Research methods P2

• Laboratory experiment


  controlled conditions

  manipulates the iv to measure the effect on the dv

  + high control over extraneous variables - can establish cause and effect

  -lacks external validity - lacks ecological validity so findings cannot always be generalised to settings beyond the lab
• Field experiment

  natural conditions

  manipulates the iv to measure effect on dv

  any location that isn't a lab

  don't know they are taking part

  + high levels of ecological validity in comparison to lab studies - more representative

  -less control over extraneous variables

  -ethical issues - can't give informed consent to take part so may breach the privacy rights
• Natural experiment


  doesn't manipulate the iv instead examines the effect of an existing iv on the dv which is naturally occurring (eg flood or earthquake)

  + high levels of external validity, high in ecological validity as not manipulated artificially

  -no control over extraneous variables so difficult to accurately asses the effects of the iv on the dv

  + unique insight to real life situations
• Quasi experiments


  naturally occurring iv (but one that already exists eg eye colour or age), measuring its effects on the dv

  don't have to be conducted in a natural setting

  -participants can't be randomly allocated to conditions to remove bias

  -methodological issues - no control over the environment and extraneous variables
• covert observation


  when the participant doesn't know they are being watched

  • one way mirror
  • joining group as member

  + lower chances of investigator effect as they are hidden so less likely there behaviour will have a direct impact on participants

  -ethical issues - can't give fully informed consent or have the right to withdraw
• overt observations


  observations are open and the participants know they are being watched

  • fi;ming publically
  • joining a class and telling students you are carrying out an observation

  + more ethical - can inform of aims and obtain consent

  -investigator effect - investigator influences behaviour of the participant in a way that is not intended eg body language or facial expression
• participant observation


  person who is conducting the experiment also takes part in the activity being observed - either covert or overt

  + gain in depth data since can gain unique insight, unlikely to overlook any behaviour

  -investigator effect - presence of investigator may influence the participants behaviour
• non-participant observation

  observer doesn't participate in the activity being observed. quite common in educational setting eg sitting in the corner of the room

  + investigator effect is less likely as observing from a distance and might not be visible at all

  -lack of proximity so might miss behaviours of interest
• naturalistic observation


  carried out in an unaltered setting where the observer doesn't interfere eg shopping centre as people go about their daily business

  + high levels of ecological validity

  -issues of reliability as recording behaviour that is naturally occurring is difficult for the exact conditions to be replicated
• controlled observation


  under strict conditions such as observation room or lab settings.

  + replicated easily to check reliability - highly controlled & standardised procedures

  -lower levels of external validity