Lifespan Development

Lifespan Development Psychology 2012 – Fall 2004

Introduction: Your Life Story • Developmental Psychology – branch of psychology that studies how people change mentally, physically, and socially throughout the lifespan • For every age and stage of life, developmental psychologists investigate the influence of multiple factors on development, • including biological, environmental, social, cultural, and behavioral factors • Along with studying common patterns of growth and change, developmental psychologists look at ways in which people differ in their development • Developmental psychologists often conceptualize the lifespan in terms of basic stages of development

Introduction: Your Life Story • Traditionally, the stages of the lifespan are defined by age, which implies relatively sudden, age-related changes as we move from one stage to the next • Some aspects of development, such as prenatal development and language development, are closely tied to critical periods • Most of our physical, mental, and social changes, however, occur gradually, • And the theme of gradually unfolding changes throughout the ages and stages of life will become more evident as we trace the typical course of human development in this chapter • Another important theme is the interaction between heredity and environment, • Traditionally called the nature-nurture issue

Genetic Contributions to Your Life Story • A chromosome is a long, threadlike structure composed of twisted parallel strands of deoxyribonucleic acid (DNA), • which is the chemical basis of all heredity • DNA contains the chemical genetic code that directs the growth and development of many of your unique characteristics • Each gene is a unit of DNA instructions pertaining to some characteristic, • such as eye or hair color, or handedness

Genetic Contributions to Your Life Story • At conception, the genes carried on the 23 chromosomes contributed by your biological mother’s ovum were paired with • The genes carried on the 23 chromosomes contributed by your biological father’s sperm • Multiple gene pairs are involved in directing many complex features of development

Genetic Contributions to Your Life Story • Dominant and Recessive Characteristics • Genotype – the underlying genetic makeup of a particular individual • Phenotype – the actual displayed traits • When a genotype combines conflicting genetic information: • the dominant gene will influence the trait actually displayed • Traits like freckles, dark eyes, dark hair, and dimples are referred to as dominant characteristics • Because they require only one member of a gene pair to be dominant for the trait to be displayed

Genetic Contributions to Your Life Story • A recessive gene is a gene whose instructions are not expressed if combined with a dominant gene • Only expressed if paired with another recessive gene • Recessive characteristics – traits whose expression requires two identical recessive genes • Like straight hair, attached earlobes, and flat feet • We inherit from our biological parents a genetic potential: • the expression of which can be influenced by environmental conditions

Genetic Contributions to Your Life Story • The sex chromosomes and sex-linked recessive characteristics • The sex chromosomes (the 23rd pair of chromosomes) determine biological sex • The large X chromosome carries more genes than does the smaller Y chromosome, including genes for traits unrelated to sex • In females, the 23rd pair of chromosomes is made up of two large X chromosomes • In males, a large X chromosome and a smaller Y chromosome make up the 23rd pair of chromosomes

Genetic Contributions to Your Life Story • The sex chromosomes and sex-linked recessive characteristics • For males, the smaller Y chromosome often does not contain a corresponding gene segment to match the one on the X chromosome. • This means that a male can display certain recessive characteristics as the result of having only one recessive gene carried on the X chromosome • Like red-green color blindness and hemophilia • Sex-linked recessive characteristics – traits determined by recessive genes on the X chromosomes

Prenatal Development • At conception, chromosomes from the biological mother and father combine to form a single cell – the fertilized egg (zygote) • Prenatal stage – made up of three distinct phases: • Germinal (first two weeks), • Embryonic (weeks 3-8), and • Fetal (week 9-birth) periods

Prenatal Development • Germinal (zygotic) period – represents the first two weeks of prenatal development • The zygote undergoes rapid cell division before becoming implanted on the mother’s uterine wall • By the end of the two-week germinal period, the single-celled zygote has developed into a cluster of cells called the embryo

The Zygote First Division Second Division

Prenatal Development • The embryonic period – from weeks 3 to 8 • During this time of rapid growth and intensive cell differentiation, the organs and major systems of the body form. • Genes on the sex chromosomes and hormonal influences trigger the initial development of the sex organs • Protectively housed in the fluid-filled amniotic sac, the embryo’s lifeline is the umbilical cord • Via the umbilical cord, the embryo receives nutrients, oxygen, and water and gets rid of carbon monoxide and other wastes • The umbilical cord attaches the embryo to the placenta, a disk-shaped tissue on the mother’s uterine wall • The placenta prevents the mother’s blood from mingling with that of the developing embryo, • acting as a filter to prevent some, but not all, harmful substances that might be present in the mother’s blood from reaching the embryo

