Human Development PDF

UC-Psychology Department 10 Chapter 2 HUMAN DEVELOPMENT Human development is the process of how people change over time. Change takes two forms,...

UC-Psychology Department 10 Chapter 2 HUMAN DEVELOPMENT Human development is the process of how people change over time. Change takes two forms, quantitative and qualitative. Quantitative change is a change in the amount or number of something, such as weight and height- or the increase in the number of words, phrases, and sentences that a child uses. Qualitative change is change in kind, structure, substance, or organization, such as the nature of one’s intelligence – or a child’s development from a non-verbal infant to a child who understands and speaks language (Papalia, 1995). DETERMINANTS OF DEVELOPMENT Psychologists recognize that two essential factors influence human development. These factors are (1) heredity or nature and (2) environment or nurture. Scientific investigations have established that behavior is a product of the interaction of genetic endowments and the environmental conditions. Heredity provides the individual innate capabilities and potentials that can be developed and nurtured by environmental factors. In a way, our nature is our genetic gift, which gives us physical traits such as hair color, eye color, and form of the body. It does also determine the kinds of emotions and motivations we will experience, which can be endless. Any new emotion is not possible to experience unless there is change to our genetic material. So in a way, genes give us certain traits or behavior characteristics; but it’s all a matter of whether or not we carry out our certain inherited qualities. And our environment (nurture) can sometimes make that choice for us. The other side of the debate claims that nurture is the cause to our behavior as well as characteristics. Even though genes are what give us that certain spunk to our personality, the environment has the power to alter it and make us into the exact opposite, as some say. Even the way that certain children are brought up can change how they turn out. A. Heredity The developmental process starts with the genetic transmission of traits from the parents to offspring called heredity. The transmission of traits begins at conception when the sperm cell of the father unites with the egg cell of the mother through the process of fertilization to form a single cell called the zygote. The zygote is composed of the cytoplasm and the nucleus. The nucleus contains the genes, the basic hereditary units that transmit genetic characteristics from parents to the children. Some characteristics that are passed on by the parents to their children are physical traits, specific talents and skills, and some disorders. One of the most important findings in genetics research is that some genes are dominant and some are recessive. A dominant gene contains traits that will always occur when paired with UC-Psychology Department 11 any other gene. On the other hand, a recessive gene contains traits that will only occur when paired with another recessive gene. A dominant gene is a gene that is fully expressed in the phenotype (phenotype means appearance). Say you have two genes B = brown hair and b = blonde hair. More people have brown hair because the B gene is dominant to the b gene. These traits come in pairs like Bb. One gene will be expressed, in this case brown hair. If you ended up with two recessive genes like blonde hair (bb) then you'd be blonde! But there is less of a chance of this happening since it is recessive DOMINANT TRAITS RECESSIVE TRAITS eye coloring brown eyes grey, green, hazel, blue eyes Vision farsightedness nearsightedness normal vision night blindness normal vision color blindness* normal vision Hair dark hair blonde, light, red hair non-red hair red hair curly hair straight hair full head of hair baldness* widow's peak normal hairline facial features dimples no dimples unattached earlobes attached earlobes freckles no freckles broad lips thin lips appendages extra digits/polydactyly normal number fused digits normal digits short digits normal digits fingers lack 1 joint normal joints limb dwarfing normal proportion clubbed thumb normal thumb double-jointedness normal joints Other immunity to poison ivy susceptibility to poison ivy normal pigmented skin albinism normal blood clotting hemophilia* normal hearing congenital deafness normal hearing and speaking deaf mutism normal- no PKU phenylketonuria (PKU) * sex-linked characteristic http://www.blinn.edu/socialscience/ldthomas/feldman/handouts/0203hand.htm UC-Psychology Department 12 Chromosomes are the carriers of the genes. It can be seen under a microscope as a twisted string of odd sized and odd shaped beads in the nucleus of a cell. Each individual has 46 chromosomes that occur in pairs, thus human chromosomes are arranged in 23 pairs. Each pair of chromosomes looks exactly alike (XX) for the females and males except in pair no.23 of the male where they look different (XY). Pair no. 23 contains the sex-linked genes. There are two basic principles of heredity. The (1) principle of reproduction or principle of consistency states that “like produces like”, and the (2) principle of variation/variability says that “no two individuals are exactly alike”. Genetic Influences on Behavior Behavior genetics is a field that combines the methods of genetics and psychology to study the inheritance of behavioral tendencies. Researchers have devised a variety of methods for understanding the relationship between genetics and behavior. 