The concept of Selective Attention is discussed in Chapter 6 - a function where we subconsciously determine what we focus on when viewing something. This is done to prevent overstimulation in the retina, and to ensure that we focus on what matters most. This bodily function, in theory, sounds ideal. But when you factor in the tendency of people to selectively view only what they'd like to see on top of the natural instinct, there is a guaranteed overlap.
So, by the time Selective Attention filters through what we see, and then we use our own emotions and desires to determine what we truly want to focus on, out of what we actually see with our two eyes actually gets perceived in the brain? A majority of it is simply fixations, such as only focusing on a coffee stand while walking a crowded building on college. To the tired, caffeine craving mind, the coffee is the only priority. Standing in line for coffee is then the next logical step, so there truly is no need for the brain to focus on anything else related to the surroundings.
But how much is lost in that focus? Perhaps the directed gaze resulted in a loss of focus on a beautiful girl staring right back at you, or an old friend who you haven't seen in a long time whose back was turned? Maybe someone just dropped a $20 bill - which would buy a lot of coffee - right in front of you, but you're still too busy fixating over how long the line is? There is no doubting the scientific proof that our brains filter things out for a reason, but what if we could alter what we focused on based on the actual significance, rather than the perceived? What if we could filter our concentration to be based on what is the most important aspects of our surroundings, rather than what is viewed as what can fulfill our most current need? We may miss out on what we were looking for in the first place, but could gain so much more - all through a simple change of focus.