Because they represent our past experience, and because past experience is useful for prediction, our schemas influence our expectations about future events. For instance, if you have watched Italian movies or if you have visited Italy, you might have come to the conclusion that Italians frequently gesture a lot with their hands when they talk—that they are quite nonverbally expressive. If so, this knowledge will be contained in your group schema about Italians. Therefore, when you meet someone who is Italian, or even when you meet someone who reminds you of an Italian person, you may well expect that he or she will gesture when talking.
Having a database of social knowledge to draw on is obviously extremely useful. If we didn’t know or couldn’t remember anything about anyone or about anything that we had encountered in the past, our life would be very difficult because we would continually have to start our learning over again. Our schemas allow us to better understand people and help us make sense of information, particularly when the information is unclear or ambiguous. They also allow us to “fill in the blanks” by making guesses about what other people are probably like or probably going to do in cases where things are uncertain. Furthermore, the fact that different people have different past experiences—and thus that their schemas and attitudes are different—helps explain why different people draw different conclusions about the same events.
Once they have developed, schemas influence our subsequent learning, such that the new people and situations we encounter are interpreted and understood in terms of our existing knowledge (Piaget & Inhelder, 1962; Taylor & Crocker, 1981). Imagine, for instance, that you have a schema—and thus an expectation—that Italians are very expressive, and you now meet Bianca, who has arrived at your school directly from Rome. You immediately expect her to be outgoing and expressive. However, as you get to know Bianca, you discover that she is not at all expressive and does not “talk with her hands.” In fact, she is quite shy and reserved. How does existing information influence how you react to the new information you receive?
One possibility is that the new information simply updates existing expectations. You might decide, for instance, that there is more variation among Italians in terms of expressiveness than you had previously realized, and you might resolve that Italians can sometimes be very shy and thoughtful. Or perhaps you note that although Bianca is Italian, she is also a woman. This might lead you to change your schema to believe that although Italian men are expressive, Italian women are not.
When existing schemas change on the basis of new information, we call the process accommodation. In other cases, however, we engage in assimilation, a process in which our existing knowledge influences new conflicting information to better fit with our existing knowledge, thus reducing the likelihood of schema change. In the scenario above, if you used assimilation, instead of changing your expectations about Italians, you might try to reinterpret Bianca’s unexpected behavior to make it more consistent with your expectations. For instance, you might decide that Bianca’s behavior is actually more expressive than you thought it was at first, or that she is acting in a more shy and reserved manner because she is trying to impress you with her thoughtfulness or because she is not yet comfortable at the new school. Or you might assume that she is expressive at home with her family but not around you. In these cases, the process of assimilation has led you to process the new information about Bianca in a way that allows you to keep your existing expectations about Italians more generally intact.