The Knee-Jerk "What"

This is a conversation that took place between my eldest son, my husband, and myself tonight.

Husband: says something to son

Son: "What?"

Husband: "You don't hear well!"

Me: (to husband) "You do the same thing to me all the time."

Husband: "What?"

The ADHD people in my family appear to have a bit of extra memory cache attached to their ears.  When somebody says something to them, it goes in that cache.  Sometimes all that gets to the central processing unit of their brains is the fact that somebody addressed them.  So the brain tells the mouth to say "What?" and it does.  I call this the Knee-Jerk What.

This is extremely frustrating, especially when I have a cold and don't feel like repeating myself with a sore throat.  But I discovered something.  Most of the time I can get them to access that cache without having to repeat myself.  Sometimes all it takes is a look.  Sometimes a short reminder to play back the cache.  So, many of my conversations with my husband go like this;

Me: "We need to add oranges to the grocery list."

Husband: "What?"

Me: "You heard me." (see, I just saved myself six words)

Husband: knits brows for a minute, then says "Oh, OK.  Let me get the grocery list."

What's really amazing is just how long what I said can stay stuck in that cache, especially when there is an electronic screen of any sort involved.  I have sometimes waited the better part of a minute before waving my hand in front of my husband's face, only to have him blink and make a perfectly appropriate answer to whatever I said what seems like five minutes ago.  Honestly I would have forgotten.

I do need to find something a little more polite than "you heard me".  Maybe "replay"?  Or "cache"?  I really like the idea of getting it down to one word.

I sure would like to hear the neurological explanation for this.