I once read a story, a true story, about a non-observant Jew who had been invited to a dinner at the home of Hasidic Jews. There were bottles of soda on the table for the assembled guests. The non-observant Jew picked up a soda bottle in a back-handed way, his wrist turned, with his thumb on the bottom. Immediately, everyone at the table glared at the man, aghast and horrified. "What did I do?" the confused man asked. It was quietly explained to him that in the Hasidic community that particular wrist motion was reserved for washing the dead in preparation for burial.
I thought of that story while watching the following YouTube video of Penn State Psychology Professor David Rosenbaum (The Central High School of Philadelphia, 229th class, 1970) performing an experiment on grasping objects.