The managers' argument is based on the assumption that eliminating breaks will lead to more work hours and therefore higher productivity. However, if it is true that continuous work without breaks leads to fatigue, which in turn causes efficiency to decline over time, then the extra work hours gained by eliminating breaks would not necessarily translate into increased productivity. In fact, the productivity per hour could drop as employees become tired.
Let's briefly consider the other answer choices:
A) While discussing work-related matters during breaks might boost creativity, it does not directly address the core issue of declining efficiency due to fatigue when breaks are eliminated.
B) The fact that the study controlled for various factors supports the validity of the study's findings but does not weaken the managers’ argument.
C) Higher turnover rates might indicate other issues (such as dissatisfaction) with break-free policies, but turnover does not directly measure productivity during work hours.
D) Higher job satisfaction from taking breaks is a positive outcome, but it does not directly challenge the managers’ claim regarding productivity gains from eliminating breaks.
Therefore, E most seriously weakens the managers’ argument by showing that continuous work without breaks leads to fatigue, which reduces efficiency over time, ultimately negating the potential benefits of extra work hours.