How did we learn to think?

I've been thinking of this recently, as I came across and signed on for 10 free lessons on thinking. Every day for the last 10 days, an email has arrived with a link to a key question and a forum to post replies. I've worked through three questions to date and haven't yet replied to the fourth, as I'm still contemplating it. Through the lessons and website, there's access to interesting articles on brain wiring and other associated topics…so far, it's interesting and definitely something to think about!