Experiments Flashcards
Lab exp?
A laboratory experiment is an experiment conducted under highly controlled conditions, where accurate measurements are possible.
Field exp?
A study that is conducted outside the laboratory in a “real-world” setting.
Quasi exp?
An experiment with a naturally occurring IV.
Control condition?
A condition that does not involve exposure to the treatment or intervention under study.
Independent variable?
A variable that is manipulated by a researcher to investigate whether it consequently brings a change in another variable.
Dependent variable?
The variable, which is measured and predicted to be dependent upon the IV
Extraneous variable?
Any variable that you’re not investigating that can potentially affect the outcomes of your research study.
Independent measures design?
An experimental design where different participants are used in each condition of the independent variable.
Repeated measures design?
An experimental design where the same participants take part in each condition of the experiment.
Matched groups design?
An experimental design where pairs of participants are matched in terms of key variables, such as age and IQ.
Controls?
A condition that does not involve exposure to the treatment or intervention under study.
Order effects?
The order of the conditions having an effect on the participants’ behaviour or/and outcome.
Counter balancing?
A technique used to deal with order effects when using a repeated measures design.
Advantages and disadvantages of repeated measures design?
ADV:
- Half the number of participants is needed to get the same amount of results as other designs
- Eliminates participant variables
DVNTG:
- Order effects
- Participants may eventually work out the aim/ purpose of the study and demand characteristics may arise.
Advantages and disadvantages of independent measures design?
ADV:
- No order effects
- Decreases the likelihood of demand characteristics
DVNTG:
- Results can be affected by participants variables.
- Twice as many participants needed to get the same sample of results as in other designs
Advantages and disadvantages of matched participant design?
ADV:
- Avoid order effects (participants only take part in one condition)
- Participants’ variables are reduced ( partic. are matched in conditions).
DVNTG:
- More complicated/time-consuming (pre-tests need to be carried out, to find matching characteristics)
- Not everything can be matched
- Twice as many participants are needed as in a repeated measures design, just to get the same amount of results
Advantages and disadvantages of Lab experiments?
ADV:
- Highly controlled
DVNTG:
- Low ecological validity
Advantages and disadvantages of Field experiments?
ADV:
- Increased ecological validity
DVNTG:
- Lack of control
- Ethical issues as sometimes participants may not know they are being assessed
Advantages and disadvantages of Quasi-experiments?
AD:
- Usually high levels of eco validity, due to the involvement of a naturally occurring IV.
- Can study the effects of variables that cannot be manipulated (weather).
DVNTG:
- cannot control extraneous variables
How can Participant variables be controlled?
- matched participant design or repeated measures.
- allocate participants to conditions randomly so that participant variables are more likely to be distributed evenly between conditions.
How can Situational variables be controlled (order effects) (environmental factors like times of day)?
- having different people in each condition (repeated, matched-participant design)
- if repeated measures design is used, then this should be counter-balanced. This is where the partic. are split into two groups: group 1 does condition A first then conditions B, while Group 2 does condition B first then A
- introduce controls on the experiment to ensure there are as few differences as possible between conditions (e.g. do them in the same room, at the same time, etc)
How can Demand characteristics be controlled?
- Single-blind procedure
Advantages and disadvantages of Self-selecting sample?
ADV:
- Consent
- Reduces researcher bias
DVNTG:
- more likely to end up with a smaller sample
- partic. may share similar personality traits (i.e confident to join in, eager to please) reducing population validity
Advantages and disadvantages of opportunity sampling?
ADV:
- often allows for a larger sample
- more cost-effective
DVNTG:
- researcher bias
- sample could be ethnocentric