Confirmation Bias is the tendency for us to seek out that which confirms our persuasions while avoiding that which conflicts with them.
Though it is a bias it is also a sign of sanity as only an idiot would choose to undermine his own thinking and persuasions. This does not mean that a normal person is not receptive to new truth. They simply do not choose to live a life of uncertainty and dissatisfaction.
Jesus is the Truth. EVERYTHING that we NEED to know is found in Him. Once you find the Pearl Of Great Price you don't go shopping it around.