A potential possibility of why not including Japan is the result they found differs significantly from the reality because of their way of measurements. It seems that the authors concluded as “Cultural Differences” and decide not to use data points of Japan. However The datapoints of India and China seem to coincide with the authors’ hypothesis so they decide not to eliminate them and publish in the journal. This is complete discrimination and I found this extremely dishonest. Shame on the authors and Sciences Journal.