Chapter 11 Flashcards
what is development and what are the 4 stages?
- -development is the sequence of age-related changes that occur as a person progresses from conception to death (biological/behavioural/social and emotional)
(1) the prenatal period, between conception and birth, (2) childhood, (3) adolescence, and (4) adulthood
What is the prenatal period?
- -extends from conception to birth, usually encompassing nine months of pregnancy.
(1) the germinal stage (the first two weeks), (2) the embryonic stage (two weeks to two months), and (3) the fetal stage (two months to birth)
What is the germinal stage?
- first two weeks after conception. Begins when a zygote is created through fertilization.
- Within 36 hours cell division begins and the zygote becomes a microscopic mass of multiplying cells.
- Migrates along the mother’s fallopian tube to the uterine cavity and on about the seventh day, the cell mass begins to implant itself in the uterine wall. Many zygotes are rejected at this point.
- -During the implantation process, the placenta begins to form. The placenta is a structure that allows oxygen and nutrients to pass into the fetus from the mother’s bloodstream, and bodily wastes to pass out to the mother. Block the passage of blood cells, keeping the fetal and maternal bloodstreams separate.
What is the embryonic stage?
- -two weeks to two months
- -as cell division becomes more specialized, most of the vital organs and bodily systems begin to form in the developing organism, which is now called an embryo
- Arms, legs, hands, feet, fingers, toes, eyes, and ears are already discernible and beginning to look human
- -a period of great vulnerability because virtually all the basic physiological structures are being formed; Most miscarriages occur during this period and most major structural birth defects also result from problems that occur during the embryonic stage
What is the fetal stage?
- -two months through birth
- -muscles and bones begin to form and the developing organism, now called a fetus, becomes capable of physical movements as skeletal structures harden
- -Sex organs start to develop during the third month.
- -A layer of fat is deposited under the skin to provide insulation, and the respiratory and digestive systems mature (changes that ready the fetus for life outside the cosy, supportive environment of its mother’s womb)
- -the age of viability; 22-26 weeks the age at which a baby can survive in the event of a premature birth
- threshold of viability; 23 weeks and 25 weeks the age at which a baby can survive in the event of a premature birth. 23 weeks (20% survival) 25 weeks (67% survival)
What are terratogens?
–any external agents, such as drugs or viruses, that can harm an embryo or fetus
How can maternal drug use of heroin and cocaine affect developing fetus?
- -Babies of heroin users are born addicted to narcotics and have an increased risk of early death due to prematurity, birth defects, respiratory difficulties, and problems associated with their addiction
- -Prenatal exposure to cocaine is associated with increased risk of birth complications and a variety of cognitive deficits that are apparent in childhood
What is fetal alcohol syndrome disorder (FASD)?
- -a collection of congenital (inborn) problems associated with excessive alcohol use during pregnancy
- Typical problems include microcephaly (a small head), heart defects, irritability, hyperactivity, and delayed mental and motor development
- -most common known cause of intellectual disability and it is related to an increased incidence of difficulties in school, depression, suicide, drug problems, and criminal behaviour in adolescence and adulthood
How can tobacco/smoking affect a developing fetus?
- increase a mother’s risk for miscarriage, stillbirth, and prematurity, and new- borns’ risk for sudden infant death syndrome
- -Prenatal exposure to tobacco is also associated with slower than average cognitive development, attention deficits, hyperactivity, and conduct problems
How does maternal nutrition affect the developing fetus
- -Severe maternal malnutrition increases the risk of birth complications and neurological deficits for the newborn
- -Still, even when pregnant women have ample access to food, it is important for them to consume a balanced diet that includes essential vita- mins and minerals
- -Too much or too little weight gain during gestation is associated with a variety of birth complications, and guidelines for maternal weight gain are based on pre-pregnancy body mass index
- -maternal nutrition continues to affect the newborn during the breastfeeding period
How does stress and emotion affect the developing fetus?
- -elevated levels of prenatal stress have been found to be associated with increased stillbirths, impaired immune response, heightened vulnerability to infectious disease, slowed motor development, below-average, cognitive development, and social deficits
- stressful events can disrupt the delicate hormonal balance that fosters healthy prenatal development
How can maternal illness affect the developing fetus?
- -The placenta screens out quite a number of infectious agents, but not all
- -the nature of any damage depends, in part, on when the mother contracts the illness.
- -The transmission of AIDS can occur prenatally through the placenta, during delivery, or through breastfeeding
How can environmental toxins affect the developing fetus?
- prenatal exposure to air pollution has been linked to impairments in cognitive development at age five and increased obesity at age seven
- -exposure to the chemicals used in flame-retardant materials correlates with slower mental and physical development up through age six
How is fetal development linked to illness later in adulthood?
- -Evidence suggests that events during prenatal development can “program” the fetal brain in ways that influence the person’s vulnerability to various types of illness
- -prenatal malnutrition has been linked to vulnerability to schizophrenia, which usually emerges in late adolescence or early adulthood
- -Low birth weight has been found to be associated with an increased risk of heart disease many decades later in adulthood
- -Studies have also linked aspects of prenatal development to adults’ risk for depression and bipolar disorders as well as obesity, diabetes, and some types of cancer
What are the physical developments in childhood?
