The human brain is clearly the most marvelous of all of Nature's creations. This sample science research paper discusses the development of the brain over the course of the human life cycle.

The brain's development from infancy to adulthood

Relative to many other animals, the human being is a creature who is born in an extremely vulnerable state; the newborn infant needs nurturing caregivers for an exceptionally long time before they are able to take care of themselves. This is at least partly related to the fact that the infant's brain is not yet fully formed. As the organization Zero to Three has put it:

"The first three years of life are a period of incredible growth in all areas of a baby's development. A newborn's brain is about 25 percent of its approximate adult weight. But by age 3, it has grown dramatically by producing billions of cells and hundreds of trillions of connections, or synapses, between these cells" (paragraph 1).

The development of the human brain over the first couple years can thus only be described as tremendous: the infant is not born with a fully development brain, but he clearly develops one soon enough.

Infant brain development

At the level of mind, one of the main correlates of this development in the brain is clearly the infant's acquisition of language. Language is one of the human species' unique evolutionary advantages over all other known species in the world. Kopko has suggested:

"infants learn language according to a highly organized set of rules containing five systems: phonology, morphology, syntax, semantics, and pragmatics," and that "despite the number of different languages in the world, infants learn a language in a universal, relatively predictable pattern" (2-3).

This implies that the basic language acquisition process can likely be linked to the development of the basic structures of the brain itself. It is well-known that the vast majority of children are capable of using language in a coherent (if rudimentary) way by the age of 2 of 3 years. That is, the language acquisition process substantially overlaps with the initial developmental explosion that takes place within the brain of the infant.

Childhood and adolescent brains

The brain of the child continues to develop in highly significant ways. The Center on the Developing Child has described this growth in terms of the key concept of brain architecture:

"Cognitive, emotional, and social capacities are inextricably intertwined throughout the life course...Emotional well-being and social competence provide a strong foundation for emerging cognitive abilities, and together they are bricks and mortar of brain architecture" (paragraph 5).

The development of brain architecture is one of the fundamental processes that occurs over the course of childhood. In principle, this process continues over the entire course of the human lifecycle; however, imprints that are made during childhood not only tend to be more powerful than subsequent imprints, they are also made much more easily and readily they are later on in life.

Such early imprints could perhaps be overcome later on in life, but it would take considerably more effort and work, relatively speaking, to make this happen. This is part of why it is so important for the child to be given a nurturing environment, and why childhood trauma can often prove so difficult to overcome.

Understanding childhood personality and "mimicking" behaviors

The development of the child's brain can also be conceptualized in terms of a progress through multiple circuitries that structurally mimic the development of the human species as a whole. This is the kind of model, for example, that has been developed by Wilson. First, the child learns how to respond to the world simply on the basis of primitive survival impulses; then, he learns to engage with other members of his species on an emotional-territorial level; then the child learns how to utilize and master the language.

These behavioral developments can be understood as correlates of the initial infant development of the brain, followed by the solidification of brain architecture as the child's emerging experiences interact with his neurological hardware in a dialectical way. On the one hand, the brain's architecture itself plays a determining role with regard to what experiences the child will have; but on the other, it is also the case that new experiences, and especially during childhood, can exert a significant influence with regard to actually altering the structures of the brain's architecture itself.

Adolescence and hormonal influences of the brain

As the organization Act for Youth has somewhat humorously written:

"Research now supports what parents have long suspected—that the teenager's brain is different than the adult brain. Recent research by scientists at the National Institute of Mental Health (NIMH) using magnetic resonance imaging (MRI) has found that the teen brain is not a finished product, but is a work in progress" (1).

In principle, of course, the same thing could be said about any given human brain, as long as the owner of that brain is still alive. In the adolescent in particular, though, a whole new stratum of the brain is in the process of being formulated. Neurologically, this is reflected in the massive production of gray matter: the only other time in the human lifecycle where such a thing happens is infancy.

This production is then followed by a process of what is called pruning, whereby the brain strengthens the neural connections that are most often used while allowing the ones that are not used to fade away. This solidifies the architecture of the brain and generally improves the efficiency and effectiveness of cognitive functioning.

