Validity: Control of Variables


Invariably, studies in psychology involve a trade-off between control and realism. The greatest control can be achieved in a lab.
Mind Map by MNDA T, updated more than 1 year ago
Created by MNDA T almost 4 years ago

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Validity: Control of Variables
  1. Control
    1. Confounding Variables (CV)
      1. If you did your independent groups experiment at different times of the day (morning & afternoon) it may change the DV. This means the time of day is the confounding the variable.
        1. Experimenters may claim the IV caused the DV to change but this may be caused by the CV.
          1. Consequently, experimenter may not have tested what they wanted to test.
            1. Influence of different variable has been tested instead.
              1. Experimenter must be careful to control any possible CVs (e.g test at same time of day).
          2. Extraneous Variables (EV)
            1. Some participants may have better memories than others.
              1. It is more likely that this variation is a nuisance variable because we can never be sure that people with good or bad memories (in this e.g.) are likely to be distributed evenly across the two conditions.
                1. These nuisance variables are EVs because they may affect the DV but not in a systematic way.
                  1. Are 'extra'.
                    1. Should be controlled as much as possible.
                      1. e.g. controlling noise distractions
                      2. More difficult to detect an effect because other factors have an influence.
                2. Realism
                  1. Generalisation
                    1. The point of realism is to be able to generalise the results beyond the particular unique research setting.
                      1. If the materials used in the study are contrived e.g. film clips, then behaviour observed may lack realism.
                        1. Even if the environment and materials are 'natural' or real (high realism), a study can lack generalisability.
                          1. e.g. if participants in a study are American uni students, it may not be reasonable to generalise the findings to the behaviour of all people because Americans (and students) may have unique characteristics that may set them apart from others.
                          2. If the environment of the study is contrived and esp. if participants know they are being studied, their behaviour may lack realism.
                            1. Psychologists always ask themselves: "To what extent can I generalise these findings to everyday life?"
                          3. Aim of any psychological study is to provide info about how people behave in 'real life'.
                            1. If the set-up of a study is too artificial or contrived, participants won't act as they will normally.
                              1. Many things affect the realism of a psychological study.
                                1. Mundane Realism
                                  1. 'mundane' - of the world (commonplace, ordinary)
                                    1. Lack of it means something is not like everyday experience.
                                2. ADD PICTURE FROM PG 113 OF TEXTBOOK
                                  1. Validity
                                    1. Refers to how true or legitimate something is as an explanation of behvaiour.
                                      1. Often assumed that validity is about 'being correct'. This is both right and wrong.
                                        1. Right - a researcher seeks to find out whether their hypothesis is true/correct.
                                          1. Wrong - ...if you think that being correct means finding out that the predicted expectations have been confirmed.
                                            1. Validity is not about confirming your expectations.
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