Integration

Figure 1

Much work has been put into trying to untangle the processing of stimuli generally from that which projects stuff into consciousness, with reference 1 being a sample of this work. And with it now being clear that there is lots going on which does not reach consciousness. For example, we often react or respond to stimuli in a physical way before they reach consciousness and we sometimes react in such a way when the stimuli do not reach consciousness at all. But my concern here is with the stuff  that does reach consciousness, that does make it.

My allegation is that in the case where visual stimuli are changing too fast for consciousness to be able to cope, the brain substitutes an integration, an average if you will, for the truth. I note that reference 4 suggests that an isolated visual stimulus needs to last for around a tenth of a second, 100ms, to make it to consciousness, bearing in mind that this ‘making it’ is not an all or nothing business; there are shades of making it. See, for example, reference 5, on the perceptual awareness scale (PAS).

Suppose we have the situation, illustrated at Figure 1 above, where the dark blue disc is moving around very fast, in a completely random fashion, in the area marked out by the light blue disc, against the green check background. Something I do not know how to emulate on a PC, but I dare say that with better knowledge of how exactly images get from a file onto the display and with some mathematical trickery it could be done.

But without doing any such emulation, my guess is that what one would see would be a stationary, static image of a disc the size of the outer disc of Figure 1. The colouring of this disc would be smoothed, averaged, but while it would be radially symmetric – any band drawn through the centre of the disc would look the same – it would not be uniform, and it would be bluer towards the middle and greener towards the outside. With the details depending on the relation between the sizes of the two discs and the speed and the detailed specification of the particular kind of random movement involved.

Another guess would be that as the inner disc got small compared with the outer disc, what you would see is a uniform green disc, very slightly blued, against the green background. As the inner disc got large compared with the outer disc, what you would see is a uniform blue disc with a thin, somewhat greened, perimeter.

What is going on is that the brain decides that what you are looking at is the outer disc and it colours each point on that disc by taking the average of the stimuli coming in at the eye, with the eye being able to process stuff a lot faster than it can be delivered to consciousness.

Then, using this principle as a starting point, with more mathematical trickery, one could compute what to expect in the case of the spinning tops noticed at reference 2.

Different again would be fast, linear, uniform motion against a fixed background. Say a car moving across the field of vision.

Figure 2

I suggest that if the motion is fast enough, the best the brain can do is convert the moving object into a striped band along the direction of motion, with the stripes being the average colour of the object for that stripe. In most real world situations, these stripes are going to blend into each other, rather than being sharply defined as they are in Figure 2 above.

Figure 3

If there was more than just colour in the background, it might then be that the band was see through, that the foreground object would become transparent, with the subjective experience perhaps being something like the experience that one gets if one holds one’s finger about half a metre in front of one’s nose and gazes at it with both eyes at once.

A rather different approach is that of what is still called persistence of vision, despite having been discredited, at, for example, reference 3. And rather than trying to account in detail for the continuous movement we see in films, we might think of waving sparklers around in the dark, writing short words with the light, when we were children, probably (here in England) on Guy Fawkes night. But I think I would come to the same answer.

The point of all this being that the shape and appearance of a fast moving object may be substantially altered from its ‘true’, static shape and appearance. Yet another trick of human vision, along with all the other tricks we like to play with. And it is this dynamic shape and appearance, if I can call it that, which get projected into consciousness.

Afterword

There was a homely example of the work of the unconscious this morning, climbing the stairs with a rather too full cup of tea. It is a good idea to pay attention, to gaze at the cup of tea, as one does this, but one has no awareness of the detailed computations needed to get from the signals coming in at the eyes to the stream of commands to the muscles of the arm and hand, a stream which is very much needed to keep the cup moving smoothly up the stairs, with no unwanted accelerations.

And an example of the vagaries of visual image processing in Figure 1 above, which flickers in a very odd way as one pages up and down in that part of what is presently a document in MS Word. Perhaps the same thing will happen in Edge in a few minutes time.

References

Reference 1: Measuring consciousness: Task accuracy and awareness as sigmoid functions of stimulus duration - Kristian Sandberg, Bo Martin Bibby, Bert Timmermans, Axel Cleeremans, Morten Overgaard – 2011.

Reference 2: http://psmv3.blogspot.co.uk/2018/05/paper-puzzles.html.

Reference 3: The Myth of Persistence of Vision Revisited - Joseph and Barbara Anderson – 1993.

Reference 4: Evidence of weak conscious experiences in the exclusion task - Kristian Sandberg, Simon H. Del Pin, Bo M. Bibby and Morten Overgaard – 2014.

Reference 5: Using the perceptual awareness scale (PAS) - Kristian Sandberg and Morten Overgaard - 2015. Chapter 11 of a book published by OUP, but available from ResearchGate if you ask Google (rather than Bing).