How many processing pathways? A study of Monkey vs Human response time

A series of visual processing experiments were conducted on a series of human and monkey subjects [3]. These experiments were conducted under extremely tight time constraints (stimuli for 30 ms, response required in less than 1s) and were based on flashing the subjects a picture and requiring a response to a given question for the series of pictures, like ``is there a human/monkey in the picture''. Yes or no responses were required. The pictures also varied in degrees of sharpness and colour(i.e. colour or black and white). It was noticed that the monkeys have a generally faster reaction time(250-300ms) than the humans(350-450ms), although they had roughly equal success rates(90% and 94% respectively). While this can be explained by the fact that humans have larger brains and that within the cortical areas the conduction velocity of the axons can be relatively slow, it is the other finding which is significant.

While colour was found to have no effect, the more important observation is that the subjects continued to perform significantly above chance levels until the sharpness of the picture was at a contrast of 3.1% of normal levels. What is interesting here is that at contrast levels of twice to three times of that, it is already very difficult to actually comprehend what is in the picture, even without a time limit. This, coupled with the fact that the human subjects could not give an explanation as to why they chose the pictures they did for the lower contrast levels, nor could they identify what the picture was, provides a very interesting insight to how the human mind might possibly work. The reason given was that humans might share some of the more basic, coarse and faster processes with monkeys, inherited from their common ancestor and when faced with great time constraints, they are forced to rely on them.

What this would mean for a possible AI model is that, to be similar to a human, it should have not one, but two processing pathways: one for higher reasoning at the cost of speed when time is not a constraint, and one for making swift decisions when time is a constraint. This second processing pathway should also be inherent to a certain extent and also preferably have no need for modification.

Another thought concerning this second pathway is that it could possibly be the reason for ``gut feelings'' and ``intuition'' in humans. Since the humans involved in the study demonstrated the ability to correctly detect and assess the pictures even though their conscious minds could not, it is very much likely that what is called ``intuition'' might just be the perception of stimuli on a subconscious level, which triggers biologically appropriate responses, in spite of the conscious mind being unable to locate the reason for those responses. This might possibly be the key to giving an AI the equivalent of ``intuition''.