Learned helplessness is an important theory of psychology discovered by Dr. Martin E. P. Seligman. He set up an experiment with dogs who had been trained to expect a shock after hearing a tone (see Classical conditioning). Those dogs were placed in room where part of the floor was electrified and part was not. The dogs which had been conditioned to expect the shock made no effort to escape the shock even if it meant little effort. When subjected to adverse conditions for long enough an animal, or a human, stops fighting the conditions and just learns to live with them and will not try to overcome them because of the appearance of futility.
People who suffer from domestic violence, bullying, depression, drug abuse, and alcoholism often experience some level of learned helplessness. This may manifest in a feeling of worthlessness, guilt, embarrassment, powerlessness, and shame.
- "This theory, backed up by years of research, is that a great deal of depression grows out of a feeling of helplessness: the feeling that you cannot control your environment." 
- Learned Optimism