853317
| Pregunta | Respuesta |
| Control of extraneous variables, demand characteristics and investigator effects | all of these are involved in research methods and studies |
| Extraneous variables | -factors which can influence the DV other than the IV are called extraneous variables -it is important to control them, so that the DV isn't being affected by the extraneous variable but is being affected by the IV. -if an extraneous variable is not controlled, it becomes a confounding variable. |
| Psychologist example | -psychologist investigates the effect of caffeine on reaction time. -1 group of Pps are given a cup of coffee containing 10mg of caffeine, the other group are given a cup with 2mg of caffeine. -Pps then had a task where they had to click on a moving target on a computer screen; the psychologist measured how many seconds it took each Pp to click on the target. -the first group was tested at 9am on a bright sunny morning -the second group was tested at 3pm on the same day with the rain hammering on the windows of the testing room. -IV- the amount of caffeine in the cup (10mg or 2mg) -DV- reaction time to clicking on moving targets on a computer screen. -potential extraneous variables- age, gender, disability, sleep, weather (cold fingers- slower reaction time), eye sight. -situational variables, participant variables are a part of extraneous variables -extraneous variables can also include things such as demand characteristics and investigator effects. |
| An example extraneous variable and how to control it | participant variable- Gender they could only test on one gender, just males or just females. -age -use people of around all the same age range 40+, 50+ etc. |
| Demand characteristics | Features of an exp that help Participants to work out what is expected of them, and lead them to behave in certain predictable ways. -this is a problem that can occur in many kinds of studies is that the Pps behaviour is influenced by demand characteristics. |
| reducing demand characteristics | single blind design -this is a procedure in which the Pps are not informed of the condition in which they have been placed. |
| Investigator effects | -this is a term used to describe subtle cues or signals from an experimenter that may affect the performance of Pps in studies. -investigator effects include any cues (other than the IV) from an investigator that encourage certain behaviour in the participant, leading to a fulfilment of the investigators expectations. -such cues act as an extraneous variable. -the way in which an investigator asks a question may lead a participant to give the answer the investigator 'wants'. -alternatively, the way the investigator responds to a Pp may encourage some Pps more than others. -e.g. research has found that males are more pleasant, friendly and encouraging than with other male Pps. -another key issue is that of experimenter bias: experimenters have a clear idea of what they expect or hope will be the results of their study, so there may be bias, however unintentional, when they are recording the data. -we can define investigator effects as: aspects of the researcher's appearance or behaviour that can also lead Pps to think that they should act in a particular way. |
| reducing investigator effects | double blind design - a procedure where neither the Pp nor the experimenter knows the precise aims of the study. -this reduces experimenter effects. |
| extraneous variable - 4 types | 1. participant variables 2. situational variables 3. demand characteristics 4. investigator effects |
| 1. participant variables | -anyone involved in the study -all factors to do with the person involved -age, gender, intelligence, attractiveness, appearance |
| 2. situational variables | -environmental factors -weather, busy/ quiet environment |
| 3. demand characteristics | -they occur when Pps try to make sense of the research situation they find themselves in and act accordingly |
| 4. investigator effects | -result from the effects of a researcher's behaviour and characteristics in an investigation. |
| Example studies | Dabbs et al (2001) -investigated whether Pps levels of testosterone had an effect on how nervous they were in social situations. Situational variables: where they are -who they are with -what type of social situation -level of emotion towards people involved -amount of preparation Participant variables:- whether they have a disorder -gender (boys have more testosterone and high levels in teen years - age) - intelligence -age of person or people around them -level of emotion towards people involved -personality |
| Example studies | Kiecolt- Glaser et al (1984) -investigated the effect that the stress of exams has on the immune system. Situational- friends that have colds -season of exams -school-life situation before exams -work being put into exam (amount of hours prep) -positive experience of exams Particpant v- sleep -family situations at home -age -immune system good or bad -gender -diet -exercise -positive experience with exams. |
| Example studies | Sylva et al (2003) -investigated whether some types of pre-school experience were more effective than others at promoting children's development situational v- pre-school teachers -area it is based in -role model behaviour shown -resources for the pre-school (learning equipment) participant v- intellect of child -age -gender -diet -sleep (tiredness) -attachment/relationship to parents -parental input -siblings- ranking -personality -mental state |
| how to control it | pre school -select Pps with similar diets -same age (range or in particular) - one gender (all girls or all boys) -in one social situation exams -keep them all in the same season -age -only have strong/healthy immune system Pps. |
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