Focal point - survival instinct

What is focal point?

I have read various explanations of this most look something like this:

“Focal point used in art design principles (contrast, size & placement, lines & visual rhythms)”

What ???

Here is my thoughts on what focal point is. I see it as being a lot more fundamental and harking back to our basic survival instincts. Lets take early man, living in his cave or shelter. He get up in the morning and takes a look out of his shelter. What does he see and how does he see it?

If we image that he was looking through a window we can relate that to looking at a graphic image, by supplying a boundary around the image. Very similar to looking at a photograph or a painting in today's terms. But how does he look at this vision? He does not start at the top left hand corner and work his way across and them back to the next line and repeat the process as we would read a book. No, he needs to take the image as a whole. What is he looking for? This is where the survival instinct starts to become apparent. He is looking for 'something' that grabs his attention.  This could be a shape, a colour or something that appears out of the ordinary. This is, in effect, his focal point. He needs this to survive. It could be dangerous. When the focal point is identified an assessment will be made and if it is not deemed dangerous the eye will then start to scan for any other points that could be and so on. A similar function applies to both apparent paths, when the eye will follow to see it anything is taking a particular identified path and also if other eyes are looking in a particular direction. It is our survival instinct that draws our eyes to the same.