Developmental Psychology The study of how people grow, mature and change over the life span.

Developmental Psychology

The study of how people grow, mature and change over the life span.

Developmental Psychology

• Stages of development– Fetus: conception to birth– Infant: birth to 1 year– Toddler: 1 year to 3 years– Early childhood: 3 years to 6 years– Childhood: 6 years to puberty (11-15)– Adolescence: puberty to independence (18-22)– Young adulthood: 20-40– Middle adulthood: 40-60– Late adulthood: 60-75

Developmental Psychology

• Dimensions of developmental psychology– Biological: brain, motor, sensory, etc.

– Cognitive: thought, language, memory, etc.

– Social-emotional

– Moral

Milestones in Motor Development

Basic Developmental Questions

• The Nature-Nurture Debate– Genetics vs. environment, and their interaction

• Critical periods (also known as sensitive periods)– Especially in vision, social development, and language

• Developmental Research Strategies– Longitudinal vs. cross-sectional research– Cohorts: groups of people born around the same time

Developmental Research: Cohort Effects

• In cross-sectional research– We don’t know whether the differences between the

cohorts are due to their ages, per se, or are due to the fact that they were born at different times and had different experiences as a result.

• In longitudinal research– We don’t know whether the changes that occur in our

cohort are due to their changes in age, per se, or are due to the particular year in which they were born.

• Sequential studies– A combination of longitudinal and cross-sectional

• Different cohorts studied longitudinally

Conception & prenatal development

• Genetic Building Blocks

• Prenatal or “fetal” stages– Zygote: fertilized egg– Germinal: until 2 weeks– Embryonic: until 8 weeks (1” and 1/10 oz)

• Forebrain, midbrain, hindbrain begin to form by week 4

• Cells forming the cortex are visible by week 7

– Fetal: until birth at 40 weeks (M = 7 lbs.)• By the 7th month the fetus has a working nervous system

• At birth the brain has cortical layers, neuronal connectivity, and some myelination

• Hormonal influences in the womb are substantial

Teratogens and the Fetus• Alcohol

– A mother’s heavy drinking can lead to fetal alcohol syndrome– One drink per day can cause motor and balance deficits in the child– The most damage is done during the 3rd and 4th weeks, a time when

many women don’t yet know that they are pregnant– Detrimental effects are still observed when the child is 14 years old

• Cigarettes• Cocaine• Aspirin• Marijuana• AIDS• Rubella (German measles)• X-rays• Mercury (fish)

Newborn infants (neonates)• Taste

– Newborns prefer sweet tastes

• Smell (olfaction)– Newborns prefer the smell of their mothers’ milk

• Hearing (Audition)– Newborns are startled by and orient toward loud sounds

• Vision– Visual acuity in newborns is 8-12 inches

• Newborns can see their world clearly, but only when object is within 8” (20-600 vision at birth)

– Infant can see an object at 20 feet about as well as an adult can see an object at 600 feet

– Adult levels of acuity reached at one year

• Reflexes

The Developing Brain

• At birth, all 100-200 billion neurons are in place, but few connections exist

• During first year, axons grow, dendrites multiply, and connections form

• Over next few years, active connections strengthen and inactive connections atrophy (synaptic pruning)

• Myelination until 4–7 years in many areas of brain and until 20 years old in the frontal lobes

At Birth During First Year Next Few Years

The highest levels of density can be thought of as the times when the brain is most plastic — most able to change.

Neonate Social Development: Attachment

• Attachment: A deep emotional bond that persists over time and across circumstances that an infant develops with its primary caretaker. Includes …– A desire to be physically close

– A sense of security when physically close

– Feelings of distress when not close

Separation Anxiety

• Separation anxiety is a fear reaction when the primary caregiver is absent

• Seen in all cultures

• Corresponds with development of object permanence

Harlow, Bowlby, and Ainsworth

• Harlow (1958, 1971): infant rhesus monkeys preferred terrycloth substitutes over wire substitutes with a bottle of milk

• Bowlby (1969, 1983): theory of attachment arguing that clinging and crying enhance the infant’s chances for survival

• Ainsworth (1973, 1991): measured and classified the quality of attachment

Styles of Attachment

• Strange Situation Test: A parent-infant “separation and reunion” procedure that is staged in a laboratory to test the security of a child’s (1-2 yrs. old) attachment

• Secure Attachment: Baby is secure when the parent is present, distressed by separation, and delighted by reunion; about 60% of infants

• Insecure Attachment– Anxious-ambivalent (resistant): baby clings to the parent when

present, cries at separation, and reacts with anger or apathy to reunion

– Avoidant: indifferent or avoidant during presence, separation, and reunion

Other issues in attachment• Biology

– The hormone oxytocin plays a role in attachment.

