The field of psychology may have grown to be respected as a science. Objectivity and the scientific method are both part of the psychologist's mode of operation. However, even the greatest of psychologists can only theorize about what makes human beings act the way they do. Absolutes are not part of psychology . Everything is relative and open to speculation. Theorists give us their views or ideas about life. In the field of psychology, there have been many different areas of interest. Human development is one of the most popular areas of interest for those who study psychology. Freud, Erikson and Piaget are all great theorists with different ideas concerning human development. Each theorist developed ideas and stages for human development. Their theories on human development had human beings passing through different stages. Each theory differed on what these stages were. These theories also differed with their respect towards paradigmatic assumptions, learning and development, and relationship towards educational practice. Freud is known as the father of psychology. Although some of his work has been dismissed, most of it still holds weight in the world of psychology. Freud believed that human development was fueled by inner forces. He believed the most powerful of all inner forces was our sexual being. Freud linked everything with sex. This includes any bodily pleasure whatsoever. Thus, when Freud discusses the sexual needs of children, they are not the same kind of sexual needs that an adult would experience. Children experienced sexual gratification in different ways. Sucking their thumbs or retaining their excrement could be seen as sexual gratification for small children. Freud also specified certain areas of our body as erogenous zones. Those areas included the mouth and genitals. This all fit in to Freud's obsession with sex. An obsession that could be linked to the era that Freud lived in. It was a very conservative period in history. Sexual feelings were often repressed. Freud's theory on human development could be labeled the psychosexual stages of development. Freud believed human beings passed through different stages in their life based on which part of their body gave them sexual gratification. Freud's psychosexual stages of development are five in total. The Oral stage takes place from birth to about one year. During this stage, a child is orally oriented. The mouth is the child's erogenous zone. Everything a child touches is put in his mouth. Freud believes children do this because it gives them pleasure. When a child sucks his thumb, it does so because it gives it gives him gratification. According to Freud, the gratification is sexual. The second stage in Freud's psychosexual development theory takes place between the ages of two and three years of age. The erogenous zone shifts location, thus moving from one stage to another. The second erogenous zone in Freud's stages of human development is the anal region. Freud believes children experience sexual gratification during bowel movements and when they withhold bowel movements. Some children may even experience pleasure handling, looking at, or thinking about their own feces. Once the Anal stage of development has been completed, the next stage of development for Freud is the Phallic Stage. This usually occurs at about three years of age. The shift in erogenous zones moves from the anal region to the genital organs. This stage is also known as the Oedipal Stage of psychosexual development. This name comes from the legendary king, Oedipus, who killed his father and married his mother. During this stage children take interest in their sexual organs. Soon they notice differences and similarities between themselves and their parents. Each sex wants to be with the parent of the other sex, for girls this is referred to as the Elektra complex. Once the children realize they cannot be with their mother or father, they identify with the parent of the same sex. The next stage is called the stage of Latency. This stage is characterized by a lack of change or absence of erogenous zones. After the realization that the child cannot be with a parent sexually, the child shifts its attention to same-sexed relationships. Boys will shift their sexual urges and drives to something acceptable, such as sports. This is a time of relative calm. The last stage of Freud's psychosexual development is the Genital Stage. The erogenous zone returns in a very powerful way in the genital organs. This stage takes place from puberty into adulthood. This stage is marked by true sexual desire and sexual relationships. Erikson took Freud's ideas and enhanced them. He added stages for the adult years. He also shifted his attention to identity rather than sexuality. Erikson developed the psychosocial stages of development. He is known for his eight stages of life. Erikson's first stage is during infancy. It deals with trust versus mistrust. The child develops an outlook on life and whether the world can be trusted or not. The child develops trust if the parents give the child something it can rely on. The child develops a sense of optimism or pessimism during this stage. according to Erikson. The next stage in Erikson's psychosocial development is during early childhood and is known as autonomy versus shame and doubt. The child