We explore possible correlations between the light profile shapes of early-type galaxies, as parameterized by the Sérsic index $n$, and relevant stellar population parameters, which were obtained from spectra of extremely high signal–to–noise and stellar population models that provide an age indicator that is virtually free of the effects of metallicity. We do not find any robust correlation between $n$ and mean age or metallicity. However, we find evidence for a strong positive correlation between $n$ and [Mg/Fe] abundance ratio. We speculate that early-type galaxies settle up their structure on short time-scales in agreement with those imposed by their [Mg/Fe] ratios, suggesting that the global structure was already at place at high $z$.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html