experiments Flashcards
define a field experiment
- an experiment that takes place in a natural setting
- experimenter manipulates the IV and measures the DV
advantages of a field experiment
+ behaviour is more likely to reflect real life because of its natural setting = higher ecological validity than lab
+ less likelihood of demand characteristics as ppts don’t know they’re being studied
disadvantages of a field experiment
- less control over extraneous variables = biased results = which makes it difficult to replicate
- ethical issues = ppts cannot consent + invasion of privacy
define quasi-experiments
the independent variable can not be randomly assigned because it is an innate difference of the participants themselves.
- A memory task with a group of clinically depressed participants compared to a control group of non-depressed participants
advantages of a quasi-experiments
+ IV naturally occurring within the individual it may be more reflective to that individual
+ allow researchers to investigate variables that would be unethical to manipulate
disadvantages of a quasi-experiment
- hard to replicate = lack internal and external reliability
- control over extraneous variables is difficult = researcher is not manipulating the IV = less sure that it cause an effect on the DV
define a lab experiment
- takes place in a controlled environment = experimenter manipulates the IV and measures the DV
- often have a control group and experimental group
2 ways of taking a lab experiment:
1. Standardized instructions- The instructions given to each participant are kept identical – to help prevent experimenter bias.
2. Standardised procedures- In every step of the research all the participants are treated in exactly the same way and so all have the same experience.
advantages of a lab experiment
+ It is easier to replicate = because a standardized procedure is used.
+ They allow for precise control of extraneous and independent variables. This allows a cause-and-effect relationship to be established.
disadvantages of a lab experiment
- artificiality of the setting = unnatural behavior that does not reflect real life, i.e. low ecological validity.
- would not be possible to generalize the findings to a real-life setting.
- Demand characteristics or experimenter effects may bias the results and become confounding variables.
define a natural experiment
These are conducted in the day (i.e. real life) environment of the participants,
- experimenter has no control over the IV as it occurs naturally in real life
advantages of a natural experiment
- Behavior is more likely to reflect real life because of its natural setting, i.e. very high ecological validity.
- less likelihood of demand characteristics affecting the results, as participants may not know they are being studied.
- Can be used in situations in which it would be ethically unacceptable to manipulate the independent variable, e.g. researching stress.
disadvantages of a natural experiment
- may be more expensive and time-consuming than lab experiments
- no control over extraneous variables that might bias the results = This makes it difficult for another researcher to replicate the study in exactly the same way.
