Issues with experiments

• Demand characteristics: cues that unconsciously convey the aims of the experiment to the participant or helps them work out how the experimenter wants them to behave.
• Order effects: an extraneous variable caused as a result of the order in which conditions are presented to participants in a repeated measures design. These include practice effects or fatigue effects.
• Counterbalancing: a technique used to counter the order effects by ensuring each condition is tested first or second in equal amounts.
• Investigator effects (experimenter bias): cues from an investigator that influence the way a participant behaves in a study. These can be direct (interaction between ppt and investigator) or indirect (consequence of the design of the study by the investigator).
• Participant variables: when the characteristics of an individual participant in a study affect the conditions of the study. These include age, gender, IQ, memory span, etc.
• Situational variables: features of an experimental environment that influence behaviour or conditions of a study. These act as confounding variables and could be the time of day, temperature of a room, lighting, etc.
• Single blind design: when a participant does not know the true condition of the study, but the researcher does. Prevents ppt seeking cues about the aim.
• Double blind design: when neither the ppt or the researcher knows the aims/hypotheses of the study. This is done by not using the actual investigator of the research as the study conductor. Reduces experimenter bias and demand characteristics.
• Experimental realism: when the researcher makes the study task engaging enough that the ppt pays full attention to the task and not on the observer.