Methodology

Methodology

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…