This weeks Watchtower study (September 2017) about self-control states: "Clearly, people who lack self-control are causing problems for themselves and for others. And the problem of lacking self-control is worsening. Self-discipline was studied in the 1940’s, but recent studies have shown that people have become much worse at exercising self-discipline. This is no surprise to students of God’s Word because the Bible foretold that one evidence that we are living in “the last days” is that men would be “without self-control.”—2 Tim. 3:1-3."
Does anyone know what studies is referred to, because I can't find anything...