For Innovation, it takes 2 kinds of employees - written by Mark Watson, this short article talks briefly about the 2 different types of people necessary for Innovation: Ideation people and Execution People.
""Ideation" people create a multitude of ideas, want to try them out, learn by doing, and ask questions such as "what if?" and "can it be done?"
"Execution" people look for clear definitions of requirements, want to "do it right the first time" and eliminate less than satisfactory approaches. Their questions tend to be "Should we do it?" rather than "Can we do it?""
An interesting thought that would seem to imply that someone can't be both - but if taken in a slightly different way that would instead say that people have 2 different hats to put on during the innovation process - that of Ideation and Execution - would definately ring true.