HDFS 005          Human Development             The Main Points

[Updated 20 September 2006]

Introduction


We will take a multi-disciplinary look at normal individual human development.
We will try to understand the processes and principles of development.
Important perspectives are:  Developmental, Constructive, Transactional, Contextual.
Each of the human sciences has a slightly different perspective on development.
Development can be differentiated into several domains for conceptual purposes.
Development includes transitions, events, stages, plateaus.
Domains, stages, and transitions can be organized into a life-span matrix.
Some transitions are universal; others are individual.
Change or experience in any domain may affect each of the others.
Change or experience at any point in development may be related to change or experience at other times.
My perspectives:  These perspectives are not mutually exclusive.
     Developmental:   A person is always changing, coping, adapting, and learning.  It is useful to ask what is the person trying to learn or develop, rather than asking what is wrong with the person.
     Constructive:  A person is actively trying to make meaning of experience.  A person is applying understanding and skills to new experiences, and through practice and extension, is integrating the meaning made from new experiences into ever larger, more complex skills and understanding.  People understand what they themselves construct from their experience, not necessarily what another person wants them to understand.  People understand by interpreting the new experience in terms of what they already understand.
     Contextual:  The person is always in a physical, intellectual, and social context with specific opportunities, expectations, and risks.  The context helps shape what the person can do and learn, and thus how the person will develop.  Development cannot be understood without understanding the context in which it happens.
     Transactional:  Most important relationships involve mutual influence and are dynamic systems.  In relationships, each person contributes his or her actions, to which the other responds.  The resulting transactions constitute a significant element of each person's development.  The developmental perspective applies simultaneously to each person in the relationship.  The notion of transaction also applies to the relationship between a person and the environment.



Biological Development


The individual life span begins with conception, the union of ovum and sperm.
The resulting single cell, the zygote, carries the full complement of genes organized into 46 [23 pairs] chromosomes.
Genes direct the physiological functions of the cell.
The zygote, including the nucleus and its DNA, divides, making two identical cells, each with the same DNA/genes.  The resulting cells continue to divide, until there are the trillions of cells that make up the complete human being.
As the person develops, the dividing cells differentiate into different types of cells, eventually hundreds of different types in each human.
Cells exist in an environment, and the actions of genes depend in part of the specific conditions of the environment surrounding the cell.
Any characteristic that is genetic has to be manifested at the cellular level.
Genetic potentials are expressed within a range of possibilities that is determined in part by environmental conditions and the resulting experience of the organism.
Individual development is directed or shaped by heredity and by experience, inseparably.  The interesting questions are how much is each involved and how do they interact.  The “controversy” or "question" about “nature or nurture” is the result of invalid concepts of how genes work and how development occurs.

Prenatal development is progressive and systematic, and very complex.
Development involves progress from an undifferentiated or global state, to differentiated, and then to integration of differentiated components into complex systems.
The sequence, undifferentiated to differentiated to integrated, occurs both in structure and in function, and in many aspects of development, including cognitive and psychosocial.
Developing systems are most vulnerable to influence when they are changing.
The fetus and the mother engage in a variety of biological transactions over the course of gestation.
Birth instigates several necessary adaptations for the newborn.
Newborns arrive prepared or "tuned" to engage in social interactions.
Newborns exhibit differences in neurological function and style of transaction with the environment.  We call these differences "temperament."
The brain develops in several different ways, including:  proliferation of neurons, migration of neurons to appropriate locations in the brain, generation of synapses, increases in cell size, cell pruning, synaptic pruning, consolidation of cell assemblies or pathways, and myelination.
Motor development begins with reflexes, which are exercised, gradually coordinated and extended, and made into voluntary actions.
Actions are refined and integrated into more complex, coordinated actions.
The sequence and progress of motor skills are determined by the structure of the body, the features of the physical environment that can be explored, and the motivation provided by the infant and by her interactions with her caregivers.
Enriched opportunities for, and encouragement of, experience lead to more complex skills and more complex skills lead to more opportunities.
Action/experience leads to changes in the brain which lead to more complex actions which lead to more complex brain connections which lead to more complex actions, in a progressive cycle.
Major changes in the brain accompany major changes in behavior/skills in the second year, around 5-7 years, and at puberty.
Puberty involves complex physiological changes that lead to the ability to reproduce.
Puberty increases the differences between males and females.
Males and females go through similar changes during puberty, except for the changes that result directly from hormones produced by the gonads, which are different in the two sexes.
After pubertal changes are consolidated through adolescence, the young adult represents the peak of biological functioning.
Adult development involves gradually declining biological function, as well as transition from acute to chronic illnesses.
The concept of reserve capacity, or life maintenance reserve, is important for understanding the impact of illness, disease, accident, and abuse of one's body.
The rate of physical decline during adulthood is affected by many factors, including genes, accidents, injury, luck, environmental pollution, stress, nutrition, illness, bad habits, exercise, and temperament.
Maintaining life maintenance reserve involves: [1] keeping to a minimum the factors that accelerate decline, [2] taking care during periods of decline to prevent additional insult or stress, [3] focusing on recovery and rehabilitation to raise the reserve as high as possible.
Use it or lose it.
Menopause begins with gradual dis-coordination of the hormonal communication and regulation between the hypothalamus and pituitary.
Through adulthood, fewer ova are recruited to mature, and production of estrogen in the ovaries declines.
Reduction in estrogen and progesterone production contributes to the physiological changes that are part of the menopause processes.
Aerobic and resistance training can increase vital capacity, strength, and bone density at any age, even in late old age.
Death occurs when the cellular processes of the body, that began at conception, lose their integrity to such a degree that life cannot be maintained.




