Final answer:
Neanderthals had a larger average brain size than modern humans, but intelligence is not solely determined by brain size. Neanderthals had different brain organization and development, with less emphasis on speech and language regions and more emphasis on sensory areas. This adaptation may have helped them survive in challenging hunting conditions.
Step-by-step explanation:
Neanderthals had a larger average brain size compared to modern humans, with a size of 1,520 cc compared to modern humans' 1,200-1,400 cc.
However, brain size alone does not determine intelligence. The organization and development of different brain areas play a crucial role.
Neanderthals had less developed frontal regions, which are associated with speech and language, but more developed back areas related to senses. This adaptation may have been beneficial for survival in harsh hunting conditions.