experiments + experimental designs Flashcards
what are experimental methods? what are the 4 main experimental methods
4 = lab, field, natural and quasi
- they are methods that involves the manipulation of an independent variables to measure the effect on the dependent variable
what are lab experiments
- take part in a controlled condition
- they manipulate the IV and measures the DV
- participants are aware of taking part in a experiement
strengths within a lab experiment
- highly controlled
- has high internal validity
- can easily replicate to back up results
- has high control over extraneous variables
weaknesses within lab experiments
- low ecological validity
- use of artificial tasks, so the findings can’t be generalised to real life situations/ environments
- prone to demand characteristics
what are field experiments
- done in an everyday setting
- manipulates the IV and measures the DV
- participants are often not aware of being participants in an experiment
strengths within field experiments
- high ecological validity
- researchers can easily generalise findings
- has fewer demand characteristics, which increase the internal validity of field experiments
weaknesses within field experiments
- has low internal validity
- unable to fully determine the cause and effect
- they can raise major ethical issues
- can be unethical as doesn’t gather informed consent from the participants
what are natural experiments
- every day setting/ controlled
- iv is naturally occurring, and measures the DV
- conducted when its not possible, for ethical and practical reasons to manipulate an IV
strengths within natural experiments
- tend to have high ecological validity
- more generalisable beyond the research setting, resulting in high external validity
- reductions of demand characteristics and investigator effects
weaknesses within natural experiments
- they can be difficult to replicate
- they are often low in internal validity
what are quasi experiments
- controlled/everyday settings
- IV is a difference between people, and measures the DV
strengths within quasi experiments
- enables comparisons between different types of people
- carried through controlled conditions
weaknesses within quasi experiments
- can not random allocate to research conditions to remove the issue of bias
what are experimental designs
refers to a way in which participants are used in experiments
what are the 3 different types of experiments designs
independent groups design, repeated measures design and matched pairs design
what are independent group measures
where each participant experiences only one condition
strengths for an independent group measures
- has order effects
- increases external validity because more participants are used
weaknesses for independent group measures
- participant variables, differences between the people may affect the results, leading towards errors
how to deal with the weakness within independent group design
randomly allocate participants to conditions which distribute participants variables evenly
what are repeated measures design
where each participant experiences all the conditions
strengths within repeated measures design
- participant variables, same people do the tests in both conditions
- number of participants, need to get the same amount of data
