There was a recent SMU study by George W. Holden. The website is: http://blog.smu.edu/research/2011/06/spanking_discipline_or_assault.html The research was originally intended to focus on parents yelling at children in their daily interactions. Mothers agreed to have audio recordings made of their evening activities with their children. The researchers analyzed the recordings and reported frequent incidents of corporal punishment that were concurrent with yelling and high levels of frustration from the mother. The majority of spankings appeared to be "knee-jerk" reactionary responses when parents were frustrated rather than thought out consequences for a previous behavior. There are really no reported examples of parents explaining to their child why they were getting a spanking before or after the swat(s). One parent is recorded spanking the child in response to being kicked by the child. This tit-for-tat, "let's see who is bigger and stronger" type of response