I'm not a mind reader, so I can't know the exact motivations or thoughts of the doctor in question. However, I can offer some historical context on why this practice may have occurred forty years ago.
In the past, it was a common belief among some medical professionals that a newborn baby should cry immediately after birth as a sign of healthy lung function and responsiveness. The act of spanking or slapping the baby's bottom was believed to stimulate crying and ensure the baby's airways were clear. This practice was often thought to be a way to help the baby take their first breath and to establish that the baby was indeed breathing properly.
It's important to note that medical practices and knowledge have evolved significantly over the years. Today, this approach is considered outdated, and the standard practice in modern medicine is to provide immediate and gentle care to newborns, promoting skin-to-skin contact with the mother and supporting a calm and comfortable transition into the world.
If you have concerns or questions about past medical practices or events, it's essential to discuss them with a qualified medical professional who can provide accurate information and context.