• Why do infants differ in attachment style?– Temperament– Caregiver responsiveness– Caregiver-infant fit

• Early attachment styles are predictive of social behavior in elementary school (and adults?).– But predictability is not 100%– Internal working models

• Based on their first intimate relationship (their attachment relation with the primary caretaker), children develop an idea of what intimate relationships are like and they carry this idea into all of their new relationships. This idea is sometimes termed an internal working model.

• Daycare

Infancy and Childhood I• Experimental techniques for assessing a baby’s

knowledge– Preferential looking technique

• Babies look longer at novel or interesting stimuli– When shown two stimuli simultaneously, if a baby looks longer at one,

then the baby can tell the difference between them

– Using this technique, it has been found that . . .• 2- to 5-day old infants prefer high-contrast patterns and faces• 12- to 21-day old infants imitate adult facial expressions• By 2 mos., infant can discriminate colors and focus on objects

as well as an adult (if the stimuli are displayed close enough)• By 6 mos. 20/100• By 11 mos., adult level visual acuity• Depth perception emerges between 3 and 6 ½ months

Infancy and Childhood II• Experimental techniques for assessing a baby’s knowledge

– Habituation paradigms• An infant will become habituated to (become bored with) a stimulus that

does not change • However, if the infant shows a “recovery response” (i.e., dishabituates) to a

change in the stimulus, this indicates that it can distinguish between the old and new stimuli

– Using this technique, it has been found that . . .• 2-day old infants prefer their mother’s voice over an unfamiliar female

voice • 2-day old infants prefer particular stories that their mother read while the

infant was still in utero (i.e., in the womb)– When given a pacifier that the infant can use to control which stimulus is

presented– When measuring sucking rate

» The frequency and intensity with which an infant sucks a pacifier

• Infants prefer high-pitch sounds and the human voice– “Motherese”

Infancy and Childhood III• Rovee-Collier (1999) and the development of memory

– Baseline phase: measure kicking rate when ribbon is not tied from baby’s ankle to mobile

– Learning phase: measure kicking rate when ribbon is attached to the mobile and the mobile moves when baby kicks

– Test phase: after some period of time, reattach ribbon and measure kicking rate

• Using this technique, it has been found that . . .– 6 week olds will kick to move the mobile attached to their foot one

week after the learning phase (Rovee-Collier, 1988)– 3 month olds that learn to kick when the mobile blocks have A’s

on them will not kick as vigorously with a mobile that has 2’s on it– Memories in 3 month olds can even be reactivated a month later

with a simple reminder (the experimenter moves the mobile once)– Infants remember longer as they get older

• By 18 mos., they can remember the learning phase for several weeks

Infancy and Childhood IV

• Memory problems in childhood– Infantile amnesia (also known as childhood amnesia)

• Most people cannot recall anything that happened before the age of 3

– Source amnesia• Children have special difficulty remembering where they learned

something.

– Confabulation• Children make things up when asked about something.

– Children’s memory, especially preschoolers, is highly vulnerable to repetition, misinformation, leading questions, and outside sources of information

• Children are notoriously unreliable eyewitnesses

– Children have relatively poor metamemory skills• Metamemory refers to a person’s knowledge about the contents, and

regulation, of memory.

