• Created by: Maki_04
  • Created on: 08-10-21 10:23


Experimental Methods

Laboratory Experiments

  • Controlled environment
  • +Artificial and controlled environment (low ecological validity: does not reflect real life situations)
  • -Experimenter manipulates IV to see the effect on the DV (high levels of demand characteristics because participants are aware: more likely to change behaviour)
  • +High levels of reliability (consistent results because standardised procedures are used: extraneous variables are controlled, identify causal relationships)

Field Experiments

  • Natural environment
  • -Situational variables
  • +High level sof ecological validity (natural environment)
  • +Particpants less likely to change behaviour (reduces demand characteristics)
  • -Ethical issues involved (no consent: should debrief but not always possible)
  • -Low levels of reliability (extraneous variables: different particpant variables, situational variables)
  • +Researcher effects less likely to effect results (beliefs, ecpectations, behaviour towards particpants)

Natural Experiments

  • Meaure naturally occuring cause and effect relationships
  • Very little control
  • +Reduce demand characteristics (natural so behaviour will be natural)
  • +High ecological validity (realistic and can be directly applied to real life behaviour)
  • -No control over IV or the extraneous variables
  • -Unable to select particpant variables
  • -Impossible to replicate

Operationalisation - a good hypothesis should be precise and written in a testable form

Null hypothesis - states that the IV will not affect the DV and any difference in results is due to chance

Experimental hypothesis - states that the IV will affect the DV, there will be a differnece in results. can have one or two tails:

  • One tail (directional) - states the kind of difference or relationship between the two conditions
  • Two tailed (non-directional) - predicts that there will be a difference between…


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