experiments Flashcards
types of experiments
- laboratory
- field
- quasi
laboratory
the independent variable is manipulated by the researcher and the experiment is carried out in a lab or other highly controlled setting away from the participants normal environment.
field experiment
the independent variable is manipulated by the researcher but the experiment is carried out in the participants normal environment
quasi experiment
the independent variable is naturally occurring and is not manipulated by the researcher (i.e. cloudy conditions vs sunny conditions).
advantages of lab experiments
- controlled settings reduces the effects of extraneous variables
- increases internal reliability as the procedure would be standardised and can be replicable many times
disadvantages of lab experiments
- low ecological validity as due to the unnatural behaviours, it cannot be generalisable to real life settings or scenarios
- more effort, time and money in order to conduct research
advantages of field experiments
- controlled settings
- high ecological validity as it can be generalised to a real life scenario
- produces more natural behaviour
- high internal validity
- less effort to set up and conduct
disadvantages of field experiments
- demand characteristics where participants will know that they are being observed and will alter and adapt their behaviour in terms of what the study is about
- higher chance of extraneous variables which would alter and influence the results
- low internal validity as participants may have different experiences
advantages of quasi experiment
- high ecological validity as the iv is not manipulated and can generalise to real life scenarios
- helps us study variables that we cannot manipulate
disadvantages of quasi experiment
- difficult to conduct in some situations
- cannot control some participants to variables that may influence the results
experimental designs
- repeated measures
- independent
- matched participants
repeated measures
using the same people in each condition
independent measures
using different people in each condition
matched participants
using different people in each condition but an attempt is made to make the participants as similar as possible on certain key characteristics. this is one by testing the individual on key characteristics, pairing them based on similar scores and then placing one member of each pair into each group
advantages of repeated measures
- removes the effects of any participant variables on the cause and effects as participants take part in both conditions
- easier to obtain sample as fewer participants are needed overall
disadvantages of repeated measure designs
- demand characteristics as participants may try to identify what the experiment is about by predicting and altering their behaviour
- order effects may influence results unless counter-balanced
advantages of independent measure design
- reduced demand characteristics as the participants in each condition are unaware of the other
- ## no order effects as participants only take part in one condition.
disadvantages of independent measure designs
- high levels of effort to collect more participants as you need different people
- findings may be influenced by participant variables
advantages of matched participant design
- reduced effects of participant variabes
- no order effects as different participants for each condition
- lower chance of demand characteristics as participants only do one condition
disadvantages of matched participants design
- more effort and time consuming to find sample
- cannot control all of the extraneous variables by perfectly matching participants
types of extraneous variables
- participant variable
- situational variable
participant variable
characteristics of the individual participant the may influence the results
i.e. age, intelligence, motivation, experience, gender
situational variable
any feature of the research situation which may influence a participants behaviour and therefore the results
i.e.
order effects.
environmental factors
demand characteristics
order effect
which is where if doing the same activity twice, participants may do better the second time because of practice or boredom.