Almost everybody has had the feeling of knowing the answer to a question, but not being quite able to say it. this is called the "tip-of-the-tongue" phenomenon, and is a failure of:

As you drive in to school, you hear a random radio-show caller arguing that sun exposure really has not been shown to cause skin cancer and that some research suggests that skin cancer is completely genetic and not related to sun exposure at all. at the time, you think that this is a silly argument and that the caller does not know what she is talking about. however, two months later, you are outside without wearing sunscreen, and you find yourself remembering that you had read something about how the sun actually does not cause skin cancer. this process is evidence that has influenced your attitude