Validity; control of variables

Question 1

KEY TERMS; Confounding variables

Answer 1

• a variable that is not the independent variable (IV) under study but which varies systematically with the IV.
• Changes in the independent variable may be due to the confounding variable rather than the IV, and therefore the outcome is meaningless. To confound means to cause confusion.

Question 2

KEY TERMS; control

Answer 2

• refers to the extent to which any variable is held constant or regulated by a researcher.

Question 3

KEY TERMS; external validity

Answer 3

• the degree to which a research finding can be generalised; to other settings (ecological validity); to other groups of people (population validity) over time (historical validity)

Question 4

KEY TERMS; extraneous variables

Answer 4

• do not vary systematically with the IV and therefore do not act as an alternative IV but may have an effect on the dependent variable.
• they are nuisance variables that muddy the waters and make it more difficult to detect a significant effect.

Question 5

KEY TERMS; internal validity

Answer 5

• the degree to which an observed effect was due to the experimental manipulation rather than other factors such as confounding/extraneous variables.

Question 6

KEY TERMS; mundane realism.

Answer 6

• refers to how a study mirrors the real world.
• the research environment is realistic to the degree to which experiences encountered in the research environment will occur in the real world.

Question 7

KEY TERMS; validity

Answer 7

• refers to whether an observed effect is a genuine one.

Question 8

CONTROL of confounding variables.

Answer 8

• consider a class of psychology students conducted the study with the aim of finding out whether participants could do their homework effectively while in front of the tv.
• the independent variable (IV) was whether the TV was on or not. The dependent variable (DV) was the participants’ score on the memory test. If TV is a distraction, the TV off group should do better on the rest.
• but consider this; suppose it happened that all the participants in the tv off condition did the memory test in the afternoon.
• people generally are more alert in the morning and this might mean that it was the time of day rather than the lack of noise that caused the change in the DV. time of day may then be regarded as a confounding variable.
• The experimenter must be careful to control any possible confounding variable. In the case of our experiment participants in both conditions should do the test at the same time of day.

Question 9

CONTROL of extraneous variables.

Answer 9

• in terms of the experiment involving the memory test with and without the TV on;
• some students will have better memories than others. it is unlikely that all the people with better memories would end up in the tv off group.
• if they did, this would act as a confounding variable but it is more likely that this variation is a nuisance variable because we can never be sure that people with good (or bad) memories are likely to be distributed evenly across the two conditions. the extraneous variable of memory ability just makes it more difficult to detect an effect because other factors have an influence.
• these nuisance variables are called extraneous variables because they may affect the DV but not in a systematic way. The are ‘extra’. They also should be controlled if possible. for example, controlling distractions such as noise.

Question 10

REALISM; its aim and also mundane realism.

Answer 10

• the aim of any psychological study is to provide information about how people behave in ‘real life’ - the everyday settings in which life is lived. If set up of a study is too artificial or contrived then the participants will not act as they would normally.
• many things affect the realism of a psychological study. the term mundane realism refers to how an experiment mirrors the real world. ‘mundane’ means of the world - commonplace, ordinary.
• so lack of mundane realism means something is not like everyday experience.
• watching a car accident on film lacks mundane realism because it is not like everyday experience, and this means that the results of the study may not be very useful in terms of understanding behaviour in the real world.

Question 11

Generalisation; what it means and the issues.

Answer 11

• is the point of realism in psychological research that is able to generalise the results beyond the particular unique research setting- in particular to be able to understand behaviour in everyday life (the real world).
• if the materials used in the study are contrived such as film clips, then the behaviour observed may lack realism.
• if the environment in which a study is conducted is contrived and especially if participants are aware they are being studied, the participants behaviour may lack realism.
• even if the environment and materials are ‘natural or real’ a study can still lack generalisability. for example if a study only uses participants at an american university (students) those results may not be applicable to all american people, only american students?

Question 12

What is validity in a general sense?

Answer 12

• refers to how true and legitimate something is as an explanation of behaviour. it involves the issues of control, realism and generalisability.
• consists of two aspects; internal and external.

Question 13

What is internal validity?

Answer 13

• internal validity concerns what goes on inside a study, it is concerned with things such as;
• whether the IV produced the change in the DV or was it a confounding variable?
• whether the researcher tested what she or he intended to test. does the study reflect what it intended to.
• whether the study possess (or lacked) mundane realism.
• to gain high internal validity researchers must eliminate confounding and extraneous variables, and testing what they intended to test.

Question 14

What is external validity?

Answer 14

• external validity is affected by internal validity - you cannot generalise the results of a study that was low in internal validity because the results have no real meaning for the behaviour in question. it concerns;
• the place where the research was conducted (ecological validity). it may not be appropriate to generalise from the research setting to other settings, most importantly everyday life.
• the people who are studied (population validity). if research study involved just students or all men or only amercians etc, then it may not be appropriate to generalise the findings to all people.
• the historical period (historical validity). if a study wa conducted in the 1950s it may not be appropriate to generalise the findings to people today because many other factors affect behaviour now.