The Four Stages of Human Development

The growth and development of a human being is a continuous process from birth to death comprising of four key stages. These stages are namely adolescence and emerging adulthood, adulthood, late adulthood, and death and dying. The development of a human being through these four stages of growth is influenced by psychosocial, cognitive, and biosocial factors discussed below.

Adolescence and Emerging Adulthood

The adolescence to emerging adulthood growth and development stage occurs between the age of 15 years and 25 years. Individuals at this stage of growth and development experience biosocial changes as a result of a rapid increase of hormonal levels. Increasing hormonal levels contribute to physical changes such as the boys becoming more muscular and girls developing breasts. An adolescent boy’s shoulders grow wider as their voice deepens while a girl’s body becomes curvier as they gain weight around their hips accompanied by the significant growth of their breasts. Since adolescence to emerging adulthood is a transitional stage from childhood to adulthood, the individual experiences several cognitive changes. The individual develops advanced reasoning skills or problem-solving skills, think abstractly, and develop formal operational thinking. The individual develops the ability to investigate a full range of possibilities inherent to a context. Thinking critically enables the individual to imagine things that he or she has not yet experienced or seen. It is besides developing the capacity to think about one’s emotions and how to perceive them. The individual also experiences psychosocial development characterized by the establishment of an identity, autonomy, and future orientation. The individual strives to become economically and emotionally independent from parents. It is besides developing a sense of identity through a significant improvement in self-esteem and self-concept. The individual also develops realistic goals about their future career or vocations after developing a sense of identity and redefining their moral, sexual, and religious values. Understanding a person’s biosocial, psychosocial, and cognitive influences during the adolescence to emerging adulthood growth and development stage enable a person to under how their hormones influence a person’s identity development and self-concept.



The adulthood growth and development stage occur between the age of 25 years and 65 years, intermitted by two early and middle adulthood stages. The individual experiences changes at the molecular and cellular level. Biosocial influences at the molecular and cellular level lead to an increase in muscle strength, sensory abilities, reaction time, and cardiac functioning during early adulthood, between 25 years and 40 years. However, during middle adulthood, an individual experiences changes reminiscent of the body decline as the skin dries and wrinkles while the hair becomes thin and grey. It is also besides gaining weight on buttocks, upper arms, and other body parts. Meanwhile, cognitive influences at this stage lead to the development of relativistic thinking as the individual becomes aware of the complexities of life. Furthermore, crystallized intelligence grows steadily while fluid intelligence begins to decline. It is noteworthy that while physical abilities peak by mid-20s, a person’s cognitive abilities remain relatively consistent throughout early and middle adulthood. However, researchers encourage adults to engage in physical and mentally stimulating activities to postpone cognitive decline. Erik Erikson’s theory of psychosocial development suggests that throughout early adulthood, a person experiences psychosocial influences that lead to struggles between isolation and intimacy. The conflict centers on establishing intimate loving relationships with other people. Success leads to feelings of intimacy while failure is accompanied by feelings of isolation and loneliness. Understanding a person’s biosocial, psychosocial, and cognitive influences during adulthood enables a person to understand how their body changes at the molecular level affect their physical abilities to better deal with complexities of life such as employment and parenting.

Late Adulthood

The late adulthood stage of development occurs 60 years onwards when a person experiences the loss of skin elasticity and decline in reaction time as well as muscle strength and diminishing mobility. It is besides a decline in vision and hearing senses accompanied by weakness of the immune system. As the immune system becomes weak the individual becomes more susceptible to illnesses, diabetes, cancer, and other ailments. It is besides experiencing an increase in respiratory and cardiovascular problems. A person’s physical mobility is also affected due to a decline in balance, which results in falls and injuries. The individual also experiences cognitive developmental changes pertaining to a general decline in memory. It is a result of a steady decline in the speed of encoding, storing, and retrieving memory. This leads to problems with short term memory retention and a decline in a person’s capacity to learn new information. This explains why dementia and Alzheimer’s are particularly common during the late adulthood stage of development and growth Individual begins to experience frequent episodes of absent-mindedness as they grow older. Erikson’s theory of psychosocial development suggests that individuals undergoing late adulthood experience a struggle between integrity and despair. The individual wishes to retain their autonomy and independence despite declining physical and cognitive abilities. It is besides reflecting on the life lived reminiscing on the good times and regretting on opportunities missed. A person’s pride increases if they are comfortable with who they are while regret settles on if they missed or misused life’s opportunities. Understanding a person’s biosocial, psychosocial, and cognitive influences during late adulthood enables a person to prepare for life after retirement by reflecting on the life lived.

Death and Dying

The death and dying stage of a person is accompanied by physical and emotional changes. The body loses its physical abilities such as muscle strength and reaction time accompanied by a steady decline in mobility. The majority of the hair turns grey as the skin becomes dry and wrinkled in addition to losing vision and hearing senses. The individual also loses appetite as a result of a decline in taste senses. It is also a period when a person becomes less interested in the outside world and the specific details of daily life. The majority of the individuals at this stage become introverted by turning their interest inwards and becoming less socially involved with others. It is common for such individuals to only want to be in the company of a few people. It is a sign of introspection which signifies letting go and saying goodbye to everyone and everything they have known. In days before someone’s death, a person may enter a phase of unique conscious awareness and reflection that may be misinterpreted by caregivers and loved ones as illusions. The individual also develops an insatiable need to communicate with people whom they have wrong in preparation for the approaching death. It is also common for the individual to demonstrate distorted memory as recent events become intertwined with distant memories. Understanding a person’s biosocial, psychosocial, and cognitive influences on the stage of death and dying enables a person to prepare for their demise by resolving pending issues.