What I want to do is think of possible purpose for this. What advantage would the brain have at limiting our conscious experience? In a process of understanding this same question, scientists have come to label the conscious mind as being governed by an attentional system in the same way the brain is governed by a neuronal system. Taking the common idea of attention and turning it into an entire system is an ingenious idea. It allows for an entire slew of questions. What are the laws the govern this system? What is it's purpose? etc. It also allowed me to see the mind and brain as two completely different devices, both governed by different laws and with different purposes.
Here is how I define the two.
The brain is much to busy to deal with our conscious experience. It has so many other jobs to take care that are all of equal importance to our survival e.g. breathing management, heart pumping management, balance management etc. The mind came about as a way for the brain to defuse it's responsibilities - whatever the body needs to be aware of on a conscious level, the brain allocates all the necessary information to the mind and the mind takes care of translating this information into language our consciousness can understand. This doesn't end up being all of the information we receive via our senses, only a fraction. So as the experiment mentioned above illustrates, our brain clearly doesn't think a physical stimulation that lasts only nanoseconds is important enough information to pass onto our mind and therefore we are never made consciously aware of the entire thing. I liken it to a computer. Within a computer there is a CPU and there is RAM. The CPU, like the brain, takes care of everything going on in your computer, even all the things you cannot see on your screen. The running of the fans, the automatic updates, power allocation etc. The RAM, like the mind, is only concerned with what your attention is currently engaged with - what you can see on the screen at any moment. Although the computer receives a ton of information, you are made aware of only that which is relevant to your current attentional needs.
This is the difference between the brain and the mind in I love knowing this because it begs the question, what if we could be made aware of some of these information our brain doesn't think our mind needs? What if we could consciously tap into this information? What kind of world would we experience?
Gazzaniga, Michael S. (1998) The Mind’s Past, chapter 3 and 4. University of California Press. ISBN: 0-520-21320-3