It's about balance though, isn't it?
Research has the advantage that it looks at 1000s of babies, so can pick up subtle differences that you wouldn't see by looking at, say, 9 or 10 babies (your own and your sisters' or friends').
"Common sense" has the advantage that it's practical and based on the baby you know better than anyone else in the world.
But both have disadvantages too, eg it can be hard to know how to apply a general point (from research) to an individual baby, and research can be misleading if it's badly done.
Equally, sometimes "common sense" is just plain wrong. Think of all those babies in the past who were tightly bandaged and swaddled because it was believed that their arms and legs would grow crooked if they were allowed to wave them around! It seems ridiculous to us - but it was common sense for hundreds and hundreds of years.
Who knows what future generations will think of our common sense practices?? I often wonder what the recommendations for babies will be, by the time my dd (5 and a half months) has her own. Am bracing myself to be told that everything I did was wrong....
Anyway, it seems to me that the great challenge of parenthood is in being able to balance the different influences - the recommendations which come out of research, and your own feelings about what is best for your child - without getting too dogmatic at either extreme.
Sorry, didn't mean to write an essay there! Just got on a roll, as this issue has been trundling around my brain in the last few weeks. I will stop philosophising now