Research methods:
Experimental method:
Aims - what the researcher intends to investigate
Operationalised hypothesis - what the researcher believes to be true. Directional – states the
direction e.g. positive/negative. Non – directional – doesn't state the direction e.g. previous
research
Extraneous variables – nuisance variables that are difficult to detect an effect
Confounding variables – can’t establish cause and effect, change systematically with the IV.
Demand characteristics – cues given about the aim that change the behaviour of the
participants.
Investigator effects – the researcher changes their behaviour on the decisions of the designs
Randomisation – the use of chance when designing the investigation to reduce bias e.g.
allocating participants to groups
Standardisation – keeping the procedures the same for all participants otherwise it becomes
extraneous variables
Pilot studies – a trial run of the investigation to road test procedures and see if there needs to
be any changes to the research design
Single blind – when the participant doesn’t know about the aims of the study to reduce demand
characteristics
Double bind – when both the researcher and the participant don’t know about the aims of the
study to reduce investigator effects and demand characteristics
Experimental design:
Independent group design – separate groups for each condition, randomly allocated
No order effects – increases the validity
Participants won't guess the aims – behaviour is more natural
Less economical
Participant variables – reduces the validity
Repeated measures design – participant repeat the experiment again but in a different
condition – counterbalancing to reduce order effects
Participant variables – increases the validity
, Fewer participants needed
Order effects – reduces the validity
Participants can guess the aims – behaviour is not natural – demand characteristics
Matched pairs design – participants are matched according to similar characteristics
Participant variables – increases the validity
No order effects - increases the validity
Time consuming – cannot address all participant variables
Less economical
Types of experiments:
Lab experiment: IV is manipulated and DV is recorded.
Control over EV and CV – establish cause and effect, high internal relaibility
Can easily be replicated, high validity
X demand characteristics, lack internal validity
X lack generalisability, lack external validity
Field experiment: IV is manipulated and DV is recorded
X ethical issues
X no control over EV and CV, can’t establish cause and effect, low internal validity
More natural, can generalise
Participants are unaware that they are being studied, high external validity
Natural experiment: IV is not manipulated, DV is naturally occurring
Has high external validity, real world value
No ethical issues
X natural event occurs rarely, can’t be generalised
X Participants can’t be randomly allocated, CV aren’t controlled
Quasi experiment: IV is pre-existing, DV is naturally occurring
High control, can be replicated
Comparisons can be made between people
X Participants aren’t randomly allocated, CV aren’t controlled
X can’t establish cause and effect
Experimental method:
Aims - what the researcher intends to investigate
Operationalised hypothesis - what the researcher believes to be true. Directional – states the
direction e.g. positive/negative. Non – directional – doesn't state the direction e.g. previous
research
Extraneous variables – nuisance variables that are difficult to detect an effect
Confounding variables – can’t establish cause and effect, change systematically with the IV.
Demand characteristics – cues given about the aim that change the behaviour of the
participants.
Investigator effects – the researcher changes their behaviour on the decisions of the designs
Randomisation – the use of chance when designing the investigation to reduce bias e.g.
allocating participants to groups
Standardisation – keeping the procedures the same for all participants otherwise it becomes
extraneous variables
Pilot studies – a trial run of the investigation to road test procedures and see if there needs to
be any changes to the research design
Single blind – when the participant doesn’t know about the aims of the study to reduce demand
characteristics
Double bind – when both the researcher and the participant don’t know about the aims of the
study to reduce investigator effects and demand characteristics
Experimental design:
Independent group design – separate groups for each condition, randomly allocated
No order effects – increases the validity
Participants won't guess the aims – behaviour is more natural
Less economical
Participant variables – reduces the validity
Repeated measures design – participant repeat the experiment again but in a different
condition – counterbalancing to reduce order effects
Participant variables – increases the validity
, Fewer participants needed
Order effects – reduces the validity
Participants can guess the aims – behaviour is not natural – demand characteristics
Matched pairs design – participants are matched according to similar characteristics
Participant variables – increases the validity
No order effects - increases the validity
Time consuming – cannot address all participant variables
Less economical
Types of experiments:
Lab experiment: IV is manipulated and DV is recorded.
Control over EV and CV – establish cause and effect, high internal relaibility
Can easily be replicated, high validity
X demand characteristics, lack internal validity
X lack generalisability, lack external validity
Field experiment: IV is manipulated and DV is recorded
X ethical issues
X no control over EV and CV, can’t establish cause and effect, low internal validity
More natural, can generalise
Participants are unaware that they are being studied, high external validity
Natural experiment: IV is not manipulated, DV is naturally occurring
Has high external validity, real world value
No ethical issues
X natural event occurs rarely, can’t be generalised
X Participants can’t be randomly allocated, CV aren’t controlled
Quasi experiment: IV is pre-existing, DV is naturally occurring
High control, can be replicated
Comparisons can be made between people
X Participants aren’t randomly allocated, CV aren’t controlled
X can’t establish cause and effect