Developing a deeper meaning of life during the teenage years

At the level of mind, these neurological developments have one fundamentally important correlate: that is the emergence of the capacity for abstract thought (Piaget). Throughout childhood, the person is essentially determined by his environment and surroundings; he does not really have the cognitive capacity to imagine new possibilities, and then work toward bringing those possibilities into being. The adolescent, however, is able to access the power of abstraction, and thereby conceive of himself as a self who is in some meaningful sense independent from his immediate surroundings.

This is the basic cognitive cause of the common perception that adolescents tend to become introverted, or aloof, or rebellious: these behaviors are the result of the emerging sense of self, which in turn is the result of the onset of the capacity for abstract thinking. Moreover, these dynamics are clearly also compounded by the emerging awareness of sexuality and social morality, which can in its own way be understood as being as fundamental a development shift as previous concerns with survival, territoriality, and semantics (Wilson).

A working understanding of the development of the adolescent brain can clearly have important implications for the practice of parenting. In particular, the neurological evidence strongly suggests that the adolescence is in fact going through a process a serious cognitive development, and that this process has a neurological as opposed to merely sociological or cultural basis. Ideally, the adolescent would be provided with a nurturing environment within which he can pursue this phase of his development that achieves a balance between his competing demands for structure and freedom.

Continuing brain development through adulthood

Throughout adulthood (the beginning of which, for present purposes, can be defined as beginning in about the mid-20s), a given person's cognitive and neurological development tends to stabilize, and he primarily engages with the physical and social world on the basis of the brain architecture that he has developed over the course of his infancy, childhood, and adolescence.

Significant changes could still theoretically happen, especially if a given person has powerful experiences that cannot be accounted for by his existing brain architecture; but it would seem that this does not happen very often; it would be fair to call such development more of an exception than the norm. Neurologically speaking, to have become an adult almost by definition means that one's brain architecture has become stable, to the point that subsequent experiences will be assimilated into the existing architecture as opposed to exerting a serious influence of change over that architecture.

At the cognitive level, middle age is characterized by both decreases in function in some areas and increases in function in other areas. As Phillips has written:

"While memorization skills and perceptual speed both start to decline in young adulthood, verbal abilities, spatial reasoning, simple math abilities and abstract reasoning skills all improve in middle age" (paragraph 6).

This would seem to parallel the broader point that while the adult brain stops developing in as qualitatively an extreme way as it did in previous phases of the human life cycle, it nevertheless continues to assimilate new experiences into its existing architecture and grow in a quantitative, accumulative way. Moreover, it is possible that many adults may simply underestimate their own cognitive abilities, due to both cultural and personal perceptions regarding the effects of aging on those abilities. It is also the case, of course, that people have a natural tendency to take gains of any kind somewhat for granted, while dedicating conscious attention to losses in a disproportional way.

Works Cited

Act for Youth. "Adolescent Brain Development." May 2002. Web. 13 Aug. 2015. http://www.actforyouth.net/resources/rf/rf_brain_0502.pdf.

Center on the Developing Child. "Key Concepts: Brain Architecture." Harvard University, 2015. Web. 13 Aug. 2015. http://developingchild.harvard.edu/key_concepts/brain_architecture/.

Kopko, Kimberly. "Research Sheds Light on How Babies Learn and Develop Language." Cornell University Department of Human Development, n.d. Web. 13 Aug. 2015. http://www.human.cornell.edu/hd/outreach-extension/upload/casasola.pdf.

Phillips, Melissa Lee. "The Mind at Midlife." Monitor on Psychology 42.4 (2011): 38. Web. 13 Aug. 2015. ;http://www.apa.org/monitor/2011/04/mind-midlife.aspx.

Piaget, Jean. Possibility and Necessity. East Sussex: Psychology Press, 1987. Print.

Wilson, Robert Anton. Prometheus Rising. New York: New Falcon Publications, 2009. Print.

Zero to Thee. "Brain Development." 2014. Web. 13 Aug. 2015. http://www.zerotothree.org/child-development/brain-development/.