Experiments Flashcards
independent variable
creates the conditions, this is manipulated
dependent variable
variable being measured - measured in same way for all conditions
extraneous variable
if not controlled can confound the results of the study - the researcher must try and control any variables that may interfere between the cause and effect relationship of the iv and dv
operationalisation
precisely defining a variable so it can be measured
lab experiment
conducted in a highly controlled environment which is artificial and set up for the study. Researcher directly manipulates the IV whilst keeping any other factors under control
field experiment
conducted in a natural setting where researcher manipulates the IV but in a naturally occurring environment
quasi experiment
researcher makes use of an existing Iv and therefore does not manipulate the IV, researcher can’t randomly assign participants to a condition
strength of lab
high levels of control means the researcher is confident that no extraneous variables have confounded the data
increases internal validity so C&E can be established between IV and DV
weakness of lab
artificial setting and tasks mean the study often bears little resemblance to real life
lacks ecological validity so findings can’t be generalized
strength of field
high ecological validity so likely to get behavior that resembles real life so findings can be generalized to real life situations
weakness of field
low levels of control so lots of extraneous variables so establishing C&E can be difficult reducing internal validity
strength of quasi
researcher can use an IV that would be unethical or not practical to manipulate
gather more insight which leads us to develop practical applications
weakness of quasi
Iv is naturally occurring so participants naturally belong to one condition or another
researcher can’t randomly assign conditions which may increase risk of individual differences
independent measures
participants are randomly assigned to one of the experimental conditions
repeated measures
participants take part in all experimental conditions
matched pairs/participants
researcher allocates participants to each group carefully to ensure that the groups match in terms of key characteristics
strength of independent
no risk of order effect
weakness of independent
high risk of individual differences
strength of repeated
no risk of individual differences
weakness of repeated
high risk of order effect
strength of matched pairs
no risk of order effect
weakness of matched pairs
very difficult to put in place
order effect
occur when participants experience multiple conditions and theor performance after the first condition is influenced by having done it before so they score higher through practice
counterbalancing
trials/tasks are presented in different orders to prevent order effects influencing the results
name the three types of extraneous variables
situational
participant
experimenter
situational variables
anything environmental that can effect participants behavoiur e.g noise, how crowded an area is
how to control situational variables
keep environment as similar as possible for all participants
participant variables
any differences between participants not accounted for in the IV like gender, age
how to control participant variables
having a large sample size (only minimises)
matched pairs
experimenter variables
researcher may unconsciously convey to participants how they should behave which is known as experimenter bias or researcher bias
can lead to demand characteristics
expectation effects
may occur when a researcher is deeply committed to achieving a particular outcome - may lead to self-fulfilling prophecy where a researcher subtly influences often without realizing the outcome like suggesting the group will do well
how to control experimenter variables
single blind procedure
double blind procedure
using placebo conditions
standardized instructions
single blind procedure
investigator prevents participant from knowing the aims of the study/ which condition they are in which reduces demand characteristics
double blind procedure
neither participants or researcher knows the true aims of the study/ condition allocation which reduces demand characteristics and prevents researcher bias
using placebo conditions
participants believe they are receiving something when they are not which controls demand characteristics
standardized instrucions
every participant receives all the same information so less possibility the researcher can communicate expectations. All participants receive same treatment and information
pilot study
small scale trial of a research design run before the real thing and often done to see if certain things work
by identifying potential problems with the research a psychologist can control possible ______ ______.
extraneous variables