Prenatal Development • The embryonic period – from weeks 3 to 8 • Teratogens – harmful agents or substances that can cause malformations or defects in an embryo or a fetus; • Known teratogens include: • Exposure to radiation • Toxic industrial chemicals, such as mercury and PCBs • Diseases, such as rubella, syphilis, genital herpes, and AIDS • Drugs taken by the mother, such as alcohol, cocaine, and heroin

The Embryo 1 month old Embryo

Teratogens • Cocaine and Heroin: Miscarriage, prematurity, birth defects • Alcohol: Fetal alcohol syndrome, motor development problems • Smoking: Reduces oxygen flow, increases CO2, increases odds of prematurity, low birthweight, and miscarriage

Prenatal Development • The third month is the beginning of the fetal period, the final and longest stage of prenatal development • By the end of the third month, the fetus can move its arms, legs, mouth, and head • During the fourth month, the mother experiences quickening – she can feel the fetus moving • By the fifth month, the fetus has distinct sleep-wake cycles and periods of activity • During the sixth month, the fetus’s brain activity becomes similar to that of a newborn baby • During the final two months, the fetus will double in weight, gaining an additional three to four pounds

Fetal Development 3 month old male Fetus

Development During Infancy and Childhood • Initially, the newborn’s behavior is mostly limited to reflexes that enhance his chances for survival. • Some major newborn reflexes: • The rooting reflex – the infant turns toward the source of the touch and opens the mouth • The sucking reflex – just touching the newborn’s lips evokes this reflex • The grasping reflex – the baby will grip your fingers so tightly that he or she can be lifted upright • In addition, the newborn’s senses – vision, hearing, smell, and touch – are keenly attuned to people, • helping the infant quickly learn to differentiate between the mother and other humans

Development During Infancy and Childhood • Vision is the least developed sense at birth • Optimal viewing distance for the newborn is about 6-12 inches • The perfect distance for a nursing baby to easily focus on his mother’s face and make eye contact • Newborns respond with increased alertness to the sound of human voices

Development During Infancy and Childhood • Physical development • At birth, the newborn’s brain is 25% of its adult weight • Body weight is only 5% of its adult weight • Newborns enter the world with an estimated 100 billion neurons • After birth, the brain continues to develop rapidly • The number of dendrites increases dramatically during the first two years of life • The axons of many neurons acquire myelin: • the white, fatty covering that increases a neuron’s communication speed

Development During Infancy and Childhood • Physical development • The basic sequence of motor skill development during infancy is universal, but average ages can be a little deceptive • Each infant has his or her own: • genetically programmed timetable of physical maturation and • developmental readiness to master different motor skills • Like rolling over, sitting up, and standing

Development During Infancy and Childhood • Social and personality development • Forming close social and emotional relationships with caregivers is essential to the infant’s physical and psychological well-being • Temperamental qualities: Babies are different • Inborn predispositions to consistently behave and react in a certain way define temperament • Most researchers agree that temperament has a genetic and biological basis: • although environment can modify a child’s basic temperament • In the 1950’s Chess & Thomas rated young infants on a variety of characteristics: • such as activity level, mood, regularity, and attention span

Development During Infancy and Childhood • About 2/3 of the babies could be classified into one of three broad temperamental patterns: easy, difficult, and slow-to-warm-up • Easy babies – readily adapt to new experiences, generally display positive moods and emotions, and have regular sleeping and eating patterns • Difficult babies – tend to be intensely emotional, are irritable and fussy, cry a lot, and tend to have irregular sleeping and eating patterns • Slow-to-warm-up babies – have a low activity level, withdraw from new situations and people, and adapt to new experiences very gradually • About 1/3 of the infants were characterized as average babies because they did not fit neatly into one of these three categories

Temperament Characteristic ways of responding to the environment that vary from infant to infant (Data from Thomas, et al., 1970)

