The Divided Brain and the Search for Meaning

by Iain McGilchrist

The left hemisphere is especially good at voluntary and social expressions of emotion and one of the most clearly lateralised emotional registers is that of anger, which lateralises to the left hemisphere. Deeper and more complex expressions of emotion, and the reading of faces, are best dealt with, however, by the right hemisphere. As far as reason goes, the left hemisphere is better at carrying out certain procedures that involve manipulating numbers, but has less of a grasp than the right hemisphere of what those numbers mean. Much of mathematics is dependent on the right hemisphere: most of its great discoveries were perceived as complex patterns of relationships, and only later, often much later, translated painstakingly into linear sets of propositions. Deductive logic, it turns out, depends on the right hemisphere.