How can attitudes and values influence effective communication

Let's look at some examples of attitudes and values:

1) all people are equal
2) some nationalities are better than others
3) women should be respected
4) people who are not smiling should not be trusted.

If someone holds attitutes like this, they might end up displaying less respect to some of their speakers, which will in turn mean that they will not listen to them as carefully: this will make the communication less effective.