CONTROL OF VARIABLES Flashcards
what is an extraneous variable?
any variable (that isn't the IV) that might have an affect on the dependent variable if it isn't controlled should be identified at the start of the study and their influence minimised 'nuisance variables', they don't vary systematically with the IV - make it harder to detect the result
what are confounding variables?
any variable (other than the IV) that might have affected the DV, so cause and effect can’t be established. the key difference is that they DO VARY SYSTEMATICALLY WITH THE IV
what are demand characteristics?
any sort of cue from the researcher or nature of the study that can be interpreted by the ppts and therefore reveal the purpose of the situation to them. as a result, ppts will act how they think is expected, or to please the researcher - or to sabotage
what are investigator effects?
any effect of the researchers behaviour - can be conscious or unconscious - on the outcome.
design of the study, interaction/selection of ppts, unconscious cues
what is randomisation?
used to minimise investigator effects. uses CHANCE to reduce the researchers influence on the DESIGN of the investigation - EG counterbalancing, random allocation
what is standardisation?
using exactly the same formalised procedures and instructions for all ppts in a research study - same environment, same info, same experience. non-standardised changes will then not act as extraneous variables
what is random allocation?
attempts to control ppt variables in an independent group design - makes sure each ppt has equal chance of being in one condition as any other
what is counterbalancing?
attempts to control order effects in a repeated measures design. half the ppts experience the conditions in one order, the other half in the opposite order.
what are order effects?
an effect of repeated measures… repeating two tasks could cause boredom or fatigue that affects performance, or may improve their performance due to the practice
