Psychology key vocab (Research Methods)

Extraneous variable

any variable other than the IV that could influence the DV

Demand characteristic

Any cue that may inform the participant as to the purpose of an experiment

Participant reactivity

Participants reacting to unnatural behaviour from the investigator

Investigator effect

Any way the investigator themselves may affect the outcome/DV. This could be due to their behaviour or the design of their experiment

Internal validity

Whether the design and conduct of a study can support that a causal relationship exists between the independent and dependent variables.

Control group

The group of participants who receive no treatment. Their behaviour acts as a baseline against which the effect of the IV may be measured

Randomisation

The use of chance methods to control for the effects of bias when designing materials and deciding the order of experimental conditions

Standardisation

Using exactly the same formalised procedures and instructions for all participants in a research study

Order effects

Changes in a participant's performance or behaviour caused by the sequence in which they experience conditions in a repeated measures design

Lab experiment

The researcher manipulates the IV in a controlled environment

Field experiment

The researcher manipulates the IV in an everyday setting

Natural experiment

The researcher has no control over the IV, someone or something else does

Quasi experiment

The researcher cannot manipulate the IV, as it is an existing difference between people, such as age

social desirability bias

To conform to social norms or expectations often to avoid embarrassment or gain approval

Laboratory experiment - Strengths

• Extraneous variables can be controlled

• Randomisation can be done to improve internal validity

• Samples sizes can be selected

• Easily replicated

• Standardisation can be done

Laboratory experiment - Limitations

• Participants may be uncomfortable in new scenario affecting performance

• Hawthorne effect as they need to go into a new place

Field experiment - Strengths

• High ecological validity

• Demand characteristics are less likely to occur as participant may not know they are being studied

Field experiment - Limitations

• Less control of extraneous variables

• Randomisation is not always done

Natural experiment - Strengths

• More mundane realism

• Can investigate IVs that would be unethical or impractical to do in an experiment

• As investigator doesn’t affect IV, investigator effects less likely to occur

Natural experiment - Limitations

• People are not randomly allocated

• Less standardisation

• Extraneous variables likely to impact investigation

Quasi experiment - Strengths

• Can be done when there are practical or ethical reasons why participants can't be randomised

• Can be used in real world settings

Quasi experiment - Limitations

• People are not randomly allocated

• Lower internal validity due to no random assignment

Population validity

The extent to which findings can be generalised to a wider population

Researcher bias

An unintentional influence a researcher has on a study/procedure that affects the results/outcome