Observed axis ratio, q, as a function of redshift for galaxies from the morphological sample (black points) after removing bulge-dominated galaxies and those with small disk sizes. The median values for the six most edge-on galaxies in redshift bins of width Δz = 0.15 are shown as red squares. The red line represents the thickness prescription that was applied. Independently of mass, galaxies tend to have thinner disks at larger redshifts, which may be due to the fact that we probe younger stellar populations at higher redshifts when observing in a single band.