Well I think it had something to do with the scientist. He later had a conversation with the turtles that he manipulated their development when exposed to the ooze. If he hadn't, I believe they would have developed very much like the turtles with the blend of attachment to their first person they encountered (which DID happen) but also they would have had a higher mental development and not be as easily tricked.

Still that begs the questions as to why Splinter gained mostly mental prowess and not a more balanced approach as the turtles since both were covered with ooze from the same canister.