Much as I enjoyed Jaynes’ book, The Origin of Consciousness in the Breakdown of the Bicameral Mind, I definitely did not agree with its conclusions. Even something that I do not accept can still have little gems in it. One image that has stuck in my memory after all of thirty plus years: Jaynes compared consciousness to the lighted spot of a flashlight in a dark space. The dark space was everything going on in our minds and the little spot of light was what we were conscious of at each instant. We are not conscious of what we are not conscious of. We are not even conscious of the huge extent of what exists in our minds unconsciously. I was reminded of this when looking at some of work of R. A. Rensink.


Rensink has developed a way to show that we are not always consciously seeing what we look at. As well as having something in our vision, we also have to focus our attention on it. It has to be both the focus of our eyes and of our consciousness. He has created pairs of pictures that differ only in some fairly large change – something like an engine being there or not there in the centre of a photograph of any airplane. If the pictures are alternately flashed at the viewer, the difference in the pictures is noticed by the movement/change sensing part of the visual system so that both the eyes and the mental attention go to the area of difference. But if the movement/change sensing process is disabled by putting a blank flicker between the two scenes as they go back and forth, our attention and sight is not drawn to the area of the change. Then we must search the images carefully for some time in order to see the obvious. It feels like we have the whole image in our consciousness but it is an illusion. We only actually ‘see’ what we attend to. Here are demonstrations of the effect.


In this paper, Rensink proposes that there are two structures that are prepared from our raw perception. One has everything (sort of) without the detail. The other has very few things (with only some aspects of them) but in great detail. The first is used to set the scene and direct attention, the other is the attended-to focus. You can have quality or quantity but not all of both.

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