People perceive objects differently due to three perceptual processes: selective attention, selective distortion, and selective retention. Selective attention means people only notice stimuli that relate to their current needs, are anticipated, or greatly deviate in size from other stimuli. Selective distortion causes people to interpret ambiguous information in a way that fits their preexisting beliefs. Selective retention means people are more likely to remember information that supports their existing attitudes and forget information about competing products.