1. Twin Studies. Studies on identical twins (those that develop from a single zygote hence they have the same genes) even if separated at birth revealed similar physical characteristics and behavioral tendencies. On the other hand, fraternal twins (those that develop from two separate zygotes hence they may have different set of genes) may not have the same physical traits and behavioral characteristics even if they are raised together. 2. Adoption Studies. Studies have shown that children who were adopted resemble more their biological parents even if they were raised by their adoptive parents. For example, children whose biological parents are alcoholic are at risk of becoming alcoholic themselves even if they are reared by adoptive parents who are not alcoholic. 3. Selective Breeding. This is a method of studying the inheritance of particular traits in animals. Selective breeding has been used to demonstrate the inheritance of a number of behavioral characteristics. For example, dogs have been bred to be excitable or lethargic. If a trait is influenced by heredity, it should be possible to change it through selective breeding. If selective breeding does not alter a trait, it is assumed that the trait is dependent primarily on environmental factors (Plomin, 1989; Atkinson, et. al. 1998). B. Environment As mentioned earlier, behavior is not determined by heredity alone. The environment plays a significant role in the development of behavior and personality. Genes provide the limits of the person’s potentials but what happens to such potentials depends on the environment where he or she grows up. Environment refers to non-genetic factors that influence an individual’s behavior and development. Environment includes all the many things in our surroundings that affect us directly and all the things that stimulate our sense organs. Examples of these are food, sounds, and the like. The UC-Psychology Department 13 influence of the environment can also be determined based on our interaction or absence of interaction with other people. Researchers found out children who were raised by animals in the forest without the presence of other human beings developed behaviors similar to the behaviors of animals that raised them. Furthermore, children who were isolated from other people at birth were found out to experience difficulty in establishing social relationships. STAGES OF DEVELOPMENT The individual passes through sequential stages in the process of development. The developmental stages are the divided into the prenatal stage and the post-natal stage. A. PRENATAL STAGE The prenatal Stage is referred to as the gestation period or the stage before birth. This period takes 9 months or 280 days between conception and birth. It is divided into three periods: the period of the zygote, the period of the embryo and the period of the fetus. 1. The period of the zygote is also called the germinal period. It starts from the moment of conception until the second week of life. After conception has occurred in the fallopian tube, the zygote will divide and multiply by itself forming a small mass of cells called the blastocyst. At about seven to ten days after conception, the blastocyst will travel from the fallopian tube to the uterus and eventually implants itself to its linings. After implantation, the blastocyst is now functionally attached to the mother. Ectopic pregnancy results if the blastocyst is unable to travel to the uterus but instead develops in the fallopian tube. The blastocyst is composed of three layers that soon develop into the different organs of the body. The ectoderm (outer layer) develops later into the epidermis, hair, teeth, sensory cells, and nervous system. The mesoderm (middle layer) subsequently develops into the dermis, muscles, skeleton, and the circulatory and excretory organs. The endoderm develops into the Eustachian tube, trachea, lungs, gastrointestinal tract linings, and the endocrine glands. 2. The period of the embryo starts from the second week to the third month of pregnancy. During this period, a rudimentary heart that beats, a brain, an intestinal tract, and other organs will be formed and developed. Although these organs are at a primitive stage of development, they are now clearly recognizable. Moreover, by the 8th week, the embryo is about an inch long, and has arms, legs, and a face that are discernible. Following the 8th week, the embryo faces a critical period, the first of several stages in prenatal development in which specific kinds of growth must occur if the individual is to develop normally. For example, if the eyes and ears do not develop during this stage, they will never be formed later on, and if they are formed abnormally, they will be permanently damaged. During critical periods, organisms are particularly sensitive to environmental influences such as the presence of certain drugs can have a devastating effect on subsequent development. UC-Psychology Department 14 3. The period of the fetus starts from the third month