Describe and evaluate Gregory’s top down/indirect theory of perceptual organisation (24 marks)
1245 WordsJul 15, 20145 Pages
Gregory proposed that our past experience, knowledge, expectations and motivations can affect how we interpret the visual information we receive, therefore affecting our perception. He suggested that how we see objects is highly brain driven and indirect, and the process takes place so fast that we are unaware of the object in ‘normal perception’; Gregory would say that ‘a perceived object is a hypothesis’.
Perceptual constancies show how the brain compensates to provide a constant perception of things despite changes in the sensory information received by the retina. For example size constancy. When we see a person an extremely small person walking next to a person of normal size we understand that a person cannot physically be that…show more content…
As the brain compensates when objects are further away by perceiving them as bigger than they are actually seen (to estimate their size when close up) the brain also compensates for the line with the arrowhead going away from us (compared to a building going away from us) by making it appear bigger to us and making the line with the arrow head on each end (compared to a building coming towards us) smaller.
Evidence for Gregory explanation of the Muller-Lyer illusion comes from cataract patients who have had their sight restored and see the lines the same length, suggesting visual experiences such as the Muller-Lyer illusion are learnt. More evidence comes from Segall who found that people who live in less square environments do not fall for the illusion, suggesting its results are learnt not innate. However, evidence against Gregory’s explanation of the Muller Lyer illusion comes from children as they are more susceptible to the Muller-Lyer illusion than adults, even though they have had less experience of the carpentered environment. More evidence against Gregory’s explanation comes from Eysenck and Keene who in 1990 suggested that one of the lines is perceived as longer because the overall object is longer due to the fins of the inverted arrow; this suggests the result was just common sense, not the result of