Deletion is a process by which individuals filter out information and turn to ‘selective attention’ mode. A common example can be illustrated in the diagram below.
It’s common when people are asked to read out the phrase, that they miss out the extra “the” within the triangle. This is used as an example to further discuss ideas about “blind spots” in our perception, where we look for things which may be right under our noses but can’t find them at all. Our mind filters out information.
