Factors and Theories of Ageing

Zartasha Ahmed [due 15/03/15]


There are many theories attempting to explain the inevitable biological process of ageing, and there is a lot of evidence to support each one. However none of these theories are definitive, they only explain a certain chance or probability of a cause of ageing. Therefore these theories are linked, for example the wear and tear theory contains parts of the free radical theory. This means all biological theories could play a part in the process of ageing, there is no singular explanation to determine life span or rate of ageing. Similarly the psychological theories cannot be proven and they are just speculation, however they provide an interesting non-biological side to ageing.

Theories of Ageing


Genetic pre-programming theory

The genetic theory of ageing believes our lifespans are largely determined by our inherited genes. This theory believes our lifespan is predetermined from conception.

The theory uses parents who live long and have children who live equally as long as evidence, it is usually the mother who determines lifespan as mitochondrial DNA is maternally inherited. However this evidence could be disproved as lifestyle and learned behaviour, such as eating habits.

Certain genes that impact a person's internal functions can increase lifespan. For example, a gene that helps metabolize cholesterol will reduce the risk of heart disease. However some genes are harmful, such as those which increase the risk of cancer. These genes are usually inherited however some may mutate after birth.

Genes are believed to be have 35% influence on a person's lifespan. The remaining 65% is due to behaviours, lifestyle, routines, and exposure.

Free Radical Theory

The free radical theory believes ageing is caused by oxidation of cells from free radicals. Free radicals are atoms that have been made with one less electron in it's outer shell, making it highly reactive. For example during aerobic respiration, free radical oxygen can be produced which will rip an electron out of another atom. This sets off a radical chain reaction, as there will always be an atom which needs an electron to become stable. Free radicals are more likely to be produced in a person who smokes, is exposed to a lot of radiation (uv, xray, gamma) or pollution, is under stress, or consumes certain medication or food additives.

This affects ageing because free radicals cause damage to mitochondrial DNA, the rate at which this happens determines a person's lifespan. The free radical oxygen steals electrons from atoms in cells, therefore making the cells malfunction. In some cases, this can cause cancer cells to develop.

This process can be slowed by antioxidants, which stabilize the harmful free radicals. These can be found in colourful fruit and vegetables, such as sweet peppers and pomegranates. If the free radicals are stabilized, they cannot cause damage to the mitochondrial DNA which slows a person's predicted rate of chemical ageing.

Wear and Tear Theory

The wear and tear theory believes ageing is due to the damage of cells over time, as cells are regularly replaced in the human body.

When it is time, a cell makes a copy of itself and replaces the old cell. Cells that are replaced will be new, however the copy will not function as effectively as the original. Over time these cells degenerate and some may even be copied with a defect or mutation that changes how the cells functions.

This contributes to ageing because less efficient cells degenerate the body. New liver cells slowly lose their efficiency to process toxins, therefore the harmful toxins cause additional damage to the body. Over time new skin cells deteriorate, and there is less collagen in the skin. Collagen keeps skin plump and healthy, which explains why older people develop wrinkles and drooped skin.
The done can be slowed by making lifestyle changes that take care of cells and body systems. For example, a healthy diet will give the body nutrients to function optimally. Also, not coming into contact with anything harmful such as radiation or artificial food additives will reduce cell mutations.

This theory can explain most illnesses, for example cancer. Certain carcinogens such as radiation exposure can cause a healthy cell to become defective when it replicates itself. Thankfully the body has a mechanism called apoptosis which seeks unhealthy cells and destroys them before they can replicate themselves. However in some cases a defective cell will replicate itself before it is destroyed, therefore becoming a permanent mutation. These mutations accumulate and most are harmless, however the more mutations a person has; the higher their risk of cancer.


Erikson's Life Stage Theory

Erikson's life stage theory was greatly influenced by Freudian theories, however Freud studied the id whereas Erikson studied the ego. He believed the impact of culture, society, and environment outweighed the impact of the id/super ego conflict. He believed ageing was related to a person's own identity and overcoming internal crisis'. He identified 8 life stages that a person goes through, focusing most on infancy to adolescence as this is where most identity development occurs. He pairs each life stage to a psychosocial crisis to overcome and a basic virtue to follow.

The first stage happens at infancy, 0-1.5 years. A person follows hope at this stage, battling trust and mistrust. An infant is incredibly uncertain and insecure about the world their environment, therefore looking to their primary caregiver for support and stability. If they receive consistent and reliable care, they will develop trust which will prepare them for future relationships. Success in this stage will lead to hope, hope that they will be able to trust someone in times of crisis. Failing to develop trust at this stage will lead to the development of fear and no hope of support.

During early childhood, the second internal crisis occurs; autonomy vs. shame. This happens at 1.5-3 years and the basic virtue at this stage is will. At this stage, a baby gains independence from it's mother and starts making choices. Erikson believes it is very important to allow babies to explore their freedom and limits at this stage, with parental encouragement and patience. The goal at this stage is to support and encourage a baby's success while still protecting the child from scorn and constant failure. If successful, they will develop a sense of will and feel confident. If unsuccessful they may become very dependent on others and experience low self esteem and shame.

