This image is from an Israeli art history blog showing the development towards naturalism in Greek Sculpture. Here is a translation of the text.
One can also see in the sculptures how the statue's proportions improved over time. The head gradually became smaller and more realistic. The chin was initially very prominent but over time became more realistic. There is a process towards a more realistic expression. Proportions were not too accurate in the early sculptures. The hands over time begin to be less close to the body. You can see the tendons on the foot employed to show movement, giving a more dynamic sculpture. Neck width is also variable and will be less thick. Hair begins to loosen the Egyptian tradition of long braided. Towards the end of the period the hair has a more realistic form as it was in Greece. Again there is emphasis on anatomical accuracy. A hypothesis is that the Olympics, were held naked in the same period and allowed a more accurate study of the human form.
The Greek Body
Understanding Greek Sculpture: Ancient Meanings, Modern Readings