"Our small, weak jaw muscles are not adapted for chewing tough raw food, but they work well for soft, cooked food.Here you can see the anatomical difference in jaws and teeth between us and ancient members of our Family. (The author of this video states, "This is not meant to be an accurate representation of our own lineage."):
In nonhuman apes these muscles often reach all the way from the jaw to the top of the skull where they sometimes attach to a ridge of bone called the sagittal crest, whose only function is to accommodate the jaw muscles. In humans, by contrast, our jaw muscles normally reach barely halfway up the side of our heads.
If you clench and unclench your teeth and feel the side of your head, you have a good chance of being able to prove to yourself that you are not a gorilla: your temporalis muscle likely stops near the top of your ear."