Fixation
This term has several different meanings in psychology. Fixation has a long history in Freudian and clinical psychology, and refers to when a person is "stuck" in one stage of psychosexual development. For example, if a person does not get through the oral stage of development properly, then Freud would say that the person is fixated in the oral stage and will continue to seek oral pleasures, and will not be able to progress to the next stage of development until the oral issues are resolved. Fixation also refers to an inability to adopt any different or new perspective on a problem. It is similar to fixation in the Freudian sense except that here it is not necessarily referring to psychosexual development.