Introduction
The life-span perspective is the theory that human development occurs throughout a person’s life. As developed by Baltes, human development is multidimensional, encompassing physical, cognitive, and psychosocial growth (Baltes, 2019). Advanced research based on this theory posits that a human lifespan comprises eight stages. This includes prenatal development, infancy, early childhood, middle and late childhood, adolescence, early adulthood, middle adulthood, and late adulthood.
Each developmental stage is marked by milestones in the different facets of a human being’s life. However, healthy progress throughout the phases ensures that humans mature into independent and responsible adults. In light of this, this paper explores infancy, adolescence, and late adulthood to understand their holistic growth and development.
Infancy
Infancy is a critical development stage in human development that succeeds prenatal development. Biologically, infancy begins at birth and continues to 12 or 18 months (Baltes, 2019). Essentially, infancy ushers in the toddler phase and early childhood, where a child begins to experience psychosocial development.
One of the defining characteristics of infancy is that infants experience physical growth spurts, which are visible to their caregivers. At birth, a normal, healthy baby weighs 3.5 kilograms on average (Baltes, 2019). The weight of most babies at birth ranges between 3 kilograms and 4 kilograms.
During the first year, an infant gains 170g per week due to the development of their physical features (Baltes, 2019). Motor organs, such as the hands and legs, increase in size and muscle mass as overall body height increases. Due to rapid physical growth, infants sleep 16-18 hours a day to allow their bodies to rest and re-energize.
Physical development during infancy occurs in visual and auditory development. Immediately after birth, babies display involuntary reflexes such as kicks, blinking, and grasping. By the second month of development, reflexes increase in intensity as auditory-visual development progresses.
Snellen notation states that visual development progresses from 20/800 in the first two weeks to 20/70 by the fifth month and 20/20 at the twelfth (Orenstein & Lewis, 2022). The progress indicates that vision becomes clearer over the months leading up to 1 year, and infants begin to differentiate between dark tones (Orenstein & Lewis, 2022). Gradually, they can recognize human faces and their mothers. In terms of auditory development, an infant begins to hear tones that are repeated. For this reason, infants show responses to sounds and can play with their caregivers.
The development of auditory and visual senses during infancy sets the foundation for psychosocial development. Infants largely depend on their mothers and caregivers to feed them, put them to sleep, play with them, and support their overall development. Growing recognition of sights and sounds supports their psychosocial development through attachment to caregivers.
The initial emotions that reflect psychosocial development are distress and fear (Baltes, 2019). By crying, infants express emotions and can call for attention from their caregivers. The responses infants receive to their emotions shape their earliest attachment styles. It also informs their mental development in terms of dependency on other people for support. In addition, at 12 months, infants can imitate simple movements and reactions, which is the earliest sign of cognitive development.
Adolescence
Adolescence is inarguably the most critical developmental stage in a human being’s life span. This stage begins after childhood, from ages 13 to 19. It is an essential phase because of the holistic development it offers. Physical development during teenagehood manifests in masculine and feminine features in male and female teenagers, respectively (Orenstein & Lewis, 2022). Adolescents begin to experience hormonal changes that stimulate growth and weight gain. Additionally, hormonal changes influence the emotional tendencies exhibited by teenagers.
Psychosocial and cognitive development in adolescence occurs alongside physical development. In the general public, adolescence is called the identity state or the formative stage. This is because, at this point, teenagers begin to understand themselves, their interests, preferences, and personalities (Orenstein & Lewis, 2022). They also spend more time with their friends because they are more relatable and share similar interests.
The hallmark of these advancements is that the teenage brain undergoes a surge in neuronal growth. Unlike during childhood, puberty allows for the consumption and processing of information. Increased brain activity engenders keen observation, abstract thinking, creativity, and reasoning. This often predisposes teenagers to sensitivity in social interactions with their peers and parents.
Cognitive development in puberty emerges from the growth of the frontal cortex, a part of the brain. This part of the brain develops towards the end of adolescence, as one approaches 20 years, and may continue into the mid-twenties. The whole development and functioning of the frontal cortex enable teenagers to practice informed judgment (Lerner, 2021).
With proper judgment, teenagers can assess situations and make critical decisions. In reality, cognitive development from the frontal cortex is exhibited through planning, prioritizing, and self-expression. Engagement of cognitive abilities often causes conflict with other people who may want to control their social lives. Teenagers can develop theories, test them, and form their perspectives on issues that affect their well-being.
In line with cognitive development, teenagers reach major psychosocial milestones. One of these is that adolescents develop self-esteem and a sense of self-worth. Depending on their perceived self-identity, they associate with groups that align with their interests.
