We investigated the orbital-spin coupling in rare-earth titanates with a perovskite structure using strain measurements. The anisotropic strain that appears with magnetic ordering or an applied magnetic field is dominated by the pair correlation of the Ti spins coupled with the orbital degree of freedom. We found that such anisotropic strain also emerges with the evolution of magnetic and orbital correlations in the critical region near the antiferromagnetic-ferromagnetic phase boundary, where long-range ordering does not occur.