To get where it is, the brain has made some fascinating design decisions. The layering of systems has produced a complex environment, with automatic and controlled highly mixed. This development over biological time has introduced constraints. As has the architecture–it takes time for slow signals to make their way from one area to another. And there are computational difficulties too: How much of its capabilities can the brain afford to invoke when a sub-second response is required? The tricks used leave traces. There are holes in our visual field that we continually cover up. There are certain sensory inputs that grab our attention faster and more thoroughly than we’d expect.
(via Dehiscence ).