Biggest brains proportionally out of all animals. Certain regions more developed than others, in this case the frontal lobe in most regards to motor control, decision making. Fine tuned motor controls allowed for the use and development of tools. Has become more robust as well to support the weight of the upper body. Narrow pelvis and bigger brain makes it more difficult for birth. This is a dramatic difference between human and other primates. Head is widest part of birth and is most likely the place to get stuck. In terms of selective pressures, those who had difficulty with birth would die and so would baby. Brains are relatively underdeveloped at birth simply so the head is small enough to come out of pelvic girdle. Allows for easier passage of head during birth. Anterior fontanel is the (cid:498)soft spot(cid:499) typically lasts for a few hours. Babies are sometimes born with a slightly different shaped head, this.