until birth. During this period, growth and development continue dramatically. At about 16 to 18 weeks (4 -5 mos.), movements become strong enough for the mother to sense the baby. Hair begins to grow in the baby’s head; facial features become similar to those the child will display at birth. The major organs begin to function, although the fetus could not be kept alive outside the mother. By the twenty-fourth week (6 mos.), the fetus has many characteristics it will display as a newborn. In fact, when an infant is born prematurely at this stage, it can open and close its eyes; suck; cry; look up, down, and around; and even grasp objects placed in its hands, although it is still unable to survive for long outside the mother. At about 28 weeks (7mos.), the fetus reaches the age of variability, the point at which it can survive if born prematurely. In the final weeks of pregnancy, the fetus continues to grow and gain weight, becoming increasingly fit. At the end of the normal thirty-eight weeks (9 mos.) of pregnancy, the fetus is ready to be born. Genetic Influences on the Fetus (Feldman, 1996; Holmes, 1991) Some abnormal traits were found to have hereditary basis. Some of the genetic abnormalities are the following: 1. Phenylketonuria (PKU). This is an inherited form of mental retardation due to a disorder of amino-acid metabolism. A child born with PKU cannot produce the enzyme that is needed to breakdown an amino acid called phenylalanine. The disease is treatable, however, if detected early. Children with this disorder can be placed on a special diet that allows them to develop normally. Children with this disorder are so retarded that they cannot walk or talk. They are also likely to be irritable, unpredictable, and hyperactive, and they are generally unresponsive to other persons. They often show aimless motor behavior such as arm waving, rocking, and unusual finger movements. 2. Sickle-cell anemia. This is a disorder caused by the abnormal shape of the victim’s red blood cells affecting mostly African-American people. Children with this disorder may have poor appetites, swollen stomachs, and yellowish eyes; they frequently die during childhood. 3. Tay-Sachs disease. This is a disorder characterized by the body’s inability to breakdown fats. It most often afflicts Jews of eastern European ancestry. Children afflicted with this disorder usually die by the age of 3 or 4. Other Genetic Abnormalities These disorders are brought about not by inherited trait but by mutation – a sudden genetic variation. They are departures from parent types caused by either a gene or chromosomal aberration. UC-Psychology Department 15 1. Down syndrome. This results from an extra chromosome added to the 21st pair. Hence, those afflicted with this kind of disorder have 47 chromosomes instead of the usual 46. People of this kind have round face and slanted eyes. Children with Down’s syndrome are typically retarded but are friendly and cheerful in interacting with other people. This disorder is also called mongolism. 2. Turners’s syndrome. This results from the loss of one X chromosome in pair number 23, hence, the person has only 45 chromosomes instead of the usual 46. People afflicted with this kind of disorder are females. These women have underdeveloped ovaries thus they are unable to produce offspring and are often mentally retarded. 3. Klinefelter syndrome. This results from an additional X chromosome in pair no. 23, hence, the person has 47 chromosomes instead of the usual 46. People afflicted with this kind of disorder are males. Men with this kind of disorder have underdeveloped testes, female-like breast and are mentally retarded. 4. XYY syndrome. This results from an additional Y chromosome in pair no. 23, hence, the person has 47 chromosomes instead of the usual 46. People afflicted with this kind of disorder are males. These men are unusually tall and found to have aggressive and violent tendencies. Prenatal Environmental Influences (Feldman, 1996) A number of environmental factors also have on effect on the course of fetal development. The major prenatal environmental influences are: a. Mother’s Nutrition. What a mother eats during pregnancy can have important implications on the baby’s health. Mothers who are seriously undernourished cannot provide adequate nutrition to the baby, and are likely to give birth to underweight babies. Poorly nourished babes are also more susceptible to disease, and lack of nourishment may have an adverse impact on mental development. b. Mother’s Illness. Rubella (German measles), if contacted by the mother during pregnancy results in prenatal death, blindness, deafness, and heart abnormalities. Other maternal diseases like syphilis, diabetes, high blood pressure, and acquired immunodeficiency syndrome (AIDS) result in mental retardation, physical deformities, miscarriages, or growth failure. c. Drugs. Some drugs, if taken in by the pregnant woman, can have tragic effect on the unborn child. Thalidomide, a tranquilizer, causes severe deformities such as the absence of limbs. Alcohol causes mental retardation, low birth weight, small head, and limb deformities. Nicotine causes premature birth and low birth weight and length. Other physically addictive drugs, like cocaine, if taken in by the mother, causes