Dear Dr. Workaholic:
Please tell me why my husband doesn't listen to me?  We can be relaxing at the table or in the living room, or on the patio and he will be looking right at me, but I realize, he's not listening.  I have heard other women complain about this same thing about their men.  Is it my voice - should I talk low and sultry, or perhaps stand on my head?  It is because I am there all the time and its nothing new....   surely someone wise and noble, like yourself, has the answers

Dear Unheard and Ignored: The problem is not wax in the ears, it's focus in the brain.  There are two basic causes that I am aware of:       
1.  When the person on the receiving end is either seriously involved in a self-examination then they will not hear any outside influences, and that has nothing to do with anything except the propensity of that person to have deep thoughts and introspective examinations.  Professor types.  Many people have never experienced a deep thought, but others can will themselves to go into that state frequently.        
2.  When the person on the receiving end (note I DID NOT say on the listening end) perceives that what someone else is saying to them is either irrelevant, repititious, or offensive, they can close their mental preceptors to outside intervention and even though they are looking right at you, they can't hear you.  They are in a catatonic-like state for that moment. 

Successful relationships thrive when the person speaking understands that one or the other of these states may well be in place, and it doesn't matter at all which is the cause - the effect is what we are looking for - and so they can through some attention getting word(s), tone or movement, seek to jar the person out of their state so that they are forced to be receptive to what you are saying.  Kind of like kicking the donkey in the butt before, not after, you tell them to move so that they can associate the kick with movement, not with more talking.