The Milky Way's thick disk was originally identified by fitting the vertical density distribution of stars to a double exponential profile. Recent investigations have shown that, in addition to being older, thick disk stars show chemical and kinematical properties distinct from the thin disk. Most scenarios of thick disk formation discussed to date emphasize mergers, e.g., heating of a pre-existing thin disk, accretion of stars from disrupted satellites, or in-situ formation induced by infalling gas-rich systems. Recently, however, growing observational and theoretical evidence has suggested that the thick disk might be the result of the cumulative radial migration of disk stars over the history of the Galaxy. According to these models, disk stars move radially over their lifetimes, spreading the chemical signatures associated with their birth place at a range of galactocentric distances and giving rise to chemical and kinematical signatures corresponding to the common thin and thick disk divisions. In this study we search for observational signatures of radial mixing in the disk populations based on a large sample of F-and G-type dwarfs observed by SEGUE-1, divided into thin and thick disk populations characterized by low (-0.1 <[α/Fe] < +0.2) and high (+0.3 < [α/Fe] < +0.6) α-abundances, respectively. We also demonstrate that we are able to determine [α/Fe] with an accuracy of < 0.1 dex down to S/N = 20/1 for the SEGUE stellar spectra. This work was supported in part by grants PHY 02-16783 and PHY 08-22648: Physics Frontiers Center / Joint Institute for Nuclear Astrophysics (JINA), awarded by the U.S. National Science Foundation.