permanent physical and mental impairment. Moreover, newborns suffer painful withdrawal symptoms after birth UC-Psychology Department 16 d. Radiation. Exposure of the mother to radioactive materials, including x-rays, during pregnancy results in physical deformities and mental retardation on the part of the baby. e. Mother’s Age. Giving birth at a young age (mother’s age is below 18 at birth of child), results in premature delivery and an increased incidence of Down syndrome. Giving birth at an age older than 35 also results in an increased incidence of Down syndrome. f. Mother’s Emotion. Mothers who are happy at becoming pregnant tend to be more affectionate to their children than those not expressing pleasure at pregnancy. Moreover, it is claimed that mothers who are anxious and tense during the last months of their pregnancy are more apt to have children who are irritable and who sleep and eat poorly. It is believed that this is caused by increased sensitivity of the autonomic nervous system of the fetus as a result of the chemical changes produced by the mother’s emotional state. Techniques Used to Diagnose Fetal Problems (Dacey and Travers, 1998) When a prenatal problem is suspected, diagnostic procedures are necessary. Among the diagnostic tools now being used are the following: a. Amniocentesis. This is a technique that entails inserting a needle through the mother’s abdomen piercing the amniotic sac. The sample fluid provides information about the child’s sex and some chromosomal abnormalities. Amniocentesis may be done from the 15th week of pregnancy onwards. b. Fetoscopy. A tiny instrument inserted into the amniotic cavity making it possible to see the fetus. If the view is clear, defects of hand and legs are visible. Fetoscopy is often performed after the 16th week of pregnancy. c. Ultrasound. A technique that uses waves to produce an image that enables a physician to detect structural abnormalities. Useful pictures can be obtained as early as 7 weeks. Ultrasound is often used in conjunction with other techniques like amniocentesis and fetoscopy. B. POST NATAL DEVELOPMENT 1. Infancy. This stage covers the first two weeks of life immediately after birth. This is a period of major adjustment as the infant is already physically separated from the mother. The infant is very helpless and depends on others for his or her survival. 2. Babyhood. This stage starts from the 2nd week to the 2nd year of life. In this stage, there is rapid growth, decrease in helplessness as the baby learns to be more independent in his movements. As the baby passes through this stage, he starts to learn how to sit, stand, crawl, walk and speak. A sense of self- awareness also starts to develop. UC-Psychology Department 17 3. Early Childhood. This stage covers the 2nd year to the 6th year of life. This is known to be the “questioning stage” as the child begins to become curious and tends to ask questions about anything that catches his attention. This is also a period when the child starts to be difficult to deal with because of temper tantrums and other forms of emotional outbursts. This is also the “preschool age” because it precedes the time that the child is supposed to attend formal schooling. 4. Late Childhood. This stage starts from the 6th year of life until the age of puberty. This period is called the “gang age” as the child starts to socialize with other children of his own age and gender. This is also the start of formal schooling as the child is expected to attend elementary school. This is also known as the “smart age” as the child thinks he knows everything and does not hesitate to inform the others of his knowledge. 5. Puberty. The puberty stage overlaps the later period of late childhood and adolescence. This is a period characterized by changes in the physical body of the individual brought about by the activation of the gonads that produces the sex hormones. 6. Adolescence. This stage starts after puberty and ends at about age eighteen (18). Psychologists claim that this is a period of emotional instability and identity crisis. It is characterized by aggressiveness, awkwardness of movements and curiosity about sex. Towards the end of this stage, the individual starts to become more emotionally stable and starts to assume legal and social responsibilities. 8. Early Adulthood. This period covers the period after 18 years old to approximately 40. This stage is characterized by three adjustments: adjustment to work, adjustment to marriage, and adjustment to parenthood. The body has developed more proportionately and movements become more refined. 9. Middle Adulthood. This stage starts from age 40 to 60 in the life span. This is the peak period in life not only for financial and social success but also for authority and prestige. It is said that the degree of success of the individual has reached in this stage will determine how happy he will be in the later periods of his life. 10. Late Adulthood. This period starts from age 60 onwards. This is marked by physical and mental deterioration that accompany the cessation of the reproductive capacities for both THEORIES OF DEVELOPMENT PSYCHOSOCIAL THEORY (E. ERIKSON) For each stage of development some kind of psychosocial crisis is likely to occur. If a person is provided with a social and psychological environment that is conducive to development, he will be able to deal adequately with the crisis and problems with each stage. If he fails to develop the strengths and skills needed at each stage, he will subsequently find difficulty in dealing with psych crises in the succeeding stages of development.  