Agony seats were a form of torture created by the Kaleds. Davros used one on the Fourth Doctor, Sarah Jane Smith and Harry Sullivan, whom had travelled back to interfere with his creation of the Daleks, to extract information about all future Dalek victories and defeats. (TV: Genesis of the Daleks)
The Seventh Doctor was placed in an agony seat in order to extract all of his victories so the Daleks could undo them. (AUDIO: Daleks Among Us)