31 People Confess Things They Didn't Know Until Embarrassingly Late In Life

The reason why we might overlook what seems to be the most obvious thing in the world is the phenomenon known as inattentional blindness. It happens when we fail to see something we didn't expect, usually because our attention is focused entirely somewhere else. 

This is particularly true for objects that are very unlikely to appear, like a unicorn for example. If you saw one, you would be more likely to believe that what you witnessed was a white horse. And the horn must have been just a trick of the light. 

The exact reason why this happens is not yet fully understood. However, such a lack of visual awareness shows that our attentional and processing abilities are limited. Therefore, our brain finds ways of filtering out distractions to focus on what’s most important at any moment. 

Another reason is that we tend to ignore something that isn’t entirely relevant to the situation or won’t help us understand or carry out a task at hand. For example, a gorilla playing a basketball game doesn’t fit into our idea of a basketball game, making it less noticeable when it appears.

Some researchers also suggest that memory limitations might contribute to this. Several experiments have found that people often perceive certain information, they just don’t remember seeing it when asked about it as it wasn’t stored in the part of the brain responsible for short-term memory.

Interestingly, the phenomenon of perceptual blindness is often employed by illusionists who trick the audience’s consciousness by diverting their attention to particular details. For instance, when a person is preoccupied with counting cards that the magician is dealing, they won’t notice that those cards have been set up or arranged in a specific order. 

Or if a magician is taking a card from the top of the deck and using it to point to another one on the table, the audience won’t see that they returned it to the bottom of the deck because their attention was focused elsewhere.