Without these, it would be difficult, if not impossible, to detect a round object, like a baseball, hurdling toward you at 90 miles per hour. Many people believe that it is important to talk to the fetus to help foster attachment, and get the baby used to the sound of the parents voice. Others believe that this is not useful as the fetus can't hear. However, the reality is that the fetus is responsive to sound at approximately 6 months of 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. This type of schedule is called fixed because the amount time the organism must wait remains constant. In addition, the investigator can determine what NOT waiting will do. This type of schedule is called fixed because the number of operant responses required remains constant. It is like turning on a light.