the frontal lobes (left and right) are situated at the "front" of the cortex, i.e. behind the forehead. They are the largest of the lobes in the cerebrum, and may be thought of as the "highest" part of our brain. The frontal lobes are critical for those faculties that humans regard as special to our species - reasoning, planning, attention, some aspects of language. Women have up to 15% more brain cell density in the frontal lobe, but with age, appear to shed cells more rapidly from this area than men. By old age, the density is similar for both sexes. The effect of this on performance is unknown.