We analyze age-velocity dispersion relations (AVRs) from kinematics of individual stars in eight Local Group galaxies ranging in mass from Carina (M_{*} \sim 10^{6}) to M31 (M_{*} \sim 10^{11}). Observationally the \sigma vs. stellar age trends can be interpreted as dynamical heating of the stars by GMCs, bars/spiral arms, or... Show more