If a researcher's audience is biased, they could get the answer that they want versus the correct answer. For example, if a candy company interviews only children who love candy then whatever they were trying to sell would be agreed with. Most little kids love candy, but adults would think more about the consequences in eating candy. A biased audience will have no diversity between people who already agree with the topic and people who don't like the topic.
A bias stand point can affect the understanding of an audience on a topic/event for one main reason in personal belief: stubborn. Most usually, when someone has a bias opinion on something, they can become strictly stubborn when listening trying to persuade them into looking at a different point of view. This can affect the understanding because they may not listen fully, and grasp the whole meaning when their attention is divided unevenly. They may miss very important details in which they never had thought of before.