Development During Infancy and Childhood • Attachment: forming emotional bonds • Attachment – the emotional bond that forms between infant and caregivers, especially the mother • According to attachment theory, an infant’s ability to thrive physically and psychologically depends in part on the quality of attachment • In all cultures, the emotional bond between between infants and caregivers is an important relationship: • although there are cultural differences in how the attachment relationship is conceptualized and encouraged • Infants can form multiple attachments

Development During Infancy and Childhood • Depending on the parents, infants can form secure or insecure attachments • Secure attachment – occurs when parents are consistently warm, responsive, and sensitive to their infant’s needs • Insecure attachment – may develop when an infant’s parents are neglectful, inconsistent, or insensitive to the infant’s moods or behaviors • VIDEO – Attachment • The Human Experience, segment 21

Development During Infancy and Childhood • The most commonly used procedure to measure attachment, called the “Strange Situation”, was developed by Ainsworth • And is typically used with infants between 1-2 years old • The mother stays with the child for a few moments, • She then departs, leaving the child with the stranger • After a few minutes, mother returns, spends a few minutes in the room, • She then leaves, and returns again • Psychologists assess attachment by observing the infant’s behavior toward the mother during the Strange Situation procedure

Development During Infancy and Childhood • The securely attached infant will use the mother as a “secure” base from which to explore the new environment, periodically returning to her side; • Will show distress when mother leaves and will greet her warmly when she returns. • The mothers easily soothe securely attached babies • An insecurely attached infant is less likely to explore the environment, even when the mother is present and may appear either very anxious or completely indifferent • Such infants tend to ignore or avoid their mothers when they are present • Some become extremely distressed when the mother leaves the room and, when reunited, • they are hard to soothe and: • may resist their mothers’ attempt to comfort them

Development During Infancy and Childhood • Language development • By the time children reach three years of age, they have learned: • approximately 3,000 words and: • the complex rules of their language • According to linguist Noam Chomsky, every child is born with a biological predisposition to learn language – any language • That is, they possess what he calls a “universal grammar”: • a basic understanding of the common principles of language organization

Development During Infancy and Childhood • At birth, infants can distinguish among the speech sounds of all the world’s languages • By 10 months, they distinguish only the speech sounds that are present in the language to which they have been exposed

Development During Infancy and Childhood • Motherese: encouraging language development • People in every culture use a style of speech called motherese, or infant directed speech, with babies • Motherese is characterized by: • Distinct pronunciation, • A simplified vocabulary, • Short sentences, • A high pitch, and • Exaggerated intonation and expression

Development During Infancy and Childhood • The cooing and babbling stage of language development • In virtually every culture, infants follow the same sequence of language development, and at roughly similar ages • Around 3 months – infant begins to “coo” • Around 5 months – infant begins to “babble” • Infants all over the world use the same sounds when they babble, • including sounds that do not occur in the language of their parents and other caregivers • Around 9 months – infant begins to babble more in the sounds specific to their language • Babbling seems to be a biologically programmed stage of language development

Development During Infancy and Childhood • The one-word stage of language development • Long before babies become accomplished talkers, they understand much of what is said to them. • Thus, they have a comprehension vocabulary (words they understand) that is much larger than: • their production vocabulary (the words they can say) • Around their first birthday, infants produce their first real words • Usually referring to concrete objects or people that are important to the child • Such as mama, dada, or ba-ba (bottle) • During the one-word stage, babies use a single word and vocal intonation to stand for an entire sentence • “ba-ba = “I want my bottle”

Development During Infancy and Childhood • The two word stage of language development • Around their second birthday, infants begin putting words together to construct a simple “sentence” • Such as “Mama go,” & “Where kitty,” • These utterances include only the most essential words, • but basically follow a grammatically correct sequence • Children move beyond the two-word stage at around 2½ years of age • Language production and comprehension increase dramatically thereafter

Development During Infancy and Childhood • Gender-role development • Gender – refers to the cultural and social meanings that are associated with maleness or femaleness • Gender roles – behaviors, attitudes, and personality traits that a given culture designates as either masculine or feminine • Gender identity – a person’s psychological sense of being male or female

