Psychology

Human development starts with the brain development that begins with formation of neural tube and ends with myelination passing through important events that macroscopically proceed in sensomotor areas and cortex Progress in imaging technique and genomic research contributed to the deeper understanding of normal maturation of human brain (Marsh, Gerber  Peterson, 2008), allows exploring brain development in correlation with function and provides insights into ways cognitive abilities develop.

Developmental Timeline
Major life periods prenatal, infancy, early childhood, childhood, adolescence and adulthood as well as cognitive, psychosocial and moral development will be reviewed.

Prenatal development
The central nervous system starts developing in the human fetus beginning from week two to three by the folding and melting together the ectoderm and creating the neural tube (cited in Huttenlocher  Dabholkar, 1997). Neural tube closes at the end of fifth week and tissues of ectoderm start differentiating into predecessors of different future brain structures (cited in Levitt, 2003). Further major maturational events like birth and death of neurons, their migration, creation of complex arbors of axons and dendrons, myalination of axons take place. By the eighth week of gestation, stems cells in the proliferative zone differentiate into the location from which cortical and subcortical neurons will originate (cited in Molliver, Kostovic  van der Loos, 1973 cited in Pencea, et al., 2001 cited in Rakic, 1972) from week 20 sulci and gyri are becoming visible on MRI (cited in Huisman, et al., 2002).

Infancy
Brain development can be described by the rate of maturation of white matter of the cortex and increasing myelination of axons resulting in faster information processing. Better connectivity between different sites and is adding more fibers to white matter tracts (Paterson, Heim, Friedman, Choudhury  Benasich, 2006). From birth to the age of 1 to 3 months, myelinations starts in the basis of brain with the pons and the cerebellum peduncles going till corpus callosum at 6 months, anterior limb of internal capsule myalinates. Frontal, parietal and occipital lobes begin to myelinate at age of 8 to 12 months (cited in Paus, et al, 2000).

At infancy, cognitive development according Piaget is at the Sensorimotor stage that is marked by developing knowledge of the world and is based on physical experiences (Huitt  Hummel, 2003). At the end of this stage, some language abilities are developed.

Erikson (1968) describe this period as a stage of Trust vs Mistrust. Child begins to learn how to trust others and further starts developing confidence and security in surrounding world. If completed unsuccessfully this stage may end by developed anxiety and fear.

Emerging evidence from cognitive neuroscience and current possibility to visualize the living brain, show the correlation between brain structure and cognitive function (e.g. language, face processing and object permanence) across development (Paterson, et al., 2006). Results from studies show that areas responsible for face processing changes with age at first subcortical structures were recruited, later in the development (after 3months) more cortical structures were involved in this cognitive function (cited in de Haan, et al., 2001).

Early childhood
Brain development is characterized by the decrease in cortical grey matter and increase in white matter, showed by the data from neuroimaging studies (Giedd, et al, 1999).

According Piaget, it is a Pre-operational stage, in which children are using symbols, language is more mature, and imagination is very much developed (Huitt  Hummel, 2003).

According to Erikson (1968), the period between one to three years is the stage of Autonomy vs. Shame and Doubt. Children start to gain autonomy, making choices what to play, what toys to pick-up. Encouraged children are developing confident in themselves.

Childhood
This period is described by Piaget as Concrete operational stage, in which children use symbols systematically and logically and they are related to concrete objects. Operational thinking starts developing, egocentricity declines (Huitt  Hummel, 2003).

Psychosocial development is covered in the stage of Initiative vs. Guilt and the stage of Industry vs. Inferiority developed by Erikson (1968). From age three to six years, children are developing sense of initiative, start feeling secure in their ability to lead others and making decision if this period is suppressed, the sense of guilty may develop and children may further lack self-initiative and remain followers of others. From age six years to puberty, children develop sense of pride in their accomplishments and initiate activities themselves. Encouragement reinforces their confidence in ability to meet the goals.

According to the Kohlbergs theory of moral development, the period from one year to nine years is Preconventional Level of moral development and is at a stage of Self focused morality. Respecting rules defined by parents in order to avoid negative consequences, is the most characteristic behavior at this stage (Crain, 1985).

Adolescence
 Adolescence is a complex transition period between childhood and early adulthood and is characterized by considerable brain development, especially in frontal and parietal regions and presents decline in grey matter volume (Choudhury, Blakemore  Charman, 2006). Increase in the density of white matter of prefrontal cortex and parietal cortex is seen (Choudhury, Blakemore  Charman, 2006 Marsh, Gerber  Peterson, 2008). Data from behavioural and fMRI studies support the fact that development of executive function that ensure coordination and control of thoughts and behaviours continue to develop as well as other cognitive skills like processing speed, prospecting and working memory, decision-making and inhibitory control, which is an important characteristic of healthy psychological development. Children must learn to use inhibitory processes and to filter and arrange their thoughts, feelings, and behaviors based on social signals (Marsh, Gerber  Peterson, 2008).
This period and also adulthood is described by Piaget as Formal operational stage, which can be characterized by the development of abstract thinking and logical use of symbols related to abstract concept (Huitt  Hummel, 2003).

Adolescence is a period of identity formation (Klimstra, Hale III, Raaijmakers, Branje  Meeus, 2010), which was stressed by Erikson as the central task of adolescence (cited in Erikson, 1972, 1974). Klimstra and colleagues (2010) argue that identity formation happens from early adolescence through middle (cited in Meeus, 1996) to late adolescence (cited in Marcia, 1980 cited in Waterman, 1982, 1993).

Adulthood
Psychosocial development is covered in the three stages determined by Erikson (1968) Intimacy vs. Isolation stage, Generativity vs. Stagnation stage and Ego Integrity vs. Despair stage. Young adults are sharing themselves more intimately, explore relationship that lead to long-term commitment. Middle adulthood is characterized by established career, settled family life, participation and involvement in the community life. Late adulthood is characterized by contemplation and evaluation of the life accomplishments.

Moral development entered into Postconventional Level and is covered in the stage of Higher Focussed Morality stage by Kohlberg, is characterized by development of rules and norms that vary by groups and cultures. Moral norms are the results of personal beliefs and thoughts.

Conclusion
Human development crosses major periods of cognitive, psychosocial and moral development in correlation with the development of maturation of anatomical brain systems.