There are many beginnings to the study of human development. The study of human developments is a science that strives to discern how people change over time (Berger, 2011). To do this, developmentalists study all types of people from different age groups, ethnicity, culture, background, nationality, income, and sexual orientation, among many other factors. To begin to understand this science, one must start by looking at what is being studied, some of the major theories that shape and guide these studies, and the interaction of heredity and the environment on human development (Berger, 2011).
Developmentalists seek to tackle the challenge of defining humans in a way that simultaneously describes the universalities of humans as well as their differences. Because development is not limited, the person is the result of interactions among all the systems known as microsystems, macrosystems, and exosystems (Berger, 2011). Another aspect of development is that it encompasses the changes and uniformities of people. A visionary in the study of development was Urie Bronfenbrenner, who introduced an ecological-systems approach to the study of development (Berger, 2011).
The ecological-systems approach recommends that human development should be studied by looking at the interactions and contexts that make up a person’s life. There are three levels that Bronfenbrenner proposes each person is affected by: microsystems, exosystems, and macrosystems (Berger, 2011). Microsystems are described as foundations of the person’s nearby surroundings, while an exosystem is described as the person’s local institutions. For example, a person’s family would constitute a person’s microsystem and their place of work would be their exosystem. A person’s macrosystem is their greater social settings, such as their cultural values and economy (Berger, 2011).
Bronfenbrenner understood that development changes over time and, therefore, included two other systems that interact with the original three; the chronosystem and the mesosystem. The chronosystem encompasses the historical conditions that affect the other systems and the mesosystem consists of the correlations between the three systems or parts of an individual system. In other words, the mesosystem refers to the connections between home and school, communication processes, and macrosystem factors that affect the microsystem (Berger, 2011).
Understanding the shared connections between one area of life to another led developmentalists to form five standards that are beneficial for understanding human life at any age. These five characteristics are multidirectional, multicontextual, multicultural, multidisciplinary, and plasticity (Berger, 2011). Development is multidirectional, meaning that change occurs in every direction, with gains and losses, predictable growth, and unexpected transformations being apparent. Every aspect of life, including, intellectual growth, social interactions, and physical health are multidirectional (up, down, constant, or irregular). Additionally, in late adulthood, during old age, people tend to center on the declines rather than the gains, placing a particularly important emphasis on multidirectional change (Berger, 2011).
Human lives are multicontextual, meaning life is made up of many situations, including past circumstances, economical limitations, family patterns, and physical surroundings (Berger, 2011). To put it another way, every context has an impact on the person. For example, the paths available to the individual are dependent on the historical and socioeconomic conditions. Developmentalists note that the socioeconomic status of a person greatly affects their opportunities and limitations, advantages and disadvantages, and past history and future prospects, which affect the person’s habits, knowledge, housing, and nutrition (Berger, 2011).
The development of humans is influenced by many cultures. The multicultural principle understand that cognition and behavior are affected by the cultural environment, which includes the person’s social group, ethnicity, race, heritage, and even income (Berger, 2011). It is important to note that culture is dynamic, and people are capable of accepting or rejecting culture values. The study of life span and human development is multidisciplinary; it is interrelated with various fields of academia. While psychology, biology, sociology, and education are major players, other fields such as neuroscience, anthropology, history, and economics play a role as well. (Berger, 2011) Multidisciplinary is important to the study of development because people grow in mind, body, and spirit simultaneously.
The final characteristic is plasticity. Plasticity plays a role in the other four characteristics of development. It is an important characteristic because it represents two corresponding aspects of development (Berger, 2011). Plasticity understands that humans are capable of being molded, like plastic, while still maintaining a sturdy identity. Plasticity is affected by both culture and upbringing, as well as genes and other biological influences. The five characteristics led developmentalists to one conclusion: humans are individuals, whether or not they come from the same cohort, culture, or economy (Berger, 2011). Even though scientists have concluded that every person is an individual, there are still many questions about human development left to answer, which led to five major theories of development.
Developmental theories offer structure for clarifying the patterns and problems of development. There are several theories of life span development such as the three grand theories: psychoanalytic, behaviorist, and cognitive (Berger, 2011). The grand theories of human development, which explain the collective development and processes throughout the entire life span, began in the field of psychology; observations and clarifications deriving in history, biology, sociology, and anthropology led to the emergent theories. The two emergent theories are not yet as coherent as the grand theories, but they draw on more academic disciplines providing a broader framework than the customary grand theories that rely only on psychology (Berger, 2011). Discussed here are the two emergent theories: sociocultural and epigenetic.
