Happy/Sad BMLD cartoon

["Daniel E. Shub" <dshub@xxxxxxxxxxxxx>]

I am curious about the history of the cartoon which denotes the different
stimulus configurations and the corresponding performance used in studies of
binaural masking level differences. I did a quick web search for an example:
http://drgeorgethomas.com/images/successpicture2.jpg

This one looks like the version in Moore's book. My guess is Moore's artwork
was original, but that he did not come up with the concept.

I am curious as to who first conceptualize the BMLD with happy and sad
faces.

Thank you
Dan