Piaget’s Theory of Cognitive Development

• When testing children, Piaget observed that children at different ages make characteristic errors – These errors signal the fact that children at different ages

use a logic that is different from that of adults

• Children form schemas and use these schemas to make sense of new information – Assimilation: Children incorporate new information into

their existing schemas– Accommodation: Children alter their existing schemas in

order to make sense of new information

General elements of Piaget’s Cognitive Stage Theory

• Children pass through a series of four cognitive stages– The exact age at which children transition from one stage

to the next varies from child to child– The sequence of stages is universal– The transition from one stage to the next is relatively

abrupt – The transition from one stage to the next consists of

qualitative (not quantitative) changes in the way the child comes to understand and explores their world

Four stages of Piaget’s Theory of Cognitive Development

• Sensorimotor (0-2)• Preoperational (2-6)• Concrete Operational (7-11)• Formal Operational (13-Adult)

• Operations – the ability to internally manipulate ideas according to a stable set of rules

Sensorimotor stage

• 0-2 years old• Infants come to know their world through physically

interacting with their environment– From 1-5 months, the primary tool of exploration is the

mouth

• Infants younger than 8 months old lack object permanence– That is, when an object is out of sight, it is out of mind– One of the reasons infants like to play peek-a-boo – It is now known that infants as young as 4 months old

will demonstrate object permanence when tested using more sensitive tasks

Representational Thought

• Representational thought – The ability to create and use mental representations

(internal images of absent objects and past events) and symbols (words and images that do not have an iconic relationship with their referent)

• The development of representational thought bridges the sensorimotor and preoperational stages

• Some examples– Solve sensorimotor problems without trial and error– Deferred imitation

• The ability to remember and copy the behavior of models that are not immediately present

– Make-believe (pretend) play

Preoperational Stage• 2-6 years old• During second year, memory improves

• Children move from playing peek-a-boo to playing hide-and-seek

• However, they lack full use of operations – the ability to internally manipulate ideas according to a stable set of rules

• Egocentrism– Others can tell what they are thinking

– Others know everything that is going on in their lives

– Hiding in full view

• Lack of conservation– Conservation: Basic properties of an object or situation are

conserved (remain stable) despite superficial changes

Egocentrism: The 3 mountain task

• Let the preoperational child walk around the display for themselves.

• Then ask them to pick the picture of the mountains that the bear sees.

• They just pick the picture that they themselves see.

• They cannot take the bear’s perspective.

Operational Stages• Concrete Operational (7-11 years old)

– Less egocentric– Understands conservation– Understands transitivity (If A>B and B>C, A>C)– But cannot state general abstract rules that govern a

variety of similar situations • 2 is even, 2+1 is odd, as are 4+1, 6+1, 8+1, but the child cannot

state the principle “Any even number plus 1 is an odd number”

– Tends to use trial and error approaches for problem solving

• Formal Operational (age 13 –adult)– Now has the cognitive capacity for thinking logically, but

it is not necessarily the case that every adult does so

The pendulum problem• The pendulum problem clearly differentiates the concrete

operational and the formal operational stages.– The pendulum problem: give a child strings of different lengths,

objects of different weights, and a bar to hang the string from. Ask them to figure out what influences the speed with which the pendulum swings through it’s arc

– Concrete operational children experiment unsystematically. For example, they don’t hold all other things constant while varying one thing.

– Formal operational children solve the problem in a hypothetico-deductive fashion (begin with a theory, deduce particular hypotheses, test these hypotheses systematically)

• The theory is that the length of the string, the weight of the object, the height to which the object is raised, and the force with which it is pushed all contribute to the speed. Then they test this systematically.

Challenges to Piaget: Earlier and More• Violation of expectation paradigms

– Habituate the infant to a possible event, then compare with looking time to an “impossible” event

– If the baby looks longer at the impossible event, this shows that the baby expected a certain event to occur and was surprised when it did not

– Using this technique, it has been found that . . .• 4.5 month old infants have object permanence• 4-month old infants expect that two similar objects moving together are part

of a single object• 3-month old infants know that objects do not hang suspended in mid-air

without support• 5-month old infants have rudimentary arithmetic skills

– Looked longer (were surprised) when they “expected” a certain number of objects to be behind a screen that was removed, but there was a different number of objects instead

Understanding the relation between movement and physical properties requires cognitive skills. Infants appear to use movement to infer that objects moving together are continuous.

Infants seem to intuitively sense that a box placed in midair must fall.

Children who might not have succeeded on Piaget’s marble test were able to choose the row that contained more items when those items were M&Ms and the test question was Which row would you like to eat?