The main concept of sociocultural theory is that human development is the result of a dynamic interaction between a person and their society. This concept is based on the idea that the tools and principles for development are provided by not only customs, but society as a whole (Berger, 2011). The pioneer of the sociocultural perspective was a man named Lev Vygotsky. By studying the cognitive competency of his diverse society, he developed a theory of guided participation. Guided participation is a technique in which novices learn through shared involvement of an activity with instruction and the participation of a skilled mentor (Berger, 2011). Sociocultural theory places an emphasis on social interaction in learning. Gauvain (1998) stated, “cognitive development occurs in, and emerges from, social situations” (p.191).
Another concept of learning in sociocultural theory is the zone of proximal development (Berger, 2011). The zone of proximal development is the metaphorical zone encompassing a learner that contains all the concepts, skills, and knowledge that the individual is proximal to attaining but cannot yet master without assistance (Berger, 2011). By extension, whether a person is learning a language, social custom, or manual skill, people always learn in the same way, according to sociocultural theory. Although it is true that people do learn in social settings, sociocultural theorists have been criticized for neglecting developmental processes that are not predominantly social (Berger, 2011).
Epigenetic theory is centered on the notion that development is influenced by the interaction between genes and the environment. To develop this theory, researchers incorporated many disciplines including biology, chemistry, and genetics (Berger, 2011). Half of epigenetic theory looks at the genetics, referring to the entire genome, and looks at the specific genes that make each person unique and the genes that distinguish humans from other species as well as the genes that all species share. Genes influence all psychological traits as well as mood, metabolism, voice tone, blood type, and much more (Berger, 2011).
The other half of epigenetic theory looks at the influence of surrounding factors on genetic expression. These factors are what gives some genes extensive influence while others have no effect (Berger, 2011). As development continues, each person continues along the path established by earlier genetic-environmental interactions, which influences outcomes. According to epigenetic theorists, genes never function alone, their latent is not realized unless certain epi-factors transpire (Berger, 2011).
Furthermore, epigenetic factors also influence groups of people and entire species. One way this happens is through selective adaptation, which is the progression by which humans and other organisms slowly adjust to their environment (Berger, 2011). In other words, over generations, a certain genetic trait in a population will increase or decrease. This depends on whether or not the trait promotes the survival and reproductive capability of that population. The particular environment is what determines which genes are harmful, neutral, or beneficial. According to epigenetic theory, adaptation occurs for all living organisms, regardless of the environment. Unlike sociocultural theory, many facets of epigenetic theory are generally accepted (Berger, 2011).
To further explain the interaction of heredity and the environment on human development, one must look further at the role genes play in the development of a person. There are two major contributors to development: the genotype and the phenotype. The genotype is comprised of all the genes of a developing person. The genotype is responsible for the formation of the body and the brain (Berger, 2011). The phenotype is the appearance and behavior manifested in a person. The phenotype is dependent on many genes and the environment, with most traits being polygenic (affected by many genes) and multifactorial (influenced by many factors).
Other contributors that influence the phenotype are additive alleles, which can affect height and skin color. Other additive alleles, called epistasis, produce traits that were not previously found in their ancestors (Berger, 2011). Every aspect of human behavior is affected by genes, this includes cognitive and social behavior. Personality and cognitive abilities are affected by many genetic combinations, with the genes relying on the environment for expression. No behavior could exist without genes and without the environment, no gene could be expressed (Berger, 2011).
In conclusion, the study of human developments is a science that attempts to understand how people change over time. Developmentalists formed five characteristics that are beneficial for understanding human life at any age: multidirectional, multicontextual, multicultural, multidisciplinary, and plasticity (Berger, 2011). Additionally, theories of development present introduce organization for understanding the patterns and problems of development. Sociocultural theory suggests that human development is the result of a dynamic interaction between a person and their society, while epigenetic theory is centered on the idea that development is shaped by the interaction between genes and the environment. Every aspect of human behavior is affected by genes and without the environment, no gene could be expressed (Berger, 2011).
Berger, K. S. (2011). The developing person through the life span (8th ed.). New York: Worth Publishers. Gauvain, Mary. (1998). Cognitive development in social and cultural context. Current Directions in Psychological Science, 7, 188-192.