When anxiety occurs, the mind's first response is to seek rational ways of escaping the situation by increasing problem-solving efforts, and a range of defense mechanisms may be triggered. These are ways that the ego develops to help deal with the id and the superego. Defense mechanisms often appear unconsciously and tend to distort or falsify reality. When the distortion of reality occurs, there is a change in perception which allows for a lessening in anxiety resulting in a reduction of tension one experiences. Sigmund Freud noted a number of ego defenses which were noted throughout his work. His daughter, Anna Freud, developed and elaborated on them. The defense mechanisms are as follows: