This file contains two separate datasets. "Raw data" contains participants' performances on the Simon task before any preparation. Reaction times (ms) and response accuracy on the Simon task are reported for each trial and each participant from the late-life depression and healthy control groups. The congruencies of the actual and preceding trials are specified. "Clinical and neuropsychological data" contains for each subject: clinical scores (depression, apathy, anxiety and impulsivity), neuropsychological scores (Moca, Stroop task, TMT, WCST, CPT-3) and mean performance on the computational Simon task.