Visual Perception and Visual Imagery Essay

3152 Words 13 Pages
If visual imagery and visual perception shared many of the same processes, then much of what is known to date about perception may be used and adapted to be able to understand the more internal and ambiguous process of visual imagery. The question is how much of mental imagery is actually a part of visual perception?

The concept of a ‘unitary mechanism’ has been recurrently mentioned in the text, although little has been said about what it means and implies. This is a term coined by Stephen Kosslyn (2005), he provided a model of visual imagery in which a single visual buffer is used “bottom-up” to display visual percepts and “top-down” to display internally generated images. The main claim is that the brain areas that implement the
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Another type of research is single case studies in which double dissociations have gravely challenged the model, such cases involve patients in which imagery was impaired and perception was speared and vice versa (Shallice, 1988).

Although measures of haemodynamic activity and brain lesion studies provide some insightful information on the issue, other behavioural data is necessary to understand whether visual imagery is processed in the same way as perception. Finke and Pinker (1982) used reaction times as a ‘mental tape measure’ in which participants were required to look at an array of dots, once the dots disappeared and an arrow appeared, participants were requested to indicate whether the arrow was pointing at a previous dot or not. If the distance of the arrow was increased than the reaction time was expected to increase while one imagines scanning the image. This final research begs for the question, would eye movements show the same pattern of ‘scanning’? If visual perception and visual imagery have so much in common, than we might expect that the eye sequences present in visual perception will also be present and similar in visual imagery.

There is strong evidence that this is in fact true, several studies show that spontaneous eye movements occur during visual imagery and in most of the studies the movements reflect the content and spatial relations of the originally perceived object. In a study by Brandt and Stark (1997) the