Research Issues

Extraneous variable

• Any variable, other than the IV, that may affect the DV if it is not controlled. They are essentially 'nuisance variables' that do not vary systematically with the IV, making it harder to detect a result

• Relatively easy to control such as the age of participants, lighting in the lab, etc.

Confounding variables

• A kind of extraneous variable but the key feature is that they vary systematically with the IV. Therefore, we can't tell if any change in the DV is due to the IV or because of this.

Demand characteristics

• Any cue from the researcher or from the research situation that may be interpreted by participants as revealing the purpose of an investigation. This may lead to a participant changing their behaviour within the research situation as they 'second-guess' the experimenter's intentions as well as the aims of the study. Behaviour is not natural- an extraneous variable that affects the DV

• May also act in a way that is expected and over-perform to please the experimenter, or under-perform to sabotage the experiment

Investigator effects

• Any unwanted influence of the investigator on the research outcome, this can include expectancy effects and unconscious cues. May also refer to actions of the researcher related to the study's design (e.g. selection of participants, the materials, the instructions, etc.)

Randomisation

• The use of chance methods to reduce the researcher's unconscious biases when designing an investigation (controlling investigator effects) (alternative to counterbalancing)

• E.g. a memory experiment involving participants recalling from a list- order of the list should be randomly generated so the position of each word is not decided by a researcher

Standardisation

• All participants should be subject to the same environment, information, and experience. There is a list of exactly what will be done in the study, including instructions, that have gone through this, that are read to each participant