"Parents who yell at their adolescent children for misbehaving can cause some of the same problems as hitting them would, including increased risk of depression and aggressive behavior, according to a new study." Andrea Petersen, THE WALL STREET JOURNAL, September 4, 2013
Intuitively, we in the communications business knew that harsh language was, at best, ineffective in modifying behavior. At worst, it broke the spirit of those on the receiving end of the "yelling" or hostile comments. Now, research backs that up.
In the journal CHILD DEVELOPMENT, there is a study by those at the Universities of Pittsburgh and Michigan, including professor Ming-Te Wang, which confirms that abusive language by parents harms adolescents. This can have profound implications for those who deal with young people. For example, the sports coach has been given license to berate mediocre performance. That was viewed as developmental. Maybe what it is developing is wounded youth.
In speechwriting, we might consider encouraging speakers to be respectful of audiences. Chiding them for supposed misdeeds, like not being creative enough, might be counterproductive.