Human development is a continuous progress that is described in 8 different age periods from the prenatal period to late adulthood. The 8 stages of development are classified into 3 important domains such as physical development, cognitive development, and psychosocial development. (1) Erik Erikson who was a psychologist has created the most influential theory regarding the stage of psychosocial development. Erikson’s theory focused on the impact of social involvement and relationships on human through the 8 development stages. (2) On the other hand, traditional Chinese medicine (TCM) portrays a different perspective to the western model on human development. TCM believes that women are developed with a 7-year cycle whereas men developed with an 8-year cycle. Furthermore, the reason for deterioration is due to the weakening of Kidney-essence. (3) The infancy and toddlerhood, young adulthood, and middle adulthood are chosen 3 periods of human development and each period will be explained reflecting on 3 major domains including TCM aspect on these three periods.
Infancy and toddlerhood is the second stage of development and this stage refers to the period from birth to the age of 3. During this time, the sensorimotor and motor skills are developed thus they react very sensitively to the environmental changes. (1) At this stage, they discover the use of all their senses such as touch, taste, smell, hear and sight. (4) It is difficult to examine the cognitive development during infancy in comparison to physical growth but it is evident that they gradually develop in skills to learn and improve memory by the end of year 2, during toddlerhood. (5) Toddlers learn to use symbols, solve problems and show progress in language skills noticeably. (1) Erikson’s theory argues that during the infancy period, they learn to trust or mistrust others. (2) This is the period where attachment develops to parents or caretakers. (1) According to Erikson, the stage from birth to the first year is the most significant stage in life as it will affect the formation of personality in later stages of life. As they develop towards toddlerhood, children begin to have self-awareness or grow little independency which it gradually leads to establish autonomy. Toddlers who fail to attain success, they will experience shame and doubt. (2)
The young adulthood sits in the range of age from 20 to 40. During this period, physical condition is at climax and following that begins to decline. Belief and moral thoughts of young adults become more complicated as individual characteristics in terms of personality become relatively stable but can still be changed with very influential events. (1) They begin to expand personal relationships by contributing to society with education, occupation or marriage and become parents. This indicates the development of an intimate relationship. (6) According to Erikson, strong self-esteem is an important factor to establish an intimate relationship. He also suggests it is significant to develop a close and faithful relationship with people. For people who fail to establish a faithful relationship could fall into emotional isolation that results in loneliness, and depression. (2)
Middle adulthood ranges between ages 40 to 65. Individuals begin to slowly experience deterioration with their sensory abilities, stamina, health, energy levels and for women reach menopause tends to come about. At this stage, some people have a successful career, retired, or may seek a new job. People will have lost creativity but their mental ability is at the peak where they are proficient and have expertise in solving practical problems. (1) People at this stage encounter dilemma on generativity and stagnation. People move forward while focusing on career, and helping their children to grow as a trustworthy and mature adult. (6) Successful in giving birth to children, watch them grow, and harmonizing well with wife or husband are an very important accomplishment of this stage. People who are unsuccessful in this stage, they will feel stagnation and feel less involvement in society.(2)
According to TCM theory, Kidney plays an important role in birth, physical development, and deterioration process. Kidney-essence that is stored in the kidney is in control for growth, reproduction, development, sexual maturation, and aging. This indicates that Kidney-essence performs the role of hormone changes in western medicine which is involved in puberty, pregnancy, and menopause. (7)
This essence helps in physical development such as the growth of permanent teeth, hair, and height. After the birth of a human, the kidney-essence gradually increases and reaches at its peak during adolescence which triggers menstruation for female, and spermatorrhea for males. (8) By the age of 21 for female and 24 for male, the body development ends and this is when Kidney Qi level is at its maximum. From this period onwards, kidney-essence begins to decrease which emphasises deterioration. Women’s body begins to deteriorate from the age of 35 and starts to experience wrinkles or hair loss. By the age of 43, they experience skin sagging, begin to have white hair, and eventually reach menopause which they are usually no longer able to give birth. On the contrary, men experience deterioration from a later age than women, at 40 years. Male Yang-Qi reduces from the upper body which leads to having sagging skin and white hair from 48 years. The body weakens as the kidney-essence degenerates at 56 years and from 64 years they experience loss of hair and teeth. (3)
TCM believes that aging or deterioration is a result of a decrease in the essence whereas western medicine believes it is due to tissue damage, DNA modification, a decrease in the number of cells, depleted cellular function and unhealthy lifestyle. These are the common contributing factors of aging or deterioration described by western medicine. (9) Furthermore, people who have disorders in development, or mental and have soft and weak bones are the result of the imbalance of kidney-essence. (8)
The human lifespan has a standard 8 period that describes the common characteristics of human development from conception to death. However, each individual has a different physical appearance, lifestyle, energy level, and personality that are inherited from parents or formulated by the society they are associated with. This emphasises that the degree of development and aging are different to every individual within the same stage of development.