Psychologists today consider this classical form of behaviorism to be "wrong" in the sense that modern cognitive research has clearly demonstrated the role of mental processes in psychology. A famous, but gruesome line of experimentation by noted psychologist Martin Seligman demonstrated behaviorism inability to explain learned helplessness. Dogs, which had previously been placed in cages with fully electrified floors, later never bothered to discover that newer cages they were placed in had a non-electrified section (separated by a short 'wall' that control dogs had no difficulty hopping).