ETYMOLOGY
of uncertain origin;
perhaps from cockle (to move or rock unsteadily; to totter or wobble)
EXAMPLE
“…Their bind was just a Scots pint over-head, and a tappit-hen to the bill, and no man ever saw them the waur o’t. It was thae cockle-brained callants of the present day that would be mair owerta’en with a puir quart than douce folk were with a magnum…”
From: St. Ronan’s Well
By Sir Walter Scott, 1823
Lexicophilia 