the study’s outcome
Controlled = more difficult to control, can be partially overcome using matched pairs design
32
What is investigator effects and how can they be controlled?
- any effect of the investigators behaviour, conscious or unconscious on the research outcome (DV) such as design of study, interaction with participants, clothing
Controlled = each participants experience same conditions, same experimenter should be used, interactions should be standardised
33
What are demand characteristics?
-any cue from the researcher or from the research situation that may be interpreted by participants as revealing the investigations purpose, may change behaviour
34
What is standardisation?
Using exactly the same formal procedures and instructions for all participants in research
35
What is an independent groups design?
When two separate groups of participants experience different conditions of the experiment. If there are two conditions of the independent variable, only experience one condition
36
Strength of independent groups design?
- order effects aren’t a problem, participants only take part in one condition, less likely to show practice or boredom effects
- increases internal validity of the findings
37
Another strength of independent groups design
- take part in one condition, less likely to guess aims of study and show demand characteristics
- increases internal validity of findings
38
Weakness of independent groups design
- different participants are used in each condition which means that participant variables will affect the results
- act as extraneous variables, reducing the internal validity
39
Another weakness of independent groups design
- les economical as each participant contributes single result, require twice as many participants as would be needed to produce equivalent data to repeated measures design
- more time-consuming and costly
40
What is a repeated measures design?
- all participants take part in all conditions of the experiment
- sets of data will be compared to see if there was a difference
41
Strength of repeated measures design?
- participant variables or individual differences are controlled, as take part in both conditions
- increases internal validity
42
Weakness of repeated measures design
- order effects are a problem, take part in all conditions
- could cause fatigue or boredom
- deterioration on second performance or improved due to practice
- reduced internal validity
- counterbalancing
43
Counterbalancing
Reduces order effects, as half participants take part in condition A followed by condition B, other half complete condition B followed by condition A
44
Another strength of repeated measures design
- more economical as each participant contributes to both conditions, half as many participants needed
- less time-consuming and costly
45
Another weakness of repeated measures design
- as they take part in both conditions, more likely to show demand characteristics and guess the aim of the study
- reduces internal validity of the study
46
What is matched pairs design?
Pairs of participants are first matched on some relevant variables that may affect the DV
- one member assigned to condition A other assigned to condition B. Take part in one condition
47
Strength of matched pairs design
- participant variables or individual differences controlled as participants matched on similar characteristics
- increases internal validity
48
Another strength of matched pairs design
- order effects aren’t a problem, take part in one condition
- increases the internal validity
49
weakness of matched pairs design
- although there is some attempt to reduce participant variables, participants can never be matched exactly
- still important differences between them may affect DV
- reduces the internal validity of the results
50
Another weakness of matched pairs design
- it is less economical as twice as many participants needed, single result only
- more time-consuming and costly
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