Research Methods - Experimental Design Flashcards
What is meant by experimental design?
Refers to how many participants are organised across the conditions.
What are experimental designs often confused with?
Research methods such as field, lab or natural.
What is an independent groups design?
In an independent groups design, each participant takes part in one condition only and they are selected for one group only. A researcher recruits a group of participants and they divide them equally into two. One group does condition 1 and the other does condition 2.
What are the strengths of an independent groups design?
Order effects are reduced as the participants only take part in one condition. Therefore they don’t get to practice the task or become fatigued.
Demand characteristics reduced as the participants only take part in the one condition.
What are the weaknesses of an independent groups design?
Participant extraneous variables between the groups lowering the internal validity of the study.
Less economical.
How can the problem of participant variables be combatted in an independent groups design?
Use random allocation
How are participants randomly allocated in an independent groups design?
Use a random number generator.
The lottery method - draw names out of a hat; the first 10 names in condition A and the second 10 in condition B.
What is a repeated measures design?
Each participant takes part in both conditions; they’re selected for both groups.
A researcher recruits a number of participants, they would all complete condition 1 e.g morning learning. Then they’d all complete condition 2 e.g afternoon learning.
What are the strengths of a repeated measures design?
Participants extraneous variables are controlled for but they’re never fully eliminated. E.g age variation.
Less participants needed as they appear in both conditions.
What are the weaknesses of a repeated measures design?
Order effects – an extraneous variable where the order in which conditions of the experiment effects the results e.g practice effects or fatigue effects.
Demand characteristics - a cue that makes p’s unconsciously aware of the aims of a study or helps p’s work out what the researcher wants to find and this causes them to change their behaviour.
How can you reduce the impact of order effects in a repeated measures design?
Counterbalancing - using A-B B-A design
What is a matched pairs design?
Each participant takes part in one condition (group) only. The participants are matched on variables considered relevant. E.g age, sex, IQ.
What are the strengths of a matched pairs design?
Single condition - order effects and demand characteristics reduced.
Participant extraneous variables are reduced.
What are the weaknesses of a matched pairs design?
Decrease in participant variables but participants can’t be truly matched.
Time consuming
Expensive
(Therefore it’s less economical)