Development During Infancy and Childhood • Between the ages of 2 and 3, children can identify themselves and other children as boys or girls, • although the details are still a bit fuzzy for them • From about 18 months to the age of 2 years, sex differences in behavior begin to emerge • Toddler girls play more with soft toys and dolls, • and ask for help from adults more than toddler boys do • Toddler boys play more with blocks and transportation toys (trucks and wagons), • and play more roughly

Development During Infancy and Childhood • Explaining gender roles: Two contemporary theories • Social learning theory – gender roles are learned through reinforcement, punishment, and modeling • Gender schema theory – children actively develop mental categories/schemas (mental representations) for masculinity and femininity • Gender schemas: • Influence how people pay attention to, perceive, interpret, and remember gender-relevant behavior • Seem to lead children to perceive members of their own sex more favorably than members of the opposite sex • Help children to readily assimilate new information

Piaget’s Stages • According to Piaget, children progress through four distinct cognitive stage • Sensorimotor (0-2 years) • Preoperations (2-7 years) • Concrete Operations (7-12 years) • Formal Operations (12 and up) • As a child progresses to a new stage, his/her thinking is qualitatively different

Piaget’s Stages Sensorimotor • Understand the world through senses and motor actions • Develop object permanence – the idea that an object still exists even if it can’t be seen • CD ROM: Obj. Perm. (#15)

Piaget’s Stages Preoperative (“before logic”) • Symbolic thought – ability to use words, images, and symbols to represent the world • Thinking is egocentric (the inability to take another person’s perspective)

Piaget’s Stages Concrete Operations • Can do logical operations • Understand reversibility • Can do conservation – two equal quantities remain equal even if the appearance of one has changed

Piaget’s Stages Formal Operations: • Can do abstract & hypothetical reasoning

Development During Infancy and Childhood • CD ROM: Piaget’s Conservation Task (#18) • Studying Piaget’s theory • Generally, scientific research has supported Piaget’s most fundamental idea: • That infants, young children, and older children use distinct cognitive abilities to construct their understanding of the world • Other aspects of Piaget’s theory have been criticized

Development During Infancy and Childhood • Three criticisms of Piaget’s theory • Inaccurate assessment of object permanence • Piaget’s stages are not as universal as he believed • Underestimation of the impact of the social and cultural environment on cognitive development

Development During Infancy and Childhood • Criticisms of Piaget’s theory • Today, many researchers believe that in assessing object permanence during infancy, Piaget confused: • motor skill limitations with: • cognitive limitations • Bailargeon – used visual tasks, rather than manual tasks to challenge Piaget’s belief regarding the age at which infants acquire object permanence • 3 ½ month-old infants looked longer at a carrot that cannot be seen through a window • Showing object permanence much earlier than Piaget thought

Development During Infancy and Childhood • Criticisms of Piaget’s theory • Piaget’s stages are not as universal as he believed • Researchers have found that many adults display abstract-hypothetical thinking only in limited areas of knowledge, • And some adults never display formal operational thought processes • Some developmental psychologists emphasize the information-processing model of cognitive development • Focuses on the development of fundamental mental processes like attention, memory, and problem solving • Cognitive development is viewed as continuously changing over the lifespan

Development During Infancy and Childhood • Criticisms of Piaget’s theory • Piaget underestimated the impact of the social and cultural environment on cognitive development • Russian psychologist Vygotsky believed that cognitive development is strongly influenced by social and cultural factors • Such as the support and guidance that children receive from parents, other adults, and older children • Cross-cultural studies show that cognitive development is strongly influenced by: • the skills that are valued and encouraged in a particular environment

Vygotsky’s View • Cognitive ability falls in the "Zone of Proximal Development" Zone of Proximal Development Kid’s performance without help Kid’s performance with help

Adolescence • A transitional stage between late childhood and the beginning of adulthood, during which: • sexual maturity is reached • identity is explored • Physical and sexual development • Puberty – tends to follow a predictable sequence for each sex • Internally, puberty involves the development of the primary sex characteristics • The sexual organs that are directly involved in reproduction, such as the female’s uterus and the male’s testes • Externally, puberty involves the development of the secondary sex characteristics • Characteristics not directly involved in reproduction, but still signal sexual maturity • Such as changes in height, weight, and body shape, appearance of body hair, voice changes, and in girls, breast development

Lifespan Development