A distinguishing characteristic of adolescence is that it is the stage when a human being begins to experience sexuality (Lerner, 2021). Teenagers develop sexual interest in the opposite gender while also inclining to their own by seeking ways to enhance their outward appearances. Cognitive and psychosocial growth often leads teenagers to adopt more independent tendencies, indicating they are young adults.
Late Adulthood
Late adulthood is the last stage of a human being’s life span. Unlike the rest of the stages, this stage is complex and dynamic. How it occurs depends on many factors that affect an individual’s well-being at a vulnerable age. Generally, this is the phase that starts at age 65 and above. Health deterioration associated with old age tends to worsen. For example, vision loss and hearing loss worsen with age. Unfortunately, the percentage of the population that lives past 65 years is low due to declining life expectancy (Berk, 2022).
A typical feature of this phase is that human beings experience normal aging. This means an individual will experience decreased physical activity due to reduced body energy and strength (Berk, 2022). It also indicates health complications, including a predisposition to lifestyle diseases. Chances of being diagnosed with hypertension, diabetes, arthritis, and mental disorders skyrocket after one gets to 65 years (Berk, 2022). Seniors experience vision and hearing loss, while others experience dental problems. The body’s natural immunity weakens, predisposing it to health complications.
Late adulthood is characterized by deteriorating cognitive function, which can lead to a loss of independence. For example, most people in late adulthood experience Alzheimer’s and dementia. Both conditions indicate poor mental processes due to loss of brain elasticity. Loss of memory, poor judgment, and impaired reasoning become problems for older people who live alone (Spreng & Turner, 2019).
While there is no standard expectation, seniors experience old age differently. Research establishes that socio-economic well-being promotes healthy aging. Engaging in physical activity, maintaining a healthy diet, and exercising throughout one’s lifespan also increases the likelihood of healthy aging.
Key Learning from the Course
Learning about the lifespan perspective was interesting because it explores human existence as a linear process. I particularly liked that the course helped explain how change occurs in humans. In real life, people have ideals, perspectives, and values.
For example, adolescents are more cautious about how their peers perceive them. In middle and late adulthood, this changes as people become more carefree. Priorities change, and individuals in late adulthood delve into leaving a meaningful life (Berk, 2022).
The course helped explain the underlying developmental stages that ignite such changes. I was keener to understand the role of cognitive development in human behavior. This is the foundation of all human behavior, and the lifespan perspective examines it across every developmental phase.
I liked that the module provided a connection through the developmental stages. For example, physical development begins at birth, reaches its peak during middle adulthood, then plateaus and declines. Cognitive development, the deterministic function of all development, is more complex yet follows the same trajectory.
Psychosocial development, on the other hand, was more of a social construct and a result of one’s personality. Drawing these conclusions sets the basic foundation for understanding human development. At the same time, this allows for a connection of how the human body functions.
One of the key lessons that I learned is that human development is a continuous process. This simplistic principle means that development does not stop at any point in life. However, the lesson clarified that there are no clear-cut stages for development (Newman & Newman, 2022)—for example, cognitive processes in childhood build on those in adolescence and adulthood. The process is smooth and continuous, with one stage leading to another.
I also learned that human development begins with cognitive processes before physical growth and behavioral traits emerge. According to the theory, early developmental stages are crucial for the behavioral traits that form later in a person’s life (Newman & Newman, 2022). This sparked curiosity about what upbringing causes unconventional behaviors in adults.
Conclusion
The lifespan perspective provides an elaborate account of the trajectory of human life across developmental stages. This approach emphasizes continuous development with notable psychosocial, physical, and cognitive development. While these are plain and clear, research probes the impact of external factors on achieving optimum growth.
Even with the multidimensional blueprint, behavioral outcomes are affected by socio-economic factors (Newman & Newman, 2022). This cuts across family and community socialization, economic factors, and environmental exposure. All these factors work collaboratively to determine behavioral outcomes and overall quality of life. Understanding this engenders a deliberate effort to foster optimal human development at all stages.
References
Baltes, P. B. (2019). Life-span developmental psychology: Observations on history and theory revisited. In Developmental Psychology (79-112). Routledge.
Berk, L. E. (2022). Development through the lifespan. Sage Publications.
Lerner, R. M. (2021). Children and adolescents as producers of their own development. In Individuals as producers of their own development (pp. 75-102). Routledge.
Newman, B. M., & Newman, P. R. (2022). Theories of human development. Taylor & Francis.
Orenstein, G. A., & Lewis, L. (2022). Erikson’s stages of psychosocial development. StatPearls Publishing.
Spreng, R. N., & Turner, G. R. (2019). The shifting architecture of cognition and brain function in older adulthood. Perspectives on Psychological Science, 14(4), 523-542.