Have you ever met someone that has a long held belief that they just won’t change, no matter how much evidence you show them that their belief is not tenable? People seek out and pay attention to information and cues that confirm the beliefs that they have. They don’t seek out, in fact they ignore, or even discount, information that doesn’t support what they already believe.

Useful strategy or bad idea? — Filtering is often a useful strategy, since it reduces the amount of information that you have to pay attention to at any one time. But sometimes filtering can lead to bad choices.
Shooting down a commercial jet — In 1988 the US Navy had a ship in the Persian gulf called the USS Vincennes. One day, while scanning the radar on the screen on the ship, the crew saw aircraft headed their way. They decided early on that the approaching aircraft was not a commercial airliner, but a hostile military plane. They shot down the plane, which did turn out to be a commercial airliner with 290 passengers and crew. Everyone died.
Many factors led to this erroneous conclusion — The situation was stressful , and the room was too dark. There were many unclear or ambiguous pieces of information that made it hard for the crew to understand what they were looking at on their screen. Most significant, however, in the incident, is what they chose to pay attention to and what they chose to ignore.
The crew filtered — Several crew members were convinced from the start that it was a hostile military plane, and from that point on they filtered all the information coming in. The crew had rehearsed the a training scenario many times on what to do when there is a hostile military plane in their air space. They ignored evidence that it was, in fact, a commercial plane, paid attention only to the information that led them to think it was a hostile military craft, and then proceeded to carry out the training scenario. All leading them to an incorrect resolution.
What do you think? Are you aware when you are filtering?