Developmental Psychology PDF

DEVELOPMENTAL PSYCHOLOGY I. INTRODUCTION TO DEVELOPMENTAL PSYCHOLOGY Developmental Psychology also known as Human Development or Lifespan Development, is the scientific study of ways in which people change, as well as stay the same, from conce...

DEVELOPMENTAL PSYCHOLOGY I. INTRODUCTION TO DEVELOPMENTAL PSYCHOLOGY Developmental Psychology also known as Human Development or Lifespan Development, is the scientific study of ways in which people change, as well as stay the same, from conception to death. This includes physical and other psychophysiological processes, cognition, language, and psychosocial development, including the impact of family and peers. Lifespan Perspective Paul Baltes identified several underlying principles of the lifespan perspective. 1. Development is lifelong. Lifespan theorists believe that development is life- long, and change is apparent across the lifespan. No single age period is more crucial, characterizes, or dominates human development. 2. Development is multidirectional. Humans change in many directions. We may show gains in some areas of development, while showing losses in other areas. Every change, whether it is finishing high school, getting married, or becoming a parent, entails both growth and loss. 3. Development is multidimensional. We change across three general domains/dimensions; physical, cognitive, and psychosocial. The physical domain includes changes in height and weight, sensory capabilities, the nervous system, as well as the propensity for disease and illness. The cognitive domain encompasses the changes in intelligence, wisdom, perception, problemsolving, memory, and language. The psychosocial domain focuses on changes in emotion, selfperception and interpersonal relationships with families, peers, and friends. It is also important to note that a change in one domain may cascade and prompt changes in the other domains. 4. Development is multidisciplinary. Human development is such a vast topic of study that it requires the theories, research methods, and knowledge base of many academic disciplines. 5. Development is characterized by plasticity. Plasticity is all about our ability to change and that many of our characteristics are malleable. For instance, plasticity is illustrated in the brain’s ability to learn from experience and how it can recover from injury. 6. Development is multicontextual. Development occurs in many contexts. Baltes (1987) identified three specific contextual influences: a) Normative age-graded influences: An age-grade is a specific age group, such as toddler, adolescent, or senior. Humans in a specific age-grade share particular experiences and developmental changes. b) Normative history-graded influences: The time period in which you are born shapes your experiences. A cohort is a group of people who are born at roughly the same period in a particular society. These people travel through life often experiencing similar circumstances. c) Non-normative life influences: Despite sharing an age and history with our peers, each of us also has unique experiences that may shape our 1  DEVELOPMENTAL PSYCHOLOGY development. A child who loses his/her parent at a young age has experienced a life event that is not typical of the age group. Socioeconomic status (SES) is a way to identify families and households based on their shared levels of education, income, and occupation. Poverty level is an income amount established by the government that is based on a set of income thresholds that vary by family size. If a family’s income is less than the government threshold, that family is considered in poverty. Culture is the totality of our shared language, knowledge, material objects, and behavior. It includes ideas about what is right and wrong, what to strive for, what to eat, how to speak, what is valued, as well as what kinds of emotions are called for in certain situations. Ethnocentrism - belief that our own culture is superior and is a normal byproduct of growing up in a culture. It becomes a roadblock, however, when it inhibits understanding of cultural practices from other societies. Cultural relativity - appreciation for cultural differences and the understanding that cultural practices are best understood from the standpoint of that particular culture. Lifespan vs. Life expectancy Lifespan or longevity, refers to the length of time a species can exist under the most optimal conditions. For instance, the grey wolf can live up to 20 years in captivity, the bald eagle up to 50 years, and the Galapagos tortoise over 150 years. The longest recorded lifespan for a human was Jean Calment who died in 1994 at the age of 122 years, 5 months, and 14 days (Guinness World Records, 2016). Life expectancy is the predicted number of years a person born in a particular time period can reasonably expect to live. Conceptions of Age The number of years since your birth, or what is called your chronological age. So years since birth is not the only way we can conceptualize age. Biological age: Another way developmental researchers can think about the concept of age is to examine how quickly the body is aging, this is your biological age. Several factors determine the rate at which our body ages. Our nutrition, level of physical activity, sleeping habits, smoking, alcohol consumption, how we mentally handle stress, and the genetic history of our ancestors, to name but a few. Psychological age: Our psychologically adaptive capacity compared to others of our chronological age is our psychological age. This includes our cognitive capacity along with our emotional beliefs about how old we are. An individual who has cognitive impairments might be 20 years of age, yet has the mental capacity of an 8-year-old. A 70- year-old might be travelling to new countries, taking courses at college, or starting a new business. Social age: Our social age is based on the social norms of our culture and the expectations our culture has for people of our age group. 