Cognitive Development


The mind is a phenomenon of a functioning brain.
The brain/mind has evolved to detect, process, and use information from the expectable environment, conveyed to it by the various sensory systems.
The brain incorporates specialized pathways for processing different types of information.
Intelligence refers to the ability to process and apply information/knowledge/understanding to solve problems, guide behavior, or adapt to new circumstances.
There are multiple ways to be intelligent, and people differ in their potential and development of each of the intelligences [Howard Gardner].
The development of the brain/mind and some differences among people are genetically governed.
As the brain develops, the ways information is processed changes.  Speed, efficiency, complexity, and ease and extent of coordination and integration of information all change across development.
Experience contributes to the development of specific functions of the brain, and differences in experience thus contribute to differences in knowledge/understanding/intelligences.
Early cognitive development is based on exercise of sensory-motor reflexes, which lead to exploration of the physical and social world and the development of patterns of familiar activity and experience [schemas].
Schemas gradually are differentiated, compared, integrated, and recombined to construct more complex actions, concepts, and understanding. 
Knowledge is constructed by the individual who makes meaning of his/her actions in the world.
The brain provides built-in pathways or systems for processing information acquired through experience and transforming it into concepts or knowledge that will be useful in adapting to the world as the child grows and behavior becomes more complex.
Information acquired through sensory-motor experience provides the basis for all later understanding [Piaget].
Language is constructed by the child as a system of symbolic reference to permit communication of ideas with others.
A major intellectual accomplishment of the early childhood years is developing language and constructing consistent grammar [rules] to communicate ideas effectively.
Each grammatical rule represents a specific way of expressing a specific aspect of experience or meaning [Chomsky].
The processes of differentiation and integration apply to concepts and relationships, as well as to the words and sentences used to refer to and communicate the concepts and relationships.
As schemas expand to become more complex, they evolve into orderly narrative sequences.
In middle childhood, children construct the elements of logic as they come to understand necessary relationships among things and concepts.  The schemas constructed to incorporate these necessary relationships become concrete mental operations.
Concrete operations allow the child to organize concepts into consistent categories and to think about and solve problems using the relationships among objects in different categories.
In adolescence, people develop a more sophisticated set of mental operations that permit constructing and thinking about abstract relationships [relationships that go beyond the actual experienced world].
Formal operations permit comparing and contrasting the abstract relationships one has constructed.
In adulthood, mental processes are further consolidated, coordinated, and applied to learning from new experience.
Like physical skills, intellectual skills that are exercised regularly continue to improve and are maintained, while those that are not used will become less available and efficient.
Use it or lose it.
Intellectual skills are affected by experience, health, education, socioeconomic status, social relationships, etc.
What people use their intellects for depends on what they need to understand, illustrating a transaction between the person and the context.
As the brain changes in adulthood, intellectual skills are likely to be affected.
Some intellectual changes and declines in later adulthood can be slowed by maintaining good physical health.
 






Psychosocial Development
Psychosocial development encompasses emotional development, self-concept, personality, the ways people use their bodies and minds in transactions with other people, interpersonal relationships, identity, and finding a place in the social contexts in which one participates.
Infants are born predisposed to attend to people and to participate in social transactions.
Emotions are physiological states evoked by particular situations.
As emotional expression develops, babies' relationships with others change.
Across development, people learn to understand and to express their emotional states and what triggers them, and how to think and act while experiencing strong emotions, both their own and those of other people.  [Bowen]
Babies differ in biologically-based temperament.  Temperament shapes the transactions babies have with caregivers.  Relationships involve temperaments of both baby and caregiver.
Attachments develop between caregivers and babies.
Attachment styles may have lasting implications for how people form and behave in relationships.
Most parents share the same goals for their children, but parents use different styles in trying to socialize their children.
Parenting styles represent different characteristic transactions between parent and child.  Children develop differently as they construct meaning from the transactions they have with parents using different parenting styles.
As they develop, children engage in an ever-increasing number and variety of relationships with significant other people.  Children learn different things in each of the variety of relationships they form.  [Sullivan]
Across the life span, people are engaged in a constant process of responding to and coping with [a] a constantly changing body and mind, and [b] a constantly changing social context of relationships, expectations, demands, and opportunities.  [Erikson]
The social contexts in which people engage have co-evolved with the human body and mind, so that the expectations and demands of the social community reflect the expectable changes and characteristics of the individual.  Development may be affected by the fit between the timing of the changes happening within the person and the timing of the changes in expectations happening in the social context.
Relationships with others are transactional, and development is affected by the changes taking place in people one is close with.
Psychosocial development continues across adulthood as the person encounters new relationships and roles and historic events and attempts to make sense of them, cope with them, and accommodate them into his/her life and identity.
As one goes through life, there is an inevitable dynamic change in the ratio between [a] the number and variety of people who feel responsible for you and who have known you since your birth, and [b] the number and variety of people whom you feel responsible for and whom you have known since their births.
Constructivist and transactional views of development are generally optimistic about the potential for change when development has been distorted.