Dr Aris is conducting structured observations to investigate the impact of a new cooperative game on children's prosocial behaviour. During the play sessions, Dr Aris unconsciously smiles and leans forward whenever a child displays cooperative sharing, but remains neutral during other cooperative behaviours.
Which of the following correctly identifies the methodological issue illustrated by Dr Aris's behaviour, and the most effective design modification to control for it?
Demand characteristics; control this by using a single-blind procedure where the children are unaware of the study's aim.
Investigator effects; control this by using a double-blind procedure where an independent observer, unaware of the research hypothesis, conducts the observations.
Social desirability bias; control this by obtaining retrospective self-reports from the children's teachers instead of direct observation.
Observer drift; control this by establishing a more rigorous operationalised behavioural checklist before the study begins.
