control, Demand characteristic investigator effects

• Control, DV and IV are important aspects of research design.
• Extraneous variables are any variable other than the independent variable that might affect the dependent variable and thus affect the results.
• Confounding variables are extraneous variables that are important enough to cause a change in the dependent variable.
• Situational variables are extraneous variables connected with the research, such as temperature, day lighting, materials, etc.
• Participant variables are extraneous variables connected with the research participants, such as age, intelligence, gender, etc.
• Random allocation of participants to their groups, for example in an independent measures design, is an extremely important process in psychological research.
• Random allocation greatly decreases the possibility that participant variables in the form of individual differences, such as mathematical ability, will adversely affect the results.
• To combat the problem of order effects with repeated measures design, researchers can counterbalance the order of the conditions.
• Randomisation is when trials are presented in a random order to avoid any bias that the order of the trials might present.
• Standardisation is the process in which all situational variables of a procedure used in research are kept identical, so that methods are sensitive to any change in performance.
• Demand characteristics occur when the participants try to make sense of the research and change their behaviour accordingly to support what they believe are the aims of the investigation.
• Demand characteristics are a problem as the participants act in a way to support the hypothesis rather than displaying natural behaviour, making the results lack validity.
• Investigator effects are where a researcher (consciously or unconsciously) acts in a way to support their prediction.
• Investigator effects can be a problem when observing events that can be interpreted in more than one way.
• Investigator effects are best controlled by not allowing either the participants or the researcher (investigator) to know the aim of the research and/or identity of the IV.
• This is achieved by using a double-blind experimental technique.
• In a double-blind experimental technique, only the person who originally designed the experiment knows the true aim, and a measure of deception has been used so that the participants and researcher are not aware.