Back wall treatment?


I have a small room which I’ve treated with bass trap in the corners and absoprtion panels at 1st reflection points on the front wall, side walls and ceiling. I am quite happy with the results. I am considering what to do with my back wall. Due to the size of the room I have to sit with my back essentially right up against this back wall. The wall only goes up to about ear level, above that its open to my family room and kitchen.

So my question is what do you suggest for this short back wall? Broadband absorption with something like the GIK 244 panel or diffusion or nothing at all?
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Thank you for the reply. I understand the concept of reflected sound and the amount of delay having an impact on whether or not the brain rejects the reflection so what you said makes sense. What about room modes though?  Since I am against the back wall won't I be at the maximum amplitude of the room mode in that dimension?  If so, a broadband bass trap on the wall directly behind my head should help alleviate that room mode? 
A Skyline diffuser behind the head up on the wall is the best and most reliable product for this problem. Obviously there are a great many room acoustics issues that should be dealt with as best one can from slap echo to standing waves especially in room corners, reflected waves, you name it.
My advice before you spend some money is to temporarily hang a heavy towel, or a rug in that spot to see if it makes a wholesale improvement. If it does, then some nice absorbent treatment there should do the job. I wouldn't recommend diffusion in a spot like that, so close to your listening position. I prefer to be at least 6' or so from any diffusion product.
The fact that the back wall is only ~1/3 to 1/2 high relative to ceiling, I would think that room modes developed due to the front to back distance, would not be that much of an issue. I would try some DIY treatments to test the value of purchasing treatments. 
Thanks guys. I  agree about being too close to the back wall to take advantage of diffusion.  

As for the room modes not being much of an issue due to the height of the wall. I am not sure I understand.  The back wall is right about at ear level so wouldnt that mean I am experiencing the full amplitude of the room mode in that direction?  Are you saying that the room mode amplitude is relative to the height of the back wall?