We Homo sapiens often like to champion ourselves as the most intelligent species. In fact by all known metrics of intelligence, we are. However as whole, our species doesn't act intelligent. Take Creationism for example. It is a sad indictment of the intelligence of our species when educated people who in other aspects of life are 'smart', yet still manage to accept something so vapid, so devoid of truth of which all evidence points to the contrary as true. This phenomena itself is clearly evidence of evolution. No intelligent creator would craft a brain that so easily deludes itself into believing things as stupid as creationism.
This doesn't mean I think all creationists are stupid though, they simply have a faulty brain. We all do. I once was a creationist because I was led to believe it as a child by adults who didn't know any better. When I learned more about it I rejected it, but for a number of years, I looked at the evidence and rejected it, opting instead for a position of faith. Some people may never end up giving up cretinous beliefs and it is sad to realise this. Humanity is not as smart as we delude ourselves to believe. Sometimes, some people are smart at some things, but in general, we are not so smart.