external factors

The knowledge of familiarity with or expectations about, a given situation or previous experiences will influence perception. External factors refer to the nature characteristics of the stimuli. There is usually a tendency to give more attention to stimuli. Any number of these factors may be presented at a given time or situation. It is therefore, the total pattern of the stimuli together with the context in which they occur that influence perception. For example, it is usually a novel or unfamiliar stimulus that is more of a friend among a group of people all dressed in the same style uniform.