experiments Flashcards
what is an experiment and what are the three types
an experiment is used to test a hypothesis- we have a variable that is being tested across the conditions, it can be either naturally occurring or directly manipulated. everything else is kept the same. if groups think/ behave differently then you know it is the thing you have changed that caused the different result as everything else was standardised
the three types are: lab, field and quasi
what is the IV and what is the DV
the independent variable (IV) is the one we manipulate and change across conditions to see how it affects the dependent variable (DV), which is the one we measure
what are extraneous variables
extraneous variables are extra variables which may affect the DV. they need to be standardised so they don’t affect the DV as this would invalidate the experiment e.g. ensuring all participants ate breakfast before completing the experiment so hunger levels do not affect performance
what are cofounding variables
cofounding variables are variables we cant or didn’t control. they reduce the validity of the experiment meaning we may not be measuring what we need to be measuring.
what does it mean to operationalise
operationalising is stating clearly how a variable will be manipulated or measured e.g you cant say someone is smarter than someone else but you can say someone has a higher IQ than someone else
what are overall strengths of experiments
experiments are the only way to establish cause and effect in psychology, making it a science
they are all highly standardised to ensure cause and effect to be established
what are overall weaknesses of experiments
experiments are difficult to make generalisable to the whole wider population as they can only test a relatively smaller range of people
experiments are open to human error which could make results less reliable as we may not be testing what we want to be testing
what is a lab experiment
lab experiments are conducted in artificial environments. a lab is any controlled environment where the researcher can keep the conditions the same across all conditions for all participants. we are still manipulating one variable (IV) and measuring another (DV)
evaluate the use of lab experiments
+ experimenters are in full control of the environment which reduces extraneous variables
+ easier to replicate the study, making it more reliable
+its easy to establish cause and effect
-lacks ecological validity
-higher chance of demand characteristics
-chances for experimenter bias
what is a field experiment
field experiments are conducted in the participants natural environment in real life, still manipulating the IV and measuring the DV
evaluate the use of field experiments
+ reduced demand characteristics
+ high in ecological validity
-difficult to replicate
-harder to control extraneous variables
-harder to establish cause and effect
-chances for experimenter bias
what is a quasi experiment
quasi experiments have a naturally occurring IV, which cannot be manipulated
can be either a lab or field ex[eriment
evaluate the use of quasi experiments
+allows us to look at variables it would be impossible or unethical to look at otherwise
-sample can be bias as the researcher has little control over the IV
can be carried out in either a field or lab so has the same strengths/weaknesses of those
describe the three experimental designs
repeated measures: using all participants in all conditions
independent measures: using different participants in each condition of the IV
matched pairs: participants are matched for variables that could affect results, then each participant only takes part in one condition of the IV
evaluate the repeated measures design
+ reduction in individual differences since participants see all conditions so their results can be compared to establish cause and effect
- open to order effects as the participant can become practiced at the task after seeing the first condition which may improve their performance of the second condition
- the aim is easier to guess since the participants can see what has changed across conditions, this could increase the chance of demand characteristics
