Domain-general v domain-specific mechanisms in intelligence and learning

I have often referred to the human brain clock as representing a domain-general cognitive mechanism, in contrast to a domain-specific mechanism.  I recently found an excellent article that describes the fundamental difference between "jack-of-all-trade" (domain-general) and compartmentalized or modular (domain-specific) brain-based cognitive mechanisms, placed within the context of evoultionary psychology.  Both classess of mechanisms are important for human cognition and learning.  For those who really want to understand this distinction, I would recommend the 2005 article "The evolution of domain-general mechnaisms in intelligence and learning" (Journal of General Psychology (by Chiappe & McDonald).