Research evidence points towards a middle position, and it is now generally accepted that there is a degree of modularity in aspects of brain organisation.
Deductive reasoning, on the other hand, has been shown to be related to either visual or linguistic processing, depending on the task; although there are also aspects that differ from them.
The brain is usually capable of learning new skills in the aforementioned areas, typically in early childhood, and of developing personal thoughts and beliefs about the world.
Old age and disease may affect cognitive functioning, causing memory loss and trouble thinking of the right words while speaking or writing ("drawing a blank").
Multiple sclerosis (MS), for example, can eventually cause memory loss, an inability to grasp new concepts or information, and depleted verbal fluency.