  We have analyzed multi-passband photometric observations, obtained with the
{\it Hubble Space Telescope}, of the massive ($1.8 \times 10^5 M_\odot$),
intermediate-age (1.8 Gyr-old) Large Magellanic Cloud star cluster NGC 1783.
The morphology of the cluster's red giant branch does not exhibit a clear
broadening beyond its intrinsic width; the observed width is consistent with
that owing to photometric uncertainties alone and independent of our
photometric selection boundaries applied to obtain our sample of red-giant
stars. The color dispersion of the cluster's red-giant stars around the
best-fitting ridgeline is $0.062 \pm 0.009$ mag, which is equivalent to the
width of $0.080 \pm 0.001$ mag derived from artificial simple stellar
population tests, that is, tests based on single-age, single-metallicity
stellar populations. NGC 1783 is comparably massive as other star clusters that
show clear evidence of multiple stellar populations. After incorporating
mass-loss recipes from its current age of 1.8 Gyr to an age of 6 Gyr, NGC 1783
is expected to remain as massive as some other clusters that host clear
multiple populations at these intermediate ages. If we were to assume that mass
is an important driver of multiple population formation, then NGC 1783 should
have exhibited clear evidence of chemical abundance variations. However, our
results support the absence of any chemical abundance variations in NGC 1783.