2  DEVELOPMENTAL PSYCHOLOGY II. PERIODS OF DEVELOPMENT 1. Prenatal Development: Conception occurs and development begins. All of the major structures of the body are forming, and the health of the mother is of primary concern. Understanding nutrition, teratogens, or environmental factors that can lead to birth defects, and labor and delivery are primary concerns. 2. Infancy and Toddlerhood: The first two years of life are ones of dramatic growth and change. A newborn, with a keen sense of hearing but very poor vision, is transformed into a walking, talking toddler within a relatively short period of time. Caregivers are also transformed from someone who manages feeding and sleep schedules to a constantly moving guide and safety inspector for a mobile, energetic child. 3. Early Childhood: This period is also referred to as the preschool years and consists of the years which follow toddlerhood and precede formal schooling. As a two to six-year-old, the child is busy learning language, is gaining a sense of self and greater independence, and is beginning to learn the workings of the physical world. 4. Middle and Late Childhood Starts at six years of age and continues until the onset of puberty comprise middle and late childhood, and much of what children experience at this age is connected to their involvement in the early grades of school. 5. Adolescence: Adolescence is a period of dramatic physical change marked by an overall growth spurt and sexual maturation, known as puberty. It is also a time of cognitive change as the adolescent begins to think of new possibilities and to consider abstract concepts such as love, fear, and freedom. Ironically, adolescents have a sense of invincibility that puts them at greater risk of dying from accidents or contracting sexually transmitted infections that can have lifelong consequences. 6. Emerging Adulthood: The period of emerging adulthood is a transitional time between the end of adolescence and before individuals acquire all the benchmarks of adulthood. Continued identity exploration and preparation for full independence from parents are demonstrated. Although at one’s physiological peak, emerging adults are most at risk for involvement in violent crimes and substance abuse. 3  DEVELOPMENTAL PSYCHOLOGY 7. Early Adulthood: The twenties and thirties are identified as early adulthood. Intimate relationships, establishing families, and work are primary concerns at this stage of life. 8. Middle Adulthood: The forties through the mid-sixties is referred to as middle adulthood. This is a period in which aging becomes more noticeable and when many people are at their peak of productivity in love and work. 9. Late Adulthood: Late adulthood is sometimes subdivided into two categories: The young-old who are from 65-84 years and the oldest-old who are 85 years and older. One of the primary differences between these groups is that the young-old are still relatively healthy, productive, active, and the majority continue to live independently. 4  DEVELOPMENTAL PSYCHOLOGY Issues in Developmental Psychology 1. Nature and Nurture: For any particular feature, those on the side of nature would argue that heredity plays the most important role in bringing about that feature. Those on the side of nurture would argue that one's environment is most significant in shaping the way we are. 2. Continuity versus Discontinuity: Stage theories or discontinuous development assume that developmental change often occurs in distinct stages that are qualitatively different from each other, and in a set, universal sequence. At each stage of development, children and adults have different qualities and characteristics. Information processing theorists, assume development is a more slow and gradual process known as continuous development. For instance, they would see the adult as not possessing new skills, but more advanced skills that were already present in some form in the child. Brain development and environmental experiences contribute to the acquisition of more developed skills. 3. Active versus Passive: Some theorists see humans as playing a much more active role in their own development. Piaget, for instance believed that children actively explore their world and construct new ways of thinking to explain the things they experience. In contrast, many behaviorists view humans as being more passive in the developmental process. 4. Stability versus Change: Some theorists argue that the personality traits of adults are rooted in the behavioral and emotional tendencies of the infant and young child. Others disagree, and believe that these initial tendencies are modified by social and cultural forces over time. Historical Theories on Development 1. Preformationist View: Preformationism, or the belief that a tiny, fully formed human is implanted in the sperm or egg at conception and then grows in size until birth, was the predominant early theory. Children were believed to possess all their sensory capabilities, emotions, and mental aptitude at birth, and as they developed these abilities unfolded on a predetermined schedule. The environment was thought to play no role in determining development. 