experimental methods

What is an extraneous variable? (EV)

anything other than the IV which impacts the DV

Explain the two main types of EVs

• situational - environment e.g noise (or experimenter effect where the researchers behaviour affects ppts)

• participant variable - any individual characteristic which could impact performance

What is operationalisation?

making behaviour measurable

What is meant by reliability? + How do we improve it in our experiments?

• the consistency of a measure (would you achieve the same result if the expriment was replicated?)

• using standardised procedures

What is meant by validity?

how accurate results are

Explain the two types of validity

• internal validity - how controlled a study is e.g evs, demand characteristics, social desirability

• external validity - generalisability, ecological validity (situation), mundane realism

2 pros and 2 cons of lab experiments

+: control over evs so easy to measure cause and effect

+: can use standardised procedures so improved reliability

-: less representative of real life scenarios so decreased reliability

-: ppts may work out aim of study leading to demand characteristics so decreased validity

2 pros and 2 cons of field experiments

+: reflective of real life scenarios so increased mundane realism and validity

+: ppts do not always know they are watched so decreases demand characteristics

-: limited control over evs so hard to identify cause and effect so decreased validity

-: less standardised procedure, cannot easily be replicated so decreased reliability