Demand characteristics

The demand characteristics of a situation are features that predipose people to act in a particular way. In general, for example, a threatening question demands a submissive answer, it takes a lot to overcome the expectancies inherent in the context.

This phenomena is particularly important in psychological research as subtle signals can encourage certain types of behaviour from participants which can contaminate the results. Subjects often attempt to interpret the experimenters expectations and act on this, trying to be helpful.

The demand characteristics of questionaires etc also require attention in the design stages.