No one draws pictures of heads with little gears or hydraulics inside any more. The modern conceptualization of the brain is firmly computational. The brain may be wet, squooshy, and easy to serve with an ice cream scooper, but it is nevertheless a computer. 


However, there is a rather blaring difficulty with this view, and it is encapsulated in the following question: If our brains are computers, why doesn’t size matter? In the real world of computers, bigger tends to mean smarter. But this is not the case for animals: bigger brains are not generally smarter. Most of the brain size differences across mammals seem to make no behavioral difference at all to the animal.