experiments and design Flashcards
Lab experiments Location? What is manipulated? Strength?- link to relaibility Weakness?
Lab experiments occur in controlled environments- the IV is manipulated and its effects on the DV are recorded
Strengths- As the procedure is highly controlled there is a lack of extraneous variables meaning that the researchers can be certain that any behaviours are due to the IV being manipulated
As the procedure is standardised, the study has high replicability
Weakness- As the experiment occurs in a high controlled setting, the study lacks ecological validity as the artificial environment is not normal for participants to experience and therefore their behaviour could be different compared to how they would behave in reality.
Field experiments Location? What is manipulated Strengths what type of validity? Weakness?
Field experiments occur in natural settings
The IV is manipulated
Strengths- As the procedure occurs in a natural setting it has high ecological validity
Weakness- However conducting an experiment in a natural setting means that there is a lack of control over extranoues variables therefore mking it more difficult to establish if the behaviour observed was due to the IV being manipulated or because of outside factors.
Quasi experiment
What is manpulated?
Strengths?
Weaknesses?
In quasi experiments the IV is naturally occurring therefore it is not manipulated by the researcher.
Strengths- Qausi experiments allow researchers to study the effects of factors which may raise practical and ethical issues such as comparing people with mental illness
Weaknesses- As the Iv is naturally occurring there is no controls over extraneous variables. For example participant variables as the participants are in different age groups, different levels of education etc
Repeated measures design
definition?
Advantages? - What extraneous variable is prevented? time?
Disadvantages?- what extraneous variable is likely? what does this mean for the behaviour of partiipants?
In repeated measures design the same participants are used in each condition?
Advantages As the same participants are used in each condition, the results are not impacted by participants variable as the level of ability etc is consistent
Additionally, having the same participants for every condition means that researchers need to spend less time recruiting participants
Disadvantages- Completing both conditions means that results could be impacted by order effects as participants may get better at the procedure or become tired and not focus as well on the task.
Independent measures design
definition?
Advantages? What extraneous variables are prevented? what are participants less likely to figure out and do?
Disadvantages? what extraneous variables is likely to occur? number of participants?
In an independent measures design different participants are used for each condition
Advantage- Different participants in each condition means that results are not going to be impacted by order effects
Only completing one condition may reduce the likelihood of demand characteristics, as the participants figure out the hypothesis if the experiment and change their behaviour.
Disadvantages- Different participants in each condition means that participant variables could impact results as participants may have different characteristics
Twice as many participants are needed as different participants are being allocated to each condition
Matched participants design
How are participants allocated?
Advantages? What extraneous variables are avoided? Why?
Disadvantage?
Participants are matched on key characteristics a member of each pair is allocated to each condition
Advantage- Matching participants on key characteristics reduces the likelihood of participant variables impacting results
As each participant is only doing on condition there are no order effects
Disadvantages- It is time consuming to match participants
