The evolution of spiral galaxies is far from being completely understood, especially in terms of internal secular evolution. To address this problem, we combine the kinematics and stellar population parameters extracted from long slit spectra of major and minor axis of six galaxies in order to disentangle disk heating agents. Including arm class and molecular gas surface density measurements we conclude that spiral structure could be the major driver for radial heating mechanisms. However, scattering by giant molecular clouds cannot be ruled out as a three-dimensional agent.