– Reflexes
•Some persist throughout life (coughing, blinking, yawning)
•Some weaken or disappear by 7 months (grasping, sucking, stepping (if you hold a baby up the feet will do a stepping motion), startle)
– motor & perceptual develop over time
• Perceptual development (connections between eyes/brain, and processing of visual stimuli is not fully developed) is tied to motor development – in that it requires adequate perception to be able to coordinate movement.
• As our brain (wiring) & perceptual skills improve, our motor abilities also improve
• Early motor development also depends in part on physical growth (maturation -gradual expression of genes) and infants’ ongoing exploration of the world
– Brain development
• At birth, the brain has minimal connections between neurons (dendrites are underdeveloped), the myelin encasing the neurons in the brain is not yet fully formed, and there are extra neurons
• Through the process of development, the dendrites grow to facilitate the connections between the neurons.
•The myelin develops to facilitate neural communication.
•The unused neurons die
What are developmental norms?
- indicate the median age at which individuals display various behaviours and abilities
- -developmental norms are group averages so variations from the average are entirely normal
How do cultural variations affect developmental norms?
- -the Kipsigis people of Kenya begin active efforts to train their infants to sit up, stand, and walk soon after birth. Thanks to this training, Kipsigis children achieve these developmental milestones (but not others) about a month earlier than babies in North America
- -In contrast, relatively slow motor development has been found in some cultures that discourage motor exploration. among the Aché, a nomadic people living in the rain forests of Paraguay, safety concerns dictate that chil- dren under three rarely venture more than a metre from their mothers, who carry them virtually every- where. As a result of these constraints, Aché children are delayed in acquiring a variety of motor skills and typically begin walking about a year later than other children
- -Nonetheless, the similarities across cultures in the sequence and timing of early motor development outweigh the differences which suggests that early motor development depends to a considerable extent on maturation
What is temperament?
refers to characteristic mood, activity level, and emotional reactivity
What is the difference between longitudinal design and cross-sectional design?
- -longitudinal design: investigators observe one group of participants repeatedly over a period of time
- -cross-sectional design: investigators compare groups of participants of differing age at a single point in time
- -For example, in a cross-sectional study, an investigator tracing the growth of chil- dren’s vocabulary might compare 50 six-year-olds, 50 eight-year-olds, and 50 ten-year-olds. In contrast, an investigator using the longitudinal method would assemble one group of 50 six-year-olds and measure their vocabulary at age six, again at age eight, and once more at age ten.
- -longitudinal positives; no cohort effect
- -longitudinal negatives; takes years to complete. Participants often drop out because they move away or lose interest which may produce misleading developmental trends.
- -cross-sectional positives; completed more quickly, easily, and cheaply than longitudinal studies
- -cross-sectional negatives: cohort effect
What are cohort effects?
–Cohort effects occur when differences between age groups are due to the groups growing up in different time periods
What is the longitudinal study of the development of temperament?
- well established by the time the infant is two to three months old”
- -The easy child – generally in a positive mood, has regular routines, adapts easily and not readily upset(40%)
- The slow-to-warm-up child – somewhat negative, less regular in their sleeping and eating with a low mood intensity, low activity level, low adaptability (they don’t get too worked up like the difficult child) (15%)
- The difficult child – reacts negatively, cries frequently, irregular routine, does not adapt (10%)
- The remaining 35 percent of the children showed mixtures of these three temperaments
- -According to Chess and Thomas, a child’s temperament at three months was a stable and fair predictor of the child’s temperament at age ten
- -Infants categorized as “difficult” developed more emotional problems requiring counselling than other children did
- -Individual differences in temperament appear to be influenced to a considerable degree by heredity
What is attachment and separation anxiety?
- -refers to the close, emotional bonds of affection that develop between infants and their caregivers
- -the first important attachment is usually with the mother, because in most cultures she is the principal caregiver, especially in the early years of life
- -infants’ attachment to their mothers is not instantaneous but by six to eight months of age, they show a preference for her and protest when separated from her
- -separation anxiety: emotional distress seen in many infants when they are separated from people with whom they have formed an attachment. Typically peaks at around 14 to 18 months and then begins to decline.
What was the study conducted on monkeys by Harry Harlow to study attachment theory?
- -Harlow removed monkeys from their mothers at birth and raised them in the laboratory with two types of artificial “substitute mothers.”
- -One type of artificial mother was made of terry cloth the could provide contact comfort and the other type of artificial mother was made of wire
- -Half of the monkeys were fed from a bottle attached to a wire mother and the other half were fed by a cloth mother
- -If reinforcement through feeding were the key to attachment, the frightened monkeys should have scampered off to the mother that had fed them. This was not the case. The young monkeys scrambled for their cloth mothers, even if they were not fed by them
What attachment theory did John Bowlby propose?
- -According to his view, infants are biologically programmed to emit behaviour (smiling, cooing, clinging, and so on) that triggers an affectionate, protective response from adults
- -Bowlby also asserted that adults are programmed by evolutionary forces to be captivated by this behaviour and to respond with warmth, love, and protection and these characteristics would be adaptive in terms of promoting children’s survival.
- -However, contemporary theorists point out that if parents expect to pass their genes on to future generations, they need to raise their offspring to reproductive age and help them develop the social maturity required for successful mating