Dogs that couldn't escape a shock later stopped trying, even when they easily could
Martin Seligman and Steven Maier gave dogs mild shocks they had no way to stop, then later put them in a box where jumping over a low barrier would end the shock. The dogs that had learned nothing could stop the earlier shocks simply lay down and endured it, even though escape was now trivially easy. The finding reshaped how psychologists understand depression as a learned sense that nothing you do matters.