Widely held notions about the effects of heat treatment of flakeable stone were tested by agitating matching sets of regularly shaped pieces of heated and raw chert. The tests indicate that heat treatment changes some of the variables that control flake formation although not necessarily in ways that make flintworking easier. It appears that in order to realize an advan-tage to the practice, the flintknapper must call on his own individual skill to make technical readjustments. -- AATA