The discussion in chapter two has drawn attention to the way an initial increase in brain capacity in proportion to body size may have arisen. However, notwithstanding this possibility, it remains the case that the emergence of specific enhanced cognitive abilities occurred by way of natural selection. As was discussed previously, even the development of neural inputs and outputs occurs competitively in a selective environment. Hence, although the volume of certain areas of the brain may have increased relative to the normative demands of a hominid body non-adaptively, the new functions which subsequently arose would have done so by way of natural selection: that is, through competition with other possible novel inputs and outputs. From what is already known about neural developmental processes from findings in evolutionary neuroscience by such as those of Edelman and Deacon, once spare neural capacity emerged competition would have set the context for any restructuring of hominid mental life that subsequently took place. In circumstances defined by competition in biological systems, those traits or functions that succeeded would have been those that best enhanced either survival and reproduction. In these cases, no other explanation is needed, this is the standard Darwinian position on natural selection, but, of course, more is needed to establish this argument than a mere assertion. If it is the case that the characteristics of human cognition are adaptive, then it should be possible to outline the process through which the cognitive life of modern humans arose. So why did symbolic reasoning emerge from the expansion of cranial capacity outlined in chapter two instead of, say, enhanced audio abilities as with dolphins and other cetaceans? Well, it must have something to do with the context of early hominid life. Something that led to an advantage being gained by those early ancestors that first displayed an ability to think abstractly.