research issues

• what is an extraneous variable (EV)?

  any other variable other than IV that may effect the DV. if its not controlled. Evs are essentially nuisance variables than do not vary systematically with IV
• what is a confounding variable (CV)?

  like an EV but varies systematically with the IV therefore we cant tell if any change in the DV is due to the IV or CV
• what are demand characteristics?

  cue from the researcher or from the researcher situation that may be interpreted by p's was revealing the purpose of an investigation leading the p's to change their behaviour
• what are investigator effects?

  any effect of the researchers behaviour (conscious or unconscious) on the research outcome (DV) which can include the design of the study and interaction with p's
• what is randomisation?

  use of chance methods to control the effects of bias when designing materials and deciding the order of experimental conditions
• what is standardisation?

  using the same formalised procedures and instructions for all p's
• research issues - extraneous variables

  the key of an experiment is that an IV is changed to see the effects of DV, any other variable that effects the IV or DV should be removed/controlled (EV), researcher identifies it in the start of a study an minimises the influence, many EV are easy to controll e.g age and lighting of the lab = nuisance variables that do not vary systematically with the IV, they do not confound the findings of the study but make it hard to detect a result
• research issues - confounding variables

  CV change systematically with the IV e.g in the energy drink study there are 20 p's and 10 of them are the speedup group, before the study they saw a celebrity, they were excited meaning there was some delay before further p's arrived and by then they were less excited, this unexpected event is an unintended IV - excited or not, so when we analyse the results and the speedup group is chattier we dont know if its the drink or excitement, the emotion varied systematically with IV and this alone could explain changes in DV
• research issues - demand characteristics

  some p's spend time trying to make sense of the situation they are in than being passive in the study, participant reactivity is an EV in experimental research that is hard to control, to make out the situation they use cues which are demand characteristics which allow the p's to second guess the experimenters intentions and the study aims, the cues help p's to at a certain way and please the experimenter (please U effect) or under perform to sabotage the study effects (screw U effect) = p's behaviour is unnatural , and EV that may effect DV
• research issues - investigator effects


  p's reactivity also leads to investigator effects e.g if we speak to a P that is in the speedup group and they meet our theory that they are more chattier, the investigator may unconsciously smile, we may encourage a greater level of chattiness. it is an unwanted influence of the investigator on the research outcome as hugh coolican (2006) points out that it can include expectancy effects or unconscious cues, it can be actions, selection of p's, materials and leading questions
• research issues - randomisation

  randomisation is an attempt to control investigator effects and reduce the effect of confounding/extraneous variables e.g a memory experiment in which p's have to recall the words may be randomly generated but in an experiment in which p's are involved in different conditions it should be random e.g in the energy drink study we want to know what quantity of speedup causes chatiness e.g condition A drink 300ml
• research issues - standardisation

  all p's must be in the same enviroment, experience and get the same information = procedures are standardised such as standardised instructions for each P