It has been suggested that Narrow-Line Seyfert 1 ( NLS1 ) galaxies are evolutionarily young objects , powered by the accretion of gas onto central black holes that are significantly lower in mass than those found in typical broad-line Seyferts .
We explore this hypothesis through the analysis of high-spatial resolution , near-IR imaging data obtained in J and K ^ { \prime } for a sample of 11 NLS1s .
Surface brightness profiles are separated into their constituent components using two-dimensional decomposition techniques .
By employing the correlation between black-hole mass and host galaxy bulge luminosity , calibrated for near-IR wavelengths using 2MASS data , we determine the mean black-hole mass for our sample to be , in solar units , \langle { log } ( M _ { BH } ) \rangle = 7.9 .
Using the correlation between the size of the broad-line region and the monochromatic continuum luminosity , we obtain black-hole mass estimates under the assumption that the emission-line gas is in virial equilibrium .
The mean black-hole mass derived from this relation is \langle { log } ( M _ { BH } ) \rangle = 6.4 .
It is found that the estimates obtained from the black-hole mass-bulge luminosity relation are systematically one full order of magnitude larger than those derived from the black-hole mass-broad-line region radius relation .
We explore possible causes for this discrepancy in M _ { BH } estimates and the ramifications for our understanding of the role played by NLS1s in AGN evolution .

Because numerical simulations constrain the start of the AGN duty cycle to a time shortly after a significant gravitational interaction , we examine the morphology and near-IR bulge colors of the NLS1 sample for evidence of recent encounters .
The mean bulge color is found to be \langle ( { \it J } - { \it K _ { s } } ) \rangle = +1.85 \pm 0.58 , which is redder than that of both a matched sample of non-active galaxies and published estimates for broad-line Seyferts .
The source of the unusual bulge colors may be an excess of flux , peaking at around 2.2 µm , that has been detected near the centers of some NLS1s such as Mrk 1239 .
No evidence is found for light asymmetries or an extra stellar component that would indicate NLS1s are young objects .
Finally , we postulate that there may be some interesting lines of circumstantial evidence suggesting that secular processes may be relevant in the evolution of NLS1s .