The origins of even familiar objects are frequently mired in mystery. The violin is one such example. Nevertheless, we have recently learned much more about the evolution of the violin over time – specifically, its overall shape and the length of its twin sound-holes. The research yielding this increased understanding focused on the makers of the violin, its so-called luthiers, thus putting behavior prominently into the spotlight. Each of the two studies under consideration proposed provocative parallels between structural changes in the violin and the Law of Natural Selection. But, the more appropriate analysis rests on the Law of Effect shaping the behavior of the luthiers. What is revealed is, first, that increasing the length of the sound-holes amplified the acoustic power of the violin, thus leading luthiers to lengthen the sound-holes; and, second, that the aesthetic tastes of their customers led luthiers to modify the overall shapes of their violins.