1. (expectancy effect) A top-down factor in perception generated by particular contexts and/or purposes that contributes to the relative salience of data: see also contextual expectations; perceptual set.
2.Social expectations theory: shared cultural expectations about norms, sanctions, roles, and rankings for routine social interactions in various contexts. DeFleur argues that mass-media socialization has a function in the development of such expectations, and in this way has an indirect and long-term influence on behaviour.
3. In communicative relationships, see contract.
4. In reception theory, see horizon of expectations.
http://www.aber.ac.uk/media/Modules/MC22420/visper06.html Contexts and expectations