  We present mid-infrared spectra and photometry of thirteen redshift 0.4<z<1
dust-reddened quasars obtained with Spitzer IRS and MIPS. We compare properties
derived from their infrared spectral energy distributions (intrinsic AGN
luminosity and far-infrared luminosity from star formation) to the host
luminosities and morphologies from HST imaging, and black hole masses estimated
from optical and/or near-infrared spectroscopy. Our results are broadly
consistent with models in which most dust reddened quasars are an intermediate
phase between a merger-driven starburst triggering a completely obscured AGN,
and a normal, unreddened quasar. We find that many of our objects have high
accretion rates, close to the Eddington limit. These objects tend to fall below
the black hole mass -- bulge luminosity relation as defined by local galaxies,
whereas most of our low accretion rate objects are slightly above the local
relation, as typical for normal quasars at these redshifts. Our observations
are therefore most readily interpreted in a scenario in which galaxy stellar
mass growth occurs first by about a factor of three in each merger/starburst
event, followed sometime later by black hole growth by a similar amount. We do
not, however, see any direct evidence for quasar feedback affecting star
formation in our objects, for example in the form of a relationship between
accretion rate and star formation. Five of our objects, however, do show
evidence for outflows in the OIII 5007 Angstrom emission line profile,
suggesting that the quasar activity is driving thermal winds in at least some
members of our sample.
