Psychology

Lifespan can be defined as the period that extends from conception to death. Thus, lifespan development is a process that begins at conception and continuous to death. Lifespan development can therefore be defined as a methodical, intra-individual transformation that is attributed to progressions corresponding to age. The development advances in a way that implicates the level of functioning. As a child grows he exhibits transformations that progresses with time. These may include physical growth, cognitive advancement, and psychological advancement that may entail emotional and social development.

Physical development may directly refer to the increase in body and organ sizes, signs of ageing and motor abilities. Cognitive development is mainly concerned with the manner in which a child thinks or perceives the world. This is brought about by the changes in perception, language knowledge, memory, and problem solving skills. Psychological development entails transformations in personal and interpersonal advancements that are concerned with emotional and social aspects. Emotional development subjects children to certain emotional feelings such as guilt and pride. Social development is mainly concerned with the manner in which children interact, share and relate as friends (Hernandez, 2008).

Characteristics of lifespan perspective
Development is a distinctive feature that largely varies from individual to individual. Life expectancy has been greatly boosted by progress made in nutrition, health and medical knowledge. Development is life-long and thus is not dominated by any age period, it is multi-dimensional. This is because it is concerned with the biological, cognitive, socio-emotional and spiritual aspects. Development can also be said to be multidirectional as some features of development increase while others are decreasing. Another characteristic of development is that it is plastic. It is able to assume different paths depending on the living conditions of an individual. It has the capacity to change. For example, the condition of a child experiencing intellectual retardation may be reversed by the administration of proper diet and positive experience (Hernandez, 2008).

The other characteristic is that development is historically-embedded. This is to mean that historical conditions can influence development. Development is multidisciplinary. Professionals in the field of psychology, sociology, anthropology, neuroscience and medical research are all concerned with human development with a common goal of expanding their understanding of development in the course of the lifespan. It is contextual in the sense that a person incessantly responds to and acts on context. Such contexts may include the biological constitution of an individual, physical environment, and social, historical, and cultural contexts (Hernandez, 2008).

Human Development Domains and Periods
Development domains are categories that are adopted by scientists. Three main domains have been defined and they appear to be related or they appear to affect each other. These domains are biological, cognitive and psychological. Biological domain is characterized by human growth and physical changes in human. This is normally centered on the course of childhood and adolescence. It is normally concerned with maturation and growth. Cognitive domain tends to address the manner by which learning takes place and the reasons for deterioration of memory in the course of old age. Cognitive domain is constituted by the mental processes of imaging, perceiving, way of thinking and problem solving. Psychological domain is concerned with emotions, individuality and social relations and expectations. All these domains appear to be operating jointly and affect each other (Boyd & Bee, 2006).

Human development periods cover the lifetime from conception to death. In total there are eight major periods. These periods include infancy and toddler, early childhood, middle childhood, adolescence, early adulthood, middle adulthood, and late adulthood. As long as a person is alive, he/she will pass through each of these stages. In the course of growth of a newborn to a toddler, they portray a characteristic thinking ability, language and personality. In their middle years, great emphasis is laid on family, school, friends in addition to individuality and cognitive skills. When one moves from childhood to adulthood, sexual development is exhibited and the individual is subject to thinking about marriage and career. In adulthood, one cannot avoid thinking about retirement. Theories have been put forward to explain in details how the actual transitions from one period to another occur. Some of these theories include the psychoanalytic, learning and cognitive theories (Boyd & Bee, 2006).

Contemporary Concerns in Lifespan Development
There are two main concerns that are related to lifespan development. These are nature and nurture, and continuity and discontinuity. For the better part of history, researchers thought that transformations in human were due to forces that could have been external or internal. Advancements in the knowledge and experimental factors of biological processes are referred to as nature versus nurture. Proponents of nature harbor the belief that children are born with certain traits that are innate and are inborn biases. These may have arisen as a result of genetics or as a consequence of prenatal environment. In any case children are not born as blank slates. Proponents of nurture argue that the outcomes of certain occurrences depend on how an individual perceive them (Boyd & Bee, 2006).

In the case of continuity and discontinuity, the subject of contention is whether the transformation that comes with age is basically a matter of amount, degree, type, or kind. The number of friends that a child has may vary as his age advances. These changes that come with age can be grouped as universal, group specific and individual changes. Children normally advance slowly through the various stages of cognitive development. There is a possibility of intelligence and individuality in the course of childhood merging at the onset of adulthood. This continuity is not rigid but flexible hence it is subject to change. A child who portrays a high level of intellectual capacity in the course of his childhood may lose this good trait if they are continuously subjected to an environment where they are vulnerable to abuse and are neglected (Boyd & Bee, 2006).

Every human being goes through universal changes. Such changes are a characteristic of certain ages. Group specific changes are a preserve of individuals who share comparable cultural and historical experiences. Individual changes are limited to the person concerned and are attributed to genetic factors and timing of experiences. Everybody is unique, and this is attributed to their genes which dictate their physical appearance, individuality, and intelligence (Smith, 1999).

Conclusion
Development of the lifespan is a matter that begun a long time ago but is still an area that enjoys social and scientific research. Children are normally born, and they grow to develop their understanding and perception of their environment. We realize that lifespan is multidimensional, life-long, multidirectional, plastic, historically-embedded, multidisciplinary and contextual. The major human domains are biological, cognitive and psychological. Lifespan development can be divided into eight major periods that range from infancy to late adulthood. With the expansion of the field, controversies surrounding nature versus nurture and continuity versus discontinuity become more complicated.