becomes autonomous and realizes he can say yes or no. This stage will determine whether or not a child develops a sense of self-certainty. Erikson's next stage takes place during the ages of three to six years. This stage is marked by initiative versus guilt. This stage is important in developing the child's sense of enterprise. The child develops initiative when trying out new things and is not scared of failing. The fourth stage of Erikson's developmental theory takes place at about six years of age and lasts till puberty. This stage deals with industry versus inferiority. The child learns skills of the culture and must deal with feelings of inferiority. Adolescence brings about the next stage for Erikson. This stage is known for identity versus identity confusion. During this stage, Erikson believes adolescents must develop a sense of self and who they are. They develop a sense of identity. The sixth stage for Erikson is known for intimacy versus isolation. This stage takes place during young adulthood. The person seeks commitments from others. If he is unsuccessful, he may take on isolation. Erikson believes this stage is important in learning love. The seventh stage for Erikson takes place during adulthood. It is marked by generatively versus stagnation. During this stage, the adult is concerned with guiding the next generation. This stage according to Erikson gives the adult a sense of caring. Erikson's last and eighth stage takes place at a mature age. Old age is marked by integrity versus despair. During this time, the person may achieve a sense of acceptance of their own life, which in turn allows for the acceptance of death. When one passes through this last stage, Erikson believes that a person has achieved wisdom. Piaget also believed in developmental theory. Her stages were cognitive stages. These stages were based on what the child can do. According to Piaget a child passes through four stages in its life. Piaget was interested in the child's abilities and senses, not sexual desires like Freud was. Piaget believes the first stage of development should be a cognitive one. Her first stage is known as the sensor motor stage. It takes place from birth to about two years of age. During this time a child learns motor meaning, object permanence, and Th. beginning of symbolic representation, also known as language. The child will change from someone who responds only through reflexes to one who can organize his activities in relation to his environment. It does this through sensory and motor activity. The next stage in Piaget's cognitive development theory is the preoperational stage. This takes place from about two to seven years of age. During this stage the child's language develops. He develops a representational system and uses symbols such as words to represent people, places, and events. From about the ages of seven to thirteen, Piaget believes children enter the concrete operational stage. They can solve problems logically. They can understand rules and form concepts. Some children become moralistic. The last stage Piaget believes is the formal operational stage. This stage takes place from about twelve years of age through adulthood. Once someone has reached this stage, one should be able to think abstractly, manipulate abstract concepts, use hypothetical reasoning, and use creative language. Someone should be able to think about the possibilities. These three theories on human development each have their own good points and bad points. One problem all theories must deal with are paradigmatic assumptions. These are ideas that the theorist has taken for granted as facts. An example is Freud's notion that women suffer from a lack of self esteem or self worth all their lives because of penis envy. Freud's assumption could have been a product of the times he lived in. It was a time when women were treated as second class citizens. Today, the idea of penis envy has lost its worth. Freud's assumption that sex is the driving force behind everything could also be a product of his times. Sexual feelings were often repressed. The problem with paradigmatic assumptions is that each person grows up in a different culture and some theories don't apply to everyone. The problem with psychology remains that it is not an exact science. It is difficult to develop good paradigmatic assumptions because of that. Erikson assumes a child must learn these virtues or skills in this order. But, what if a child does not? Someone may never has a meaningful relationship, but they may develop wisdom. This would undercut Erikson's assumptions that everyone must pass through these stages in this order. Piaget also has some assumptions in her theory. A man who never learns to add, may be able to think hypothetically. These mistakes only show that psychology still has its flaws. Each of these theories has some value because they are not totally wrong. These theories have withstood criticism and are some of the best. Each theory is similar in its time table and sequence of life events. Where they differ is in their focus. Freud focuses on sex, Erikson focuses on the self and social orientation, and Piaget focuses on the child's ability and senses. Each theory is also useful when applied to its relationship to educational practice. Each theory guides a teacher in trying to understand.