types of experiment Flashcards
what is an experimental method
the method used to carry out an experiment
what are the 4 types of experiments
→ lab
→ field
→ quasi
→ natural
what is a lab experiment
an experiment that takes places in a controlled environment within which the research manipulates the IV and records the effect on the DV
what do you manipulate in a lab experiment
the IV
what do you record in a lab experiment
the DV
where does a lab experiment take place
in a controlled environment
what are the advantages of a lab experiment
→ high internal validity
→ high levels of control over extraneous variables
→ high replicability as it uses operationalised variables
what are the cons of a lab experiment
→ may lack generalalibility and mundane realism - artificial tasks and environments used
→ reduces ecological validity
→ gives rise to demand characteristics
what is a field experiment
an experiment that takes place in a natural setting within which the researcher manipulates the IV and records the effect of the DV
what do you manipulate in a field experiment
the IV
what do you record in a field experiment
the DV
where does a field experiment take place
in a natural setting
what are the pros of a field experiment
→ higher mundane realism
→ high ecological validity - tasks and environment are natural
→ lower chance of demand characteristics
what is a natural experiment
an experiment where the change in the IV is not brought about by the research (would have occurred anyway) and the change in the DV is recorded
what are the cons of a field experiments
→ low internal validity - less control over extraneous variables
→ harder to replicate findings
→ problem with ethics as pps may not consent to being in the study if they are using a covert observation
what is recorded in a natural experiment
the DV
how is the change in the IV brought about in a natural experiment
it is naturally occurring → not manipulated by the experimenter
what are the pros of a natural experiment
→ provides a chance to collect research on things that would not be ethical to conduct in a field or lab experiment
→ for example: the Romanian orphans research by Rutter
→ high ecological validity - no artificial tasks or environment
what are the cons of a natural experiment
→ very rare event - lack generalibility
→ low internal validity - cannot randomly allocate pps to each experimental condition
→ harder to establish cause and effect due to confounding variables
what is a quasi experiment
an ‘experiment’ where the IV is a pre-determined variable such as age or gender and its effect on the DV is recorded
→ the researcher cannot manipulate the IV directly as it is based upon existing differences between people
what are some pros of a quasi experiment
→ allows us to measure the effect of a pre-determined variable in different settings or tasks
→ high ecological validity
what are some cons of a quasi experiment
→ low internal validity - cannot randomly allocate pp to each experimental condition
→ research cannot directly control the IV - difficult to control extraneous variables and prevent them from becoming confounding variables → cause and effect cannot be established
what experimental method would this be?
Dave a middle aged male researcher approached an adult in a busy street. he asked the adult for directions to the train station. He repeated this with 29 other adults. Each of the 30 adults was then approached by a second researcher, Sam, who showed each of them 10 photographs of different middle-aged men, including a photo of Dave. Sam asked the 30 adults to chose the photograph of the person who had asked them for directions to the station. Sam estimated the age of each of the 30 adults and recorded whether each one had correctly chosen the photograph of Dave
field experiment
what experimental method is this?
A research investigated whether people with obsessive compulsive disorder (OCD) are more aware of their own heartbeat than people who do not have OCD. A matched pairs design was used. This involved 10 people with OCD and 10 people without OCD. The researcher asked each pp to estimate how fast his or her heart was beating (in beats per minute) and this was compared to his or her actual heartbeat. it was found that people with OCD were more accurate at estimating their own heartbeat then people without OCD
quasi experiment
