TheThe development of cognitive traits in humans is the focus of immense research activity, especially in neurobehavioral and brain imaging studies.  However, corollary interest in the predisposition of select areas in neocortex to perform specific cognitive functions has been hampered by the lack of comprehensive histological data on humans to complement non-invasive brain imaging data.  Here, we reanalyze JL Conel's (1939-1967)[i] uniquely comprehensive study of postnatal development in the human neocortex.  We quantify changes to relative neuron population distributions between observation ages as well as the cumulative changes from birth through six years of age across the entire neocortex.  Our new analysis supports the existence of 1) a developmental "clock" for the human neocortex, 2) differential area/layer combination responses to the "clock", 3) clock-linkage by layer, and 4) distinctive Layer IV neurodevelopment within this developmental laminar pattern.