INFANCY AND CHILDHOOD DEVELOPMENT PSYCHOLOGY
NATURE AND NURTURE
- nature the influence of our inherited characteristics on our personality, physical growth, intellectual growth, and social interactions.
- nurture the influence of the environment on personality, physical growth, intellectual growth, and social interactions.
Prenatal Period: Three Stages
The prenatal period extends from conception to birth and lasts about 266 days (around nine months). It consists of three successive phases: the germinal, embryonic, and fetal stages. During the prenatal period, a single cell will divide and grow to form 200 billion cells.
1.The germinal stage is the first stage of prenatal development and refers to the two-week period following conception. To understand how conception occurs, we need to backup a little and explain ovulation. Ovulation is the release of an ovum or egg cell from a woman’s ovaries.
If two separate ova are released and fertilized, the result is fraternal twins, who can be two brothers, two sisters, or a brother and sister. Because fraternal twins come from two separate eggs, they are no more genetically alike than any other two children of the same parents. In contrast, if a single ovum splits into two parts after fertilization, the result is identical twins, whose genes are almost indistinguishable.
Conception, or fertilization, occurs if one of the millions of sperm penetrates the ovum’s outer membrane. After the ovum has been penetrated by a single sperm its outer membrane changes and becomes impenetrable to the millions of remaining sperm.
Once the ovum has been fertilized, it is called a zygote, which is a single cell that is smaller than the dot in the letter i. The zygote begins a process of repeated division and, after about a week, consists of about 150 cells. After two weeks, it has become a mass of cells and attaches itself to the wall of the uterus. Once the zygote is implanted, or attached to the wall of the uterus, the embryonic stage begins.
2.Embryonic Stage
the organism begins to develop body organs.
The embryonic stage is the second stage of the prenatal period and spans the 2–8 weeks that follow conception; during this stage, cells divide and begin to differentiate into bone, muscle, and body organs.
At about 21 days after conception, the beginnings of the spinal cord and eyes appear; at about 24 days, cells differentiate to form what will become part of the heart; at about 28 days, tiny buds appear that will develop into arms and legs; and at about 42 days, features of the face take shape.
The organism has developed a number of body organs, such as the heart . The embryo is only about 4 cm long but already has the beginnings of major body organs and limbs and begins to look somewhat human (Cunningham et al., 2009).
3. The fetal stage: which is the third stage in prenatal development, begins two months after conception and lasts until birth.
During the fetal stage, the fetus develops vital organs, such as lungs, and physical characteristics that are distinctively human.
The placenta is an organ that connects the blood supply of the mother to that of the fetus. The placenta acts like a filter, allowing oxygen and nutrients to pass through while keeping out some toxic or harmful substances. However, certain viruses, such as HIV, and many drugs, including nicotine, caeine, marijuana, cocaine, and heroin, pass from the placenta into the fetus’s blood vessels and thus can affect
fetal development. These potentially dangerous agent are called teratogens.
A teratogen (teh-RAT-oh-gen) is any agent that can harm a developing fetus (causing deformities or brain damage). It might be a disease (such as genital herpes), a drug (such as alcohol), or another environmental agent (such as chemicals).
Birth defects and amniocentesis. During the fetal stage, a number of genetic errors can be tested for by amniocentesis (AM-nee-oh-sen-TEE-sis).
Amniocentesis, which is a medical test done between weeks 14 and 20 of pregnancy, involves inserting a long needle through the mother’s abdominal muscles into the amniotic fluid surrounding the fetus. By withdrawing and analyzing fetal cells in the fluid, doctors can identify a number of genetic problems.
One genetic problem identified by amniocentesis is Down syndrome . The risk for it increases in mothers who are in their forties (Cunningham et al., 2009).
Down syndrome results from an extra 21st chromosome and causes abnormal physical traits (a fold of skin at the corner of each eye, a wide tongue, heart defects) and abnormal brain development, resulting in degrees of mental retardation.
Fetal alcohol syndrome, or FAS, results from a mother drinking heavily during pregnancy, especially in the first 12 weeks. FAS results in physical changes, such as short stature, flattened nose, and short eye openings ; neurological changes, such as fewer brain connections within the brain structure; and psychological and behavioral problems, such as hyperactivity, impulsive behavior, deficits in information processing and memory, alcohol and drug use, and poor socialization.
Motor Development
Motor development refers to the stages of motor skills that all infants pass through as they acquire the muscular control necessary for making coordinated movements.
