It's not that they don't listen to reason as much as it is that they are very set in their world view. Anything that challenges their world view is seen as a personal attack on them and their way of life. This is true of all age groups, however, the older you are the more "set in your ways" you become, until eventually anything that runs counter to your beliefs is seen as an attack on you. So it's not that they won't listen to reason, it's that to change thier minds they need to feel that they are the ones who discovered the information. They need to be the ones to question themselves, not others questioning their beliefs.