Beck Cognitive therapy is a psychotherapy developed by American pyschiatrist Aaron T. Beck. Cognitive therapy is one of the therapeutic approaches within the larger group of cognitive behavioural therapies. Cognitive therapy seeks to help the client overcome difficulties by identifying and changing dysfunctional thinking, behaviour and emotional responses. This involves helping clients develop skills for modifying beliefs, identifying distoed thinkings, relative to others in different ways and changing behaviours. Treatment is based on collaboration between client and therapist and on testing beliefs. Therapy may consist of testing the assumptions which one makes and identifying how some of one's usually unquestioned thoughts are distoed, unrealistic and unhelpful. Once, those thoughts have been challenged, ones feelings about the subject matter of those thoughts are more easily subject to change. Beck initially focussed on depression and developed a list of errors in thought that he proposed could maintain depression, including arbitrary inference, selective abstraction, over generalization and magnification (of negatives) and minimization (of positives). According to Beck's theorey of the etiology of depression, depressed people acquire a negative view of the world in childhood and adolescence. Children and adolescent who suffer from depression acquire this negative view earlier. Depressed people acquire such view through a loss of a parent, rejection by peers, (criticism from teachers or parents, the depressive attitude and other negative events). When the person with such view encounters a situation that resembles the original conditions of the learned view in some way, even remotely, the negative views of the persons are activated. A simple example may illustrate the principle of how cognitive therapy works Having made a mistake at work, a person may believe "I am useless and can't do anything right at work". Strongly believing this then tends to worsen his mood. The problem may be worsened fuher if the individual reacts by avoiding activities and then behaviourally confirming the negative belief to himself. As a result, any adaptive response and fuher constructive consequences become unlikely, which reinforces the original belief of being useless. In therapy, the latter example could be identified as a self fulfilling prophecy or "problem cycle" and the effos of the therapist and client would be directed at working together to change it.