2. John Locke (1632-1704): a British philosopher, refuted the idea of innate knowledge and instead proposed that children are largely shaped by their social environments, especially their education as adults teach them important knowledge. He believed that through education a child learns socialization, or what is needed to be an appropriate member of society. Locke advocated thinking of a child’s mind as a tabula rasa or blank slate, and whatever comes into the child’s mind comes from the environment. 3. Jean-Jacques Rousseau (1712-1778): Like Locke, Rousseau also believed that children were not just little adults. However, he did not believe they were blank slates, but instead developed according to a natural plan which unfolded in different stages (Crain, 2005). He did not believe in teaching them the correct way to think, but believed children should be allowed to think by themselves according to their own ways and an inner, biological timetable. This focus on 5  DEVELOPMENTAL PSYCHOLOGY biological maturation resulted in Rousseau being considered the father of developmental psychology. 4. Arnold Gesell (1880-1961): He studied the neuromotor development of children. Gesell believed that the child’s development was activated by genes and he called this process maturation. Further, he believed that development unfolded in fixed sequences, and he opposed efforts to teach children ahead of schedule as he believed they will engage in behaviors when their nervous systems had sufficiently matured. 5. Psychoanalysis: Sigmund Freud emphasized the importance of early childhood experiences in shaping our personality and behavior. In our natural state, we are biological beings and are driven primarily by instincts. During childhood, however, we begin to become social beings as we learn how to manage our instincts and transform them into socially acceptable behaviors. 6. Psychosocial Theory: Erik Erikson presents eight developmental stages that encompass the entire lifespan. According to Erikson, successful development involves dealing with and resolving the goals and demands of each of these psychosocial crises in a positive way. These crises are usually called stages, although that is not the term Erikson used. If a person does not resolve a stage successfully, it may hinder their ability to deal with later stages. However, most individuals are able to successfully complete the eight stages of his theory. 7. Learning Theory: Also known as Behaviorism, is based on the premise that it is not possible to objectively study the mind, and therefore psychologists should limit their attention to the study of behavior itself. The most famous behaviorist was Burrhus Frederick (B. F.) Skinner. He used the ideas of stimulus and response, along with the application of rewards or reinforcements. 8. Social Learning Theory was developed by Albert Bandura (1977). His theory calls our attention to the ways in which many of our actions are not learned through conditioning, as suggested by Skinner. 9. Bandura (1986) suggests that there is interplay between the environment and the individual. We are not just the product of our surroundings, rather we influence our surroundings. There is interplay between our personality and the way we 6  DEVELOPMENTAL PSYCHOLOGY interpret events and how they influence us. This concept is called reciprocal determinism. 10. Cognitive Theory: The cognitive theories focus on how our mental processes or cognitions change over time. Three important theories are Jean Piaget’s, Lev Vygotsky’s, and Information-processing. 11. Jean Piaget (1896-1980). He was inspired to explore children’s ability to think and reason by watching his own children’s development. He was one of the first to recognize and map out the ways in which children's intelligence differs from that of adults (Piaget, 1929). He became interested in this area when he was asked to test the IQ of children and began to notice that there was a pattern in their wrong answers. He believed that children's intellectual skills change over time and that maturation, rather than training, brings about that change. II. HEREDITY, PRENATAL AND BIRTH A. HEREDITY Nature refers to the contribution of genetics to one’s development. The basic building block of the nature perspective is the gene. GENES - are specific sequence of nucleotides and are recipes for making proteins. Genotype refers to the sum total of all the genes a person inherits. Phenotype refers to the features that are actually expressed. Monozygotic or identical twins occur when a fertilized egg splits apart in the first two weeks of development. Dizygotic or fraternal twins two eggs or ova are released and fertilized by two separate sperm. GENETIC DISORDERS: Recessive Disorders (Homozygous): The individual inherits a gene change from both parents. If the gene is inherited from just one parent, the person is a carrier and does not have the condition. Sickle Cell Disease (SCD) is a condition in which the red blood cells in the body are shaped like a sickle (like the letter C) and affect the 7  DEVELOPMENTAL PSYCHOLOGY ability of the blood to transport oxygen. Carriers may experience some effects, but do not have the full condition. Cystic Fibrosis (CF) is a condition that