Aldsworth and Bridgers found that keeping this variable constant at a factory caused workers to develop low-level sensory deprivation. An increase in this variable provided by “moontowers” increased (20[2])commerce (20[4])and was thought (20[1])to decrease crime (20[2])when installed (20[3])in several (20[1])cities (20[3])in the 19th (20[3])century. (20[4])Elton Mayo (20[1])found that worker productivity did not change with this variable but did change (20[1])when workers were observed, (20[2])a phenomenon dubbed the (*) Hawthorne Effect. (0[1])People are exposed to less of this variable per day at the borders (10[1])of time zones, the negative (10[1])effects (10[1])of which (10[1])have been used to justify not making a timekeeping policy (10[1])permanent. For 10 points, people with low levels of vitamin D may not be exposed (10[1])to enough “natural” form of what phenomenon? ■END■ (10[2])