People only notice something when it stands out to them; otherwise, it is almost invisible. A simple example of this is when you decide to look for a particular make of car, and then you start to see these everywhere. The number of these cars has not suddenly increased. They were always there. It is just your attention to them that has altered. This make of car is now the most noticeable and relevant thing to you. It is salient, so your brain ‘looks’ for it. This is an example of where salience has been brought about by shifting attention to a specific feature.