experiments Flashcards
define independent variable
what the researcher wants to compare/manipulate/change
define dependent variable
what the researcher measures
define extraneous variables
factors which may influence your DV and aren’t your IV, but that can be controlled to minimise their effects
define confounding variables
factors which may influence your DV and aren’t your IV but are outside your control
what is a laboratory experiment?
conducted in a controlled/artificial environment with a manipulated IV
what are the strengths of a lab experiment?
- high level of control, increasing replicability
- easier to establish causal relationship as we are manipulating the IV
- most scientific type of experiment and often uses objective equipment
what are the weaknesses of lab experiments?
- increased chance of demand characteristics
- low in ecological validity due to high level of control
what is a field experiment?
- manipulated IV
- environment is where you would expect to see that behaviour occur or in a natural environment
what are the strengths and weaknesses of field experiments?
STRENGTHS:
- higher ecological validity
- easier to establish causal relationship as we are manipulating the IV
WEAKNESSES:
- reduced level of control
- lower replicability
- less scientific due to lower levels of control
what is a quasi experiment?
- naturally occuring IV
- can be conducted in either controlled or naturally occuring environments
what are the strengths and weaknesses of quasi experiments?
STRENGTHS:
- allows us to investigate variables it would be impossible/unethical to investigate otherwise
- can be carried out in a lab or in the field so may have the same strengths as those types
WEAKNESSES:
- difficult to establish causal relationships because the IV is not controlled/manipulated
- sampling bias as the researchers cannot control who takes part in each condition
what is an independent measures design?
where different participants take part in each condition
what are the strengths and weaknesses of an independent measures design?
STRENGTHS:
- no chance of order effects
- reduced risk of demand characteristics (les likely to guess aim)
WEAKNESSES:
- any difference between conditions may be down to individual differences
- need to recruit a larger number of participants
what is a repeated measures design?
the same participants take part in each condition
what are the strengths and weaknesses of a repeated measures design?
STRENGTHS:
- only have to recruit half as many participants
- no individual differences (using the same people)
WEAKNESSES:
- possible order effects
- higher risk of demand characteristics
what is a matched pairs design?
the same participants only complete one condition but they are matched with someone in the other condition based on a characteristic
what are the strengths and weaknesses of a matched pairs design?
STRENGTHS:
- avoids order effects
- reduces risk of demand characteristics
- attempts to reduce individual differences
WEAKNESSES:
- does not account for all individual differences
- higher number of participants needed
how would you write an alternate two-tailed hypothesis?
‘there will be a significant difference in [DV] between [condition one] and [condition two].’
how would you write a null hypothesis?
‘there will be no significant difference in [DV] between [condition one] and [condition two].’
what is a one tailed hypothesis?
these state the (predicted) direction of the experiment
what is a confederate?
an actor who takes part in the research and behaves in the way the researcher asks
what is counterbalancing?
a technique to reduce order effects: half the participants do Condition A, then B, and the rest do it vice versa
what is ecological validity?
the extent to which the findings of a study can be generalised to the real world
define individual differences?
any differences between individuals
what are order effects?
when a previous condition affects the performance in the next condition
define social desirability bias
participants change their behaviour/ responses to fit with social norms and expectations
