It is possible that a number of people who do not recall being spanked as children or witnessing spanking may have had either experience during a period of their life when memory was not reliable or developed. How much of what happened to you at 3 do you remember specifically and accurately? Most of us also grew up in cultures where the threat of spanking certainly existed and there were many references to it on TV and other
There might be a scintilla of truth in that if CP or its lack thereof operated in a vacuum. It didn’t. Decrease in CP usage at school (if not so much at home) has occurred in a society where enormous other changes have also occurred relative to family stability, time spent by parents with children and in actively raising children, changes in societal values as a whole, increased mobility and the decrease of the availability of the nuclear family to help, gigantic increases in the divorce rate, etc, etc. etc.