The atomic motions in crystals are correlated. In this paper we demonstrate that information about the correlated motion of atoms, and consequently about the bonding within the crystal, can be obtained by analyzing the peak width of the atomic pair distribution function (PDF). We have measured the PDFs of Ni and InAs using synchrotron X-ray diffraction. The analysis of the Ni data allowed us to determine the Debye temperature which is in good agreement with values found in the literature. In contrast to the isotropic metallic bonding in Ni resulting in a relatively weak correlation between the motion of neighboring atoms, we found a very strong correlation in InAs as one might expect from the covalent bond between In and As. The results are compared with theoretical predictions by Chung and Thorpe (Phys. Rev. B 1977, 55, 1545).