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EXPERIMENTAL METHOD - Coggle Diagram
EXPERIMENTAL METHOD
Laboratory experiment
- An experiment carried out in a controlled environment
- All situational variables are controlled
- Participants are aware they are in an experiment, but might not know the aims
- Participants are randomly allocated to each condition (when appropriate) so that the experimenter has no control over which participants are in each condition, reducing bias
Strengths:
- One variable can be manipulated (IV)
- High level of control over EVs – high internal validity
- Reliably establish cause and effect (change in the DV due to the manipulation of the IV)
- Can be replicated (high external validity) as they are highly scientific
Weaknesses:
- May not represent behaviour in a real life setting: Lacks ecological validity and mundane realism (as they know they are being studied)
- Participants are likely to know that they are taking part in an experiment and may alter their behaviour due to demand characteristic (participant effects)
- Control causes artificial setting
Mundane realism
- Lab experiments lack mundane realism
- Mundane realism = how a study mirrors the real every world day
Field experiment
- An experiment carried out in the natural environment
- Some situational variables are controlled
- The IV is manipulated by the experimenter
- In most (but not all) – participants are unaware they are taking part, which reduces problems like demand characteristics
Example
- Hofling et al (1966) – pg 198
- IV – order over the phone from ‘Doctor smith’ to give a patient 20mg of Astroten
- DV – whether they gave the patient the drug or not
- 21 out of 22 nurses did as they were told
Strengths
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- Participants in natural environment, so findings likely to represent what you’d usually find in a real life setting: More ecological validity.
- Avoids demand characteristics (as they are not aware)
Weaknesses
- Confounding variables are more likely, so cause and effect may be less reliable – less internal validity
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- Participants may not know they are being studied = ethical issues