affects breathing and digestion due to thick mucus building up in the body, especially the lungs and digestive system. In CF, the mucus is thicker than normal and sticky. Phenylketonuria (PKU) is a metabolic disorder in which the individual cannot metabolize phenylalanine, an amino acid. Left untreated intellectual deficits occur. PKU is easily detected and is treated with a special diet. Tay Sachs Disease is caused by enzyme deficiency resulting in the accumulation of lipids in the nerve cells of the brain. This accumulation results in progressive damage to the cells and a decrease in cognitive and physical development. Death typically occurs by age five. Albinism is when the individual lacks melanin and possesses little to no pigment in the skin, hair, and eyes. Vision problems can also occur. Autosomal Dominant Disorders (Heterozygous): In order to have the disorder, the individual only needs to inherit the gene change from one parent. Huntington’s Disease is a condition that affects the individual’s nervous system. Nerve cells become damaged, causing various parts of the brain to deteriorate. The disease affects movement, behavior and cognition. It is fatal, and occurs at midlife. Tourette Syndrome is a tic disorder which results in uncontrollable motor and vocal tics as well as body jerking. Achondroplasia is the most common form of disproportionate short stature. The individual has abnormal bone growth resulting in short stature, disproportionately short arms and legs, short fingers, a large head, and specific facial features. Sex-Linked Disorders: When the X chromosome carries the mutated gene, the disorder is referred to as an X-linked disorder. Males are more affected than females because they possess only one X chromosome without an additional X chromosome to counter the harmful gene. Fragile X Syndrome occurs when the body cannot make enough of a protein it needs for the brain to grow and problems with learning and behavior can occur. Fragile X syndrome is caused from an abnormality in the X chromosome, which then breaks. If a female has fragile X, her second X chromosome usually is healthy, but males with fragile X don’t have a second healthy X chromosome. This is why symptoms of fragile X syndrome usually are more serious in males. CHROMOSOMAL DISORDERS: Autosomal Chromosome Disorders - The individual inherits too many or two few chromosomes. Down Syndrome/Trisomy 21 is caused by an extra chromosome 21 and includes a combination of birth defects. Affected individuals have 8  DEVELOPMENTAL PSYCHOLOGY some degree of intellectual disability, characteristic facial features, often heart defects, and other health problems. The severity varies greatly among affected individuals. Trisomy 13 is caused by an extra chromosome 13. Affected individuals have multiple birth defects and generally die in the first weeks or months of life. Trisomy 18 is caused by an extra chromosome 18 and the affected individual also has multiple birth defects and early death. Sex-Linked Chromosomal Disorders: The disorder occurs on chromosome pair #23 or the sex chromosomes. Turner Syndrome is caused when all or part of one of the X chromosomes is lost before or soon after conception due to a random event. The resulting zygote has an XO composition. Turner Syndrome affects cognitive functioning and sexual maturation in girls. Infertility and a short stature may be noted. Klinefelter Syndrome is caused when an extra X chromosome is present in the cells of a male due to a random event. The Y chromosome stimulates the growth of male genitalia, but the additional X chromosome inhibits this development. The male can have some breast development, infertility, and low levels of testosterone. Genetic Counseling: A service that assists individuals identify, test for, and explain potential genetic conditions that could adversely affect themselves. The common reasons for genetic counseling include: Family history of a genetic condition Membership in a certain ethnic group with a higher risk of a genetic condition Information regarding the results of genetic testing, including blood tests, amniocentesis, or ultra sounds Learning about the chances of having a baby with a genetic condition if the parents are older, have had several miscarriages, have offspring with birth defects, experience infertility, or have a medical condition Behavioral Genetics is the scientific study of the interplay between the genetic and environmental contributions to behavior. 1. Genotype-Environment Correlations refer to the processes by which genetic factors contribute to variations in the environment. Passive genotype-environment correlation occurs when children passively inherit the genes and the environments their family provides Evocative genotype-environment correlation refers to how the social environment reacts to individuals based on their inherited characteristics. Active genotype-environment correlation occurs when individuals seek out environments that support their genetic tendencies. 9  DEVELOPMENTAL PSYCHOLOGY 2. Genotype-Environment Interactions involve genetic susceptibility to the environment. For instance, Adoption studies provide evidence for genotype-environment interactions. 3. Epigenetics studies modifications in DNA that affect gene expression and are passed on when the cells divide. Environmental factors, such as nutrition, stress, and teratogens are thought to change gene expression by switching genes on and off. B. PRENATAL DEVELOPMENT Prenatal development is divided into three periods: The germinal period, the embryonic period, and the fetal period. 