In the Harry Potter world, we see many forms of continuation beyond death -- ghosts, portraits, and even newspaper clippings appear to retain some part of the personality of the original person. However, they all appear to be mere echoes of the original. Despite this, ghosts and portraits continue to learn and act as the original, and thus may be considered indistringuishable from the outside.
Enter the Resurrection Stone. This Hallow supposedly brings back the souls of the dead, allowing discussion (and tearful moments for our hero, who then... purposefully loses it in a forest).
However realistic these spirits are, they don't appear to have any special features that differentiate them from the other magical constructs, so how does one know that they are the actual, unique soul of the original person? Granted the nature of the Hallows -- being either unique artifacts of unique power, or merely super well enchanted items with standard powers, it would be fitting for the "spirits" to merely be duplicates, as in the case of paintings and ghosts.
Is there any proof (via word of god, most likely) that the Resurrection Stone actually brings back the actual spirit of the person called?