Men komplekse dyr hadde oppnådd sin adaptive fleksibilitet til en viss pris-de hadde handlet en avhengighet for en annen. Det var ikke lenger nødvendig å endre kroppene sine for å tilpasse seg, for nå var tilpasningen deres atferd, sosialt bestemt. Den oppførselen krevde læring. På en måte ble tilpasningsdyktig egnethet ikke lenger overført til neste generasjon av DNA i det hele tatt. Det ble nå båret av undervisning.
(But complex animals had obtained their adaptive flexibility at some cost--they had traded one dependency for another. It was no longer necessary to change their bodies to adapt, because now their adaptation was behavior, socially determined. That behavior required learning. In a sense, among higher animals adaptive fitness was no longer transmitted to the next generation by DNA at all. It was now carried by teaching.)