So what does this mean if you are designing a website or something on a computer screen? It means that you can’t assume that just because something is on the screen means that people see it. This is especially true when you refresh a screen and make one change on it. People may not realize they are even looking at a different screen. Remember, just because something happens in the visual field doesn’t mean that people are consciously aware of it.

https://www.blog.theteamw.com/2009/10/25/100-things-you-should-know-about-people-1-inattention-blindness/