The Clan's reluctance to change is depicted by Auel as a function of their cognition; they are presented as dependent upon their racial-genetic memory. The average Clan child needs only be" 'reminded' "of a thing to know it permanently, though skilled tasks still require repetitive practice. Furthermore, the need to encode "everything" into a child's brain has increased the average Neanderthal head size to the point that, by the time of the first novel, women of the Clan are having trouble giving birth to their large-headed babies—a sign that their evolutionary strategy has run its course.