1 The proximodistal principle states that parts closer to the center of the infant’s body (proximo in Latin means “near”) develop before parts farther away (distal in Latin means “far”). For example, activities involving the trunk are mastered before activities involving the arms and legs. For that reason, infants can roll over before they can walk or bring their arms together to grasp a bottle.
2 The cephalocaudal principle states that parts of the body closer to the head (cephalo in Greek means “head”) develop before parts closer to the feet (caudal in Greek means “tail”).
Eg.- the head area (larger) developing before the feet area (smaller).
3 Maturation refers to developmental changes that are genetically or biologically programmed rather than acquired through learning or life experiences. eg- In developing motor skills , such as sitting up alone, crawling, and walking.
4 Parents often note the major milestones in their infants’ motor development, such as their first time crawling or walking, because they want to know if their children are within the developmental norms. Developmental norms refer to the average ages at which children perform various kinds of skills or exhibit abilities or behaviors.
By the age of 2, infants have grown into toddlers who can walk up and down stairs and use their hands to hold glasses of juice, operate toys, and, of course, get into a lot of trouble.
5 we have focused on the role of the genetic developmental program (nature), it’s important to remember that nature interacts with the environment (nurture) to encourage or discourage the development of various motor, sensory, and cognitive abilities (Hadders-Algra, 2002). For example, infants need appropriate environmental stimulation for development of their visual systems (see things), for learning to speak (hear parents speaking), for emotional development (get loving care), and for motor development (explore objects).
Emotional development refers to the influence and interaction of genetic factors, brain changes, cognitive factors, coping abilities, and cultural factors in the development of emotional behaviors, expressions, thoughts, and feelings (Goldsmith, 2003).
all infants, during the first two years the sextuplets developed a wide range of emotional expressions and feelings, including social smiling (age 4–6 weeks); anger, surprise, and sadness (age 3–4 months); fear (age 5–7 months); shame and shyness (age 6–8 months); and contempt and guilt (age 24 months) (Kopp & Neufeld, 2003).
We’ll focus on one of the genetic factors involved in emotional development, which is called temperament.
Temperament and Emotions
Temperament refers to relatively stable and long-lasting individual differences in mood and emotional behavior, which emerge early in childhood because these differences are largely influenced by genetic factors.
Researchers studied differences in infants’ temperaments by interviewing mothers with 2- to 3-month-old infants and then observing these same infants repeatedly over the next seven years. Researchers rated each infant on nine components of temperament, including activity level, attention span, fussiness, and mood. On the basis of these ratings, they divided infants into four categories (A. omas & Chess, 1977).
1 Easy babies: who made up 40% of the sample, were happy and cheerful, had regular sleeping and eating habits, and adapted quickly to new situations.
2 Slow-to-warm-up babies: who made up 15% of the sample, were more withdrawn, were moody, and tended to take longer to adapt to new situations.
3 Difficult babies : who made up 10% of the sample, were fussy, fearful of new situations, and more intense in their reactions. During the course of the seven-year study, difficult babies developed more serious emotional problems than the easy or slow-to-warm-up babies.
4 No-single-category babies: who made up 35% of the sample, had a variety of traits and could not be classified into one of the other three categories.
Genetic influence : Infants develop distinct temperaments very early, usually in the first 2–3 months of life, and these temperaments occur largely because of genetic factors rather than learning experiences (J. Bates, 2000).
Environmental influence : family influence, poverty level, and educational opportunities, all of which interact with and can change the infant’s initial temperament (Kagan 2003b).
Attachment is a close, fundamental emotional bond that develops between the infant and his or her parents or caregiver.
Separation anxiety : the infant develops a closer attachment to her parents, she also shows more distress when her parents leave; this is called separation anxiety. Separation anxiety is an infant’s distress—as indicated by loud protests, crying, and agitation—whenever the infant’s parents temporarily leave.
According to Ainsworth, separation anxiety is a clear sign the infant has become attached to one or both parents. By the end of the first year, an infant usually shows a close attachment to her parents as well as to one or more other family members. However, depending on the infant’s temperament (easy or difficult) and the mother’s attitude (caring or not responsive), different kinds of attachment occur.
Secure attachment is characteristic of infants who use their parent or caregiver as a safe home base from which they can wander off and explore their environments.
Insecure attachment is characteristic of infants who avoid or show ambivalence or resistance toward their parent or caregiver.
No comments:
Post a Comment