Left panels: distribution of mean light-weighted [Fe/H] and [α/Fe] for the old vs. intermediate sub-populations. Galaxies in yellow are those where [Fe/H]_o< [Fe/H]_i−0.15 (SLF-ETGs), pink where [Fe/H]_o> [Fe/H]_i+0.15 (ACC-ETGs). Galaxies with uncertain classification are shown in black. Average uncertainties including all degeneracies are shown in the upper left corners. Right panels: age dependence of [Fe/H] and [α/Fe] within each galaxy, i.e. their enrichment history. Galaxies with uncertain classification have been omitted for clarity.