Recently I was reading a book entitled "50 Tips to Read People’s Mind". Somewhere in the book, the writer says:
These men do the seemingly impossible when they appear to be reading people's minds, often to a point of exactitude that confuses and even frightens.
I've always had problems with plural possessive nouns! I know this question might seem repetitive, but the answers I've found for similar questions were never satisfactory to me, especially when I came across this particular example. Why did the writer in the example above use both "people's mind" and "people's minds"? How are they different?
I know it's more common to say "reading people's minds" than "reading people's mind", but a search on google news and google books shows that the latter is not uncommon at all.