controls Flashcards
what are the 4 types of extraneous variables
→ demand characteristics
→ participant variables
→ situational variables
→ investigatory effects
what is the purpose of an experiment
the purpose of conducting a piece of research is to see if you IV affects / changes your DV
what is cause and effect
psychologists try to control extraneous variables so they don’t become confounding variables → experiments can show cause and effect
what are situational variables
situational variables are those features of a research situation that may influence pps behaviour
→ e.g. order effects, time of day, temperature, noise
what are demand characteristics
→ clues that may help pps to guess the aim of the study and as a consequence change their behaviour
→ demand characteristics results in pps behaviour no longer being natural and therefore, they are extraneous variables that may affect the DV - lowering the internal validity
what are pp variables
→ any characteristic of individual pps
→ these extraneous variables are related to individual characteristics of each pp that may impact how he or she responds → ethnicity, mood, anxiety, intelligence and other characteristics that are unique to each person
→ pp variables act an extraneous variables only if independent group design is used
what are investigator effects
→ any (unintentional) influence of the researcher’s behaviour / characteristics of pps data / outcome
→ the cues may be unconscious nonverbal cues, such as muscular tension or gestures or vocal cues e.g. tone of voice
what are pps variables examples
→ gender
→ age
→ moos
→ background
→ ethnicity
→ IQ
→ personality
→ memory
→ beliefs
what are extraneous / confounding variables
something other than the IV that affects the DV, must be controlled to create a valid style
what is counterbalancing
→ relevant to repeated measures design and is implemented as follows → the research splits the pps in half, one group completes the conditions in the order A followed by B
the other group completes the conditions in order B followed by A
→ counterbalancing is used to control order effect - practice effects, fatigue and boredom
what is standardisation
→ standardisation is used to describe the identical produce set up in an experiment across all conditions / pps which involves
→ instructions given to the pps
→ briefing prior to the procedure and debriefing after procedure has taken place
→ number of pps per conditions
→ timings: each condition of the IV should run the same amount og time and the same time of day
→ materials: identical materials should be used
implementing standardisation allows the research to be replicated and reliable
how can pps variables be controlled
→ using an independent group design by randomly allocating participants to groups - ensure an even spread of important characteristics (outliners)
→ another way to control pv is to used a matched pairs design or repeated measures design
how can situational variables be controlled
→ using standardised procedures to ensure that all participants are tested under the same conditions → if different procedures are used the different outcomes may be due to the procedures and not the IV
how can investigator effects be controlled
→using a double blind design
→→ this is when both the participant and the person conducting the experiment don’t know the aims of the experiment, therefore the investigator cannot affect the participants performance
