A reinfection of the notorious " Bennett Syndrome" was detected at the last Bluegrass class. It appears that one of the groups that I played in (selected by Dave) started to play "Nine Pound Hammer" however, 3/4 of the way through the song it was apparent that we had been playing "Will the Circle Be Unbroken". All were intent on playing the original song assigned, but autonomically "Circle" was the song that was played. Weird but true!
In browsing the forum, I have learned that there have been other examples of the phenomena. In some cases, I believe that the infectious virus has actually mutated to include other songs and the virus has been spread to other class participants.
For the medically misinformed, the "Bennett Syndrome" was originally observed at JAM in late 2008. It is named after Jim Bennett, the banjo player. While Jim was taking a lead break with his group on their assigned song, "Nine Pound Hammer", the only song he could play was "Circle". No matter how hard he tried and focused he could not get "Circle" out of his brain. After this "performance" by Jim, it was conclusive that symtoms of the syndrome could be both neurological and physical in nature. Fortunately, Jim has almost totally recuperated from the infection, but still avoids both songs whenever possible.