The third stage is initiative vs. guilt, this happens at age 3-5; known as the play age. The goal at this stage is to develop purpose. At this stage children begin to assert themselves more, which parents may see as aggressive behavior. They key aspect of this stage is play and interacting with other children to explore their interpersonal skills. This gives children the opportunity to create games, plan activities and assert themselves in groups; which develops a sense of initiative. If this is interrupted by criticism or control, children will feel insecure in groups and choose to play along or become followers who lack self initiative. Children begin to assert themselves and parents will usually respond by restricting the child for their own protection. The child will usually try to overrule their parent's judgment which can lead to them punishing the child; which restricts their initiative too much. Furthemore this is the stage in a child's life where they ask their parents many questions, If the parents treat these questions as trivial or annoying, they will grow up feeling they are a nuisance and develop a sense of guilt. This will slow the child's interaction with others and stunt their creativity. However some guilt is needed to teach the child self control and develop their conscience.

At school age, ages 5-12, a child's basic virtue is competency. This is reached by resolving the conflict between industry vs. inferiority. At this stage, parents step back and allow teachers to give their child support and skills. They learn to read, write, do sums, and do artistic projects. This stage is where children desire praise and acceptance by their peers and teachers; by demonstrating competencies valued by society. If children are encouraged and reinforced they will feel industrious and confident in their ability to reach goals. If the child is restricted by parents or teachers, they will start to doubt their abilities and feel inferior. If a child feels they cannot develop a specific skill they may feel inferior. Although some failure is needed to teach the child modesty, developing a sense of competence.

At adolescence, age 12 to 18, the basic virtue is fidelity. Ego identity battles role confusion. This stage is very important as children begin to look at their role in society and reexamine their identity. Erikson believes there are two identities; sexual and occupational. At the end of this stage, a person should have a sense of what they want to be/do and what sexual roles they identify with. At this stage it is expected that adolescents have issues with their appearance and body image, overcoming this and accepting themselves will lead to the virtue of fidelity. This means they will be able to commit themselves to a their own identity and accept other people's identities; although they may have different ideologies. During this stage a person's environment and experiences form their personal identity and place in society. Role confusion happens if a child does not explore their environment, thus making them unsure of what they want to be in life. As a result of this, they will experiment with different work, social, political lifestyles. Also, pressuring a person to take on a certain identity will result in rebellion, a negative identity, and feelings of sadness.

At young adulthood, a person battles intimacy vs. isolation. This happens 18-40 years old and the basic virtue is love. This stage is the first time people develop intimate relationships and commitments with a person who isn't a family member. Sexual interests grow and a person feels inclined to find a partner as they crave intimacy. Success at this stage will lead to a person feeling a sense of commitment, safety, and care within a relationship. Avoiding intimacy and failing to develop long term relationships will lead to isolation, loneliness, and even depression. Success at this stage will lead to love.

Age 40-65 is defined as adulthood and is where a person's basic virtue is care, resolved by the battle between generativity vs. stagnation. At this stage people are settled into stable careers and adapted to family life. This evokes a feeling of being part of a bigger picture; by raising children to be positive parts of society, being productive at work, and taking part in activities that can have a positive influence on the community. Success at this stage leads to the virtue of care. Failure at this stage will make a person become stagnant and unproductive.

Maturity occurs at 65+ and the basic virtue is wisdom; which is resolved through ego integrity vs. despair. At this stage, productivity slows and people start to explore retirement. They look through their lives and evaluate their choices and experiences, developing integrity if they see themselves as leading a successful life. If people see their lives as unsuccessful or unproductive, they feel guilt and that they did not achieve enough of their life goals. This creates feelings of despair, dissatisfaction, depression, and hopelessness. Success in this stage leads to wisdom, as they can look back on life with closure and acceptance.

Activity Theory

The activity theory defines ageing as a person staying mentally and physically active so they maintain a level of productivity to age successfully. The basis of the theory is; the more productive you are, the better you will age. Biologically it implies daily activity keeps the heart healthy and stops a lazy lifestyle. The feeling of productivity released hormones in the brain that make a person feel good, making them more motivated, energetic, and in touch with their environment. This applies to a person of any age, whether they are a small child or older adult.

However this theory has been dismissed as it is not enough to say a busy lifestyle leads to better ageing. This theory was designed for older adults who needed more activity in their lives to reduce the risk of them becoming withdrawn and out of touch with their surroundings. It has been decided that a heightened level of activity is important, however it cannot simply be hard, labouring work. It must be engaging and fulfilling to ensure the person does not exert themselves and they are mentally stimulated.

This theory stresses the balance between productivity and satisfaction. One must be physically active enough to stay fit, yet relax enough to not exert themselves. They must be mentally active enough to stay in touch with their surroundings, but relax enough to not feel over stimulated.

Disengagement Theory

The disengagement theory believes as people get older, they withdraw themselves from society and society in turn pushes them away. Older people have had their limitations defined and workplaces now prefer to replace older adults with younger people. This may be because of cheaper wages, more efficient labour, or a discriminatory view of the elderly. This causes an older person to feel inadequate and unneeded, thus making them step back and stop engaging in their daily life. In older adulthood, a person's work and social circles become smaller and they interact with far less people, which means their social needs may become unfulfilled; leading to sadness.

Supporters of this theory believe it's main basis is to prepare older adults for death, by slowly letting go of society and their environment and withdrawing themselves to live a quiet, peaceful life. Sociological views of this theory say it is beneficial to society, as older people are required to step aside so younger people can replace them and society can grow and develop with each generation.

However many believe this theory is society's excuse for excluding the elderly, as many current beliefs say that the elderly can still live a happy and healthy life as an active part of society. For example, older adults with health conditions that employers have to accommodate may be turned down on the basis that they are 'not what they are looking for.