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Gregory’s Top-down Theory . Top-down Theories. Top-down theories suggest that we combine information from a variety of different sources in order to construct our perception of the visual world. Top-down theories.
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Top-down Theories • Top-down theories suggest that we combine information from a variety of different sources in order to construct our perception of the visual world.
Top-down theories • Theorists such as Gregory suggest that there is insufficient information provided by the senses for us to make sense of what we are seeing. • Therefore we use our existing knowledge (schemas) to fill in the gaps. • Perception is an active and constructive process.
Hypothesis Testing • Gregory suggests perception is governed by hypothesis testing. • For example we might look at a scene and see something we cannot identify. • We will work out what it is by deciding what object would be most likely to be in that situation.
Hypothesis Testing • This means that it is possible to test and accept hypotheses that are wrong. • This is the reason, according to Gregory, we experience visual illusions. • Ponzo illusion
Factors Affecting Perception • Top-down theories have their origins in the work of Gestalt Psychologists. • One of their fundamental ideas is that we try to find order in the world around us. • They identified a number of different examples of this.
Gestalt Psychology • These ideas can be applied in other situations too for example biological motion. • Biomotion
Perceptual Set • An example of top-down processing is perceptual set. • A person’s expectations about what they are seeing can affect what they perceive.
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Conclusion • Perception involves both top-down and bottom-up processing. • Gregory acknowledged that people use sensory cues especially those such as texture gradients or motion parallax to make sense of the world. • But he also believed that people use their knowledge to help construct their understanding of what they are seeing.