UC-Psychology Department 18 Stage/age Psychosocial Significant Psychosocial Positive Negative crisis relations modalities Resolution Resolution I To get, Infant trust vs mistrust mother to give in return, hope, faith fear 0 – 18 months II autonomy vs parents to hold on, to will, impulsivity Toddler shame and let go determination self-doubt 18 mos. – 3yrs doubt III initiative vs guilt family to go after, to purpose, Feeling Preschooler play courage unworthy 3-6yrs IV industry vs neighborhood to complete, to competence inferiority school-age inferiority and school make things child together 6-12yrs V ego-identity vs peer groups to be oneself to fidelity, loyalty, uncertainty Adolescence role- confusion role models share oneself identity 12-18yrs VI intimacy vs partners, to lose and find love Promiscuity young adult isolation friends oneself in Self-absorption another isolation 18-24 VII generatively vs household to make be, to care Self-indulgence middle adult self- absorption workmates take care of 25-54 VII integrity vs mankind or to be through wisdom despair old adult despair my kind" having been, to 54 +++ face not being COGNITIVE THEORY (Jean Piaget) STAGE PERIOD CHARACTERISTICS ADULT BEHAVIORS Sensorimotor Birth – 2 years Coordination of sensory Emphasis on immediacy of input feelings, inability to attend Development of object to consequences. The permanence “here and now” is all. Pre-operational 2 – 7 years Development of symbolic Belief in intuition, magical thought thinking, fantasies are Irreversible, egocentric real. Superstitions abound thinking Magical thinking  UC-Psychology Department 19 Concrete 7 – 11 years Mental operations applied emphasizing facts, Operational to concrete objects and routines; only one way to events do things. Never vary any Development of routine in spite of conservation, mastery of changed circumstances. concept of reversibility Formal Operations 11 years and Development of logical and above systematic thinking and using them in the abstract, rather than the concrete. “hypothetical thinking” PSYCHOSEXUAL DEVELOPMENT (Sigmund Freud) Theoretical Relationship between Freud's Psychosexual Stages And Personality Characteristics FOCUS OF SATISFYING OUTCOME OF CONSEQUENCES OF STAGES LIBIDO BEHAVIORS GRATIFICATION FIXATION Mouth Sucking Trust gullibility, passivity Early oral swallowing oral o ptimism oral pessimism, Late oral Mouth biting, chewing independence manipulativeness, sarcasms Early anal Anus Expulsion of feces Self-control obstinacy, cruelty, messiness retention of mastery conscientiousness, Late anal anus feces punctuality, cleanliness sexual curio sity, sexual identity, Genital self- superego problems with Phallic organs examination, fo rmation authority figures, and (healthy sexual manipul ation conscience) maladjustme nt Latency --- --- --- --- Genital sexual intercourse, Capacity for organs intimacy, unselfish love, Ge nital sublimation in work fulfilling work, and art delay of gratification  UC-Psychology Department 20 MORAL DEVELOPMENT THEORY (Lawrence Kohlberg)  LEVEL ONE: Stage 1: Punishment and Obedience Orientation Pre- * Moral thinking is based on punishment conventional * Children obey because adults tell them to obey Reasoning Stage 2: Individualism and Purpose * Moral thinking is based on rewards and self-interest * Children obey when they want to obey and when it is in their best interest * What feels right is what feels good and what is rewarding  LEVEL TWO: Stage 3: Interpersonal Norms. Conventional * Individual values trust, caring and loyalty to others as the basis of moral Reasoning judgment * Children often adopt their parent’s moral standards, seeking to be taught of by their parents as a “good girl or good boy” Stage 4: Social System Morality * Moral judgments are based on understanding the social order, law, justice and duty The rules of the society are the bases for right and wrong, and doing one's duty and showing respect for authority are important.  LEVEL THREE: Stage 5: social contract stage Post The person at this level sees morality as a matter of entering into a rational Conventional contract with one's fellow human beings to be kind to each other, respect Reasoning authority, and follow laws to the extent that they respect and promote those universal values. Social contract morality often involves a utilitarian approach, where the relative value of an act is determined by "the greatest good for the greatest number." Stage 6: Universal Ethical Principles * Individuals have developed a moral standard based on universal human rights * When faced with a conflict between law and conscience, the individual will follow conscience, even though the decision might involve personal risk At this point, the person makes a personal commitment to universal principles of equal rights and respect, and social contract takes a clear back- seat: If there is a conflict between a social law or custom and universal principles, the universal principles take precedence.