The 4-day work week has been an idea pitched by many organizational psychologists, that believe that it could possibly lead to more productivity from workers. The theory behind the 4 day work week is that workers will be more motivated and effective at work in gratitude for the reduced work schedule. Microsoft’s Japan branch tested the theory out, with successful results as a positive correlation was found between a 4 day work week for employees and productivity.
See "Microsoft Japan’s four-day week is new evidence that working less is good for productivity", Cassie Werber, Quartz at Work, November 4, 2019