A data nodule was a small device which apparently could store not only the experience, but also the entire identity of someone, and transfer them to a droid, temporarily giving the droid the skills and personality stored within. Once the nodule was removed, the droid would revert back to its original programming and personality, and would have no memory of events transpired while the nodule was active.

C-3PO was once under the influence of a data nodule containing the personality of Raymus Antilles, giving the protocol droid the skills necessary to save a rebel freighter from a band of space pirates.