The aim of this paper is to describe the physical, cognitive and socio-emotional changes that occur throughout the lifespan, that is, from infancy to early, middle and late childhood and early, middle and late adulthood.
Infancy is a period during which infants make significant gains in weight and length. Their bones also harden due to the deposition of calcium and other minerals. Their muscles also increase in size and strength. The brain of infants also grows tremendously at a faster rate than the rest of the body. Infancy is also the period during which the infant achieves major milestones like crawling, walking, reaching and voluntary grasping (Sigelmann & Rider, 2009, p.163).
Infants at this stage generally gain knowledge through sensing and acting. They also achieve what Piaget termed as object permanence that is, the realization that objects continue to exist even when they are not seeing them. In addition, they start developing the ability to plan how they can achieve their goals and to do simple categorization. Their ability to store information also increases rapidly during this stage. They also start developing communication skills (Sigelmann & Rider, 2009, p.163).
On emotional development, the infant at birth is able to express distress and displeasure, by the time they are six months, they are able to exhibit anger, fear and distrust. By the time they are 8 to 10 months old, they can express anxiety, surprise, and frustration amongst other emotions. The social relations during the infancy stage are primarily with their parents and are based on attachment. Infants learn the basics of social interactions, environmental exploration and impulsivity at this stage. They also learn to differentiate themselves from others (Sigelmann & Rider, 2009, p.163).
Physical growth at this stage continues but at a much slower rate than that of infancy. Children at this stage therefore have a decreased appetite than those at the infancy phase. All primary teeth are developed by the end of the third year. Children at this stage also acquire more gross motor skills such as jumping and running skills and improve on eye-hand coordination. In addition, they start developing fine motor skills (Sigelmann & Rider, 2009, p.163).
Language development continues at this stage, basically children are able to form 3-4 word sentences; they are also able to do simple reading and writing. Other cognitive abilities that the child develops during this phase include the use of symbolic thought, understanding of entities and cause and effect, ability to classify objects and to understand numbers. Children at this stage are however unable to differentiate fantasy from reality, they also tend to have centration and transductive reasoning (Sigelmann & Rider, 2009, p.163).
At this stage, the child gains the following socioemotional skills, gender identification, ability to form peer relationships, and a sense of right and wrong. Of importance note however is the fact that children at this stage are self-centered in their interactions with others due to a lack of the ability to perceive the world from the perspective of others (Sigelmann & Rider, 2009, p.163).
Middle and late childhood
The child continues to grow increasing by about 1.5 to 3 kg in weight each year and 2.5 to 5 cm in height every year. Their bodies become more proportional due to the redistribution of fats and their bones continue to ossify. Other body systems continue to develop becoming more efficient. They also make significant improvements of their fine motor coordination skills as well as their muscular coordination (Sigelmann & Rider, 2009, pp.162-164).
Development of logical thinking is the main milestone achieved at this stage as far as cognitive development is concerned. This implies that children at this stage have the ability to plan ahead, to formulate alternate hypothesis, and to consider available evidence when reasoning. Language skills continue to develop and children at this stage are able to communicate clearly and persuasively (Sigelmann & Rider, 2009, p.163).
During this stage, children learn to take the perspective of others into consideration in their interactions with them. They also develop a broader peer context as well as enduring personal friendships. They also tend to spend a significant portion of their time with friends (Sigelmann & Rider, 2009, p.163).
An increase in the amounts of circulating growth hormone triggers a spurt of growth in adolescents. They increase both in height and weight although the distribution of the weight is different in the two sexes. Girls gain more fats especially in the breasts, hips and buttocks while boys make more gains in muscles. Adolescence is also the period during which secondary sexual characteristics appear such as menarche, growth of breasts in girls and increase in the size of scrotum, testis and penis, growth of pubic and facial hairs in boys amongst others. These changes are triggered by an increase in the amount of gonadal hormones in both sexes (Sigelmann & Rider, 2009, p.166).
During this period of growth, children develop the ability to think abstractly. Their ability to apply the principles of logical reasoning also develops fully at this stage (Sigelmann & Rider, 2009, p.166).
Adolescents exhibit egocentrism in their relations with others hence they tend to be rebellious, critical of people in authority and to be quick in finding faults in others. They also experience a wide range of emotions and variations in their level of self esteem. Whilst the self esteem of boys increases during this period, that of girls tends to decrease. Adolescents also develop more intimate relationships with others. They are also more easily influenced by peer groups during this stage (Sigelmann & Rider, 2009, p.166). Of most importance however is the fact that this is the period during which people seek their own identity.
This period is marked by very minor physical changes. It is the stage during which nearly all the organ systems reach their peak functioning capability. The body at this stage has started aging although the effects are not visible (Sigelmann & Rider, 2009, p.168).
Cognitive performance across different tasks increases. For instance, performance in terms of perceptual speed and numerical abilities peaks during this stage (Martin & Zimprich, 2005).
Basically, young adults are more committed in their relationships with others and they tend to seek more intimacy and stability in their relationships. It is also during this period that they first experience parenthood (Whitbourne & Sliwinski, 2011, pp.236-239).
Adults at this stage experience a number of age-related changes for instance their skin becomes loose, wrinkled and dry, their hair becomes thinner and turns grey, they gain weight amongst other changes. The efficiency of majority of the body systems such as the lungs and the heart also declines. Women experience menopause during this period when they are 45 to 54 years old while men experience andropause (Sigelmann & Rider, 2009, p.168).
Cognitive development during period is influenced by a number of factors such as job and family related demands and hormonal changes. Typically, cognitive functioning peaks during middle age especially inductive reasoning, spatial memory, vocabulary and verbal memory. It is also the age during which fluid and crystallized intelligence abilities start to decline (Martin & Zimprich, 2005).
It is during this period that people undergo a mid-life transition whereby they reevaluate and modify their lives and relationships. Women at this stage experience a range menopause related emotional changes such as irritability. The emotional experiences during this period are also influenced by factors like one’s job, children, finances and sex life (Whitbourne & Sliwinski, 2011, pp.236-240).
Adults at this stage experience many physical changes like decrease in bone and muscle mass and marked declines in the efficiency of nearly all the organ systems (Sigelmann & Rider, 2009, p.168).
Cognitive performance undergoes a steady decline during this period to an extent that it ends up affecting an individual’s level of independence in carrying out day to day activities. Fluid and crystallized intelligence continue to decline (Martin & Zimprich, 2005).
Adults at the early phase of this stage are quite active and influential socially and politically. Their interactions with others though less frequent are more satisfying and supportive. No significant changes in their levels of self-esteem or satisfaction with life occur (Whitbourne & Sliwinski, 2011, pp.236-240).
In conclusion therefore, humans go through numerous physical, cognitive and socio-emotional changes across their life span. Majority of these changes do not occur as distinct entities in the each and every stage but as a continuum experienced across the various stages.
Martin, M., & Zimprich, D. (2005). Cognitive development in midlife. Retrieved from
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Whitbourne,S.K., & Sliwinski, M. (2011). The Wiley Blackwell handbook of adulthood and
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