1. The Germinal Period The germinal period (about 14 days in length) lasts from conception to implantation of the fertilized egg in the lining of the uterus. During this time, the organism begins cell division through mitosis. Blastocyst - after five days of mitosis there are 100 cells. The blastocyst consists of both an inner and outer group of cells. The inner group of cells, or embryonic disk will become the embryo The outer group of cells, or trophoblast, becomes the support system which nourishes the developing organism. 2. The Embryonic Period Starting the third week the blastocyst has implanted in the uterine wall. Upon implantation this multi-cellular organism is called an embryo. Now blood vessels grow forming the placenta. The placenta 10  DEVELOPMENTAL PSYCHOLOGY is a structure connected to the uterus that provides nourishment and oxygen from the mother to the developing embryo via the umbilical cord. Growth during prenatal development occurs in two major directions: a. from head to tail called cephalocaudal development and b. from the midline outward referred to as proximodistal development. 3. The Fetal Period From the ninth week until birth, the organism is referred to as a fetus. By the third month, the fetus has all its body parts including external genitalia. In the following weeks, the fetus will develop hair, nails, teeth and the excretory and digestive systems will continue to develop. The fetus is about 3 inches long and weighs about 28 grams. The first chance of survival outside the womb , known as the age of viability is reached at about 24 weeks Factors influencing prenatal risks: There are several considerations in determining the type and amount of damage that might result from exposure to a particular teratogen (Berger, 2005). These include: 11  DEVELOPMENTAL PSYCHOLOGY The timing of the exposure: Structures in the body are vulnerable to the most severe damage when they are forming. If a substance is introduced during a particular structure's critical period (time of development), the damage to that structure may be greater. For example, the ears and arms reach their critical periods at about 6 weeks after conception. If a mother exposes the embryo to certain substances during this period, the arms and ears may be malformed. The amount of exposure: Some substances are not harmful unless the amounts reach a certain level. The critical level depends in part on the size and metabolism of the mother. The number of teratogens: Fetuses exposed to multiple teratogens typically have more problems than those exposed to only one. Genetics: Genetic make-up also plays a role on the impact a particular teratogen might have on the child. This is suggested by fraternal twins exposed to the same prenatal environment, but they do not experience the same teratogenic effects. The genetic make-up of the mother can also have an effect; some mothers may be more resistant to teratogenic effects than others. Being male or female: Males are more likely to experience damage due to teratogens than are females. It is believed that the Y chromosome, which contains fewer genes than the X, may have an impact. C. BIRTH One of the most common methods for preparing for childbirth is The Lamaze Method. The emphasis of this method is on teaching the woman to be in control in the process of delivery. Muscle relaxation, breathing though contractions, having a focal point during contractions. 12  DEVELOPMENTAL PSYCHOLOGY Stages of Birth for Vaginal Delivery 13  DEVELOPMENTAL PSYCHOLOGY 1. The First Stage of labor begins with uterine contractions that may initially last about 30 seconds and be spaced 15 to 20 minutes apart. Some women experience false labor or Braxton-Hicks contractions, especially with the first child. 2. The Second Stage involves the passage of the baby through the birth canal. This stage takes about 10-40 minutes. At this stage, an episiotomy or incision made in the tissue between the vaginal opening and anus, may be performed to avoid tearing the tissue of the back of the vaginal opening. 3. The Third Stage is relatively painless. During this stage, the placenta or afterbirth is delivered. This is typically within 20 minutes after delivery. If an episiotomy was performed it is stitched up during this stage. Problems of the New Born: 1. Anoxia is a temporary lack of oxygen to the brain. Difficulty during delivery may lead to anoxia which can result in brain damage or in severe cases, death. Babies who suffer both low birth weight and anoxia are more likely to suffer learning disabilities later in life as well. 2. Low Birth weight: We have been discussing a number of teratogens associated with low birth weight such as alcohol, tobacco, if he or she weighs less than 5 pounds 8 ounces. 3. Preterm: A newborn might also have a low birth weight if it is born at less than 37 weeks gestation, which qualifies it as a preterm baby 4. Small-for-Date Infants: Infants that have birth weights that are below expectation based on their gestational age. Postpartum Maternal Concerns: 1. Baby blues are feelings of sadness that occur 3 to 5 days after having a baby, and typically disappear usually within 10 days of the birth. 2. Peripartum onset of depression, also known as postpartum depression, is a type of depression that occurs during pregnancy or in the 4 weeks following pregnancy. 14