Theory of Mind

• Theory of mind– Knowing that other people have mental states and using

that knowledge to explain and predict their behavior• Children begin to read other people’s intentions by the end of

their first year and become very good at doing so by the end of their second year

• Children can take another person’s perspective by the end of their fourth or fifth year

– The false belief test

– Good cross-cultural evidence

– Not a problem with general intelligence, as kids with Down syndrome can do the false belief test

Moral Reasoning

The Heinz dilemma

• In Europe a woman was near death from cancer. There was one drug that the doctors thought might save her. A druggist in the same town had discovered it, but he was charging ten times what the drug cost him to make. The sick woman’s husband, Heinz, went to everyone he knew to borrow the money, but he could only get together half of what it cost. The druggist refused to sell it cheaper or let Heinz pay later. So Heinz got desperate and broke into the man’s store to steal the drug for his wife. Should Heinz have done that? Why?

Kohlberg’s Stages of Moral Reasoning

• There are three stages in Kohlberg’s theory– Preconventional

– Conventional

– Postconventional

• The difference between these stages is not necessarily determined by what decision a person makes– In other words, saying Heinz should not steal the drug is not

automatically a sign of a higher stage of moral reasoning

• Instead, the difference between these stages is determined by the reasoning behind the decision

• The following slides should make this clear

Preconventional Level• At this level of moral reasoning, the reasons behind the

decision emphasize avoidance of punishment and obtaining reward

• If a person said that Heinz should not steal the drug because– Society will punish him for the crime (avoidance of punishment)– It’s more risk to Heinz than it is worth, since if he is caught, he

will go to jail, his wife will die, and he won’t be there for her (emphasis on the fact that Heinz will lose the reward of being with his wife)

• If a person said that Heinz should steal the drug because– His wife’s family would be less critical (avoiding punishment)– He would still have his wife after spending some time in jail

(emphasis on the reward of having his wife)

• All of these people would be described as being at the preconventional level

Conventional Level• At this level of moral reasoning, the reasons behind the

decision emphasize meeting learned moral standards, avoiding disapproval, and maintaining law, order, honor, and duty

• If a person said that Heinz should not steal the drug because– What will others in society think of me? (Avoiding disapproval) – Laws state stealing is illegal and everyone must follow the rules,

regardless of how they feel (Maintaining law and order)

• If a person said that Heinz should steal the drug because– His wife’s family will think more highly of him (seeking approval) – It is honorable to sacrifice oneself (and avoid the guilt of dishonor)– It is one’s duty (by virtue of one’s marriage vows)

• All of these people would be described as being at the conventional level

Postconventional Level: Part I• At this level of moral reasoning, individuals

– Understand the notion of social contract• Laws and rules are flexible instruments for furthering human

purposes

• When a law is consistent with individual rights and the interests of the majority, everyone agrees to participate because it is the most good for the most people

• Alternative social orders are possible

• There should be fair procedures for interpreting and changing the law

– Follow there own conscience, which is based on carefully reasoned-out principles, such as

• Equal consideration of the claims of all people

• Respect for the dignity of each person

Postconventional Level: Part II• If a person said that Heinz should steal the drug

because– The law against stealing is wrong, when the stealing is

from a person that is charging exorbitant prices and people are dying because of it (an individual’s right to life is violated)

– What value can be held more highly than the value of life? It doesn’t make sense to put respect for property above respect for life.

• Both of these people would be described as being at the postconventional level.

Criticisms/Alternatives to Kohlberg

• Some cultural differences not reflected in this theory• Although moral reasoning and moral behavior are

often related, moral reasoning is not a necessary component for moral behavior

• Instead, morality in children is rooted in moral emotions– Empathy, sympathy, guilt, shame, and embarrassment– How children select between fulfilling one’s own desires

and meeting the needs of another person is predictive of moral behavior

– Parents’ behaviors influence the development of moral emotions

Language Development I

• Elements of Language– Phoneme: Basic, distinct sounds of a spoken language.

• Over 40 phonemes in English

– Morpheme: The smallest meaningful unit of a language– Syntax: Rules of grammar that govern how words can

be combined into sentences in order to convey meaning.• In English we use word order

– Bill told the men to deliver the piano on Monday.– Bill told the men on Monday to deliver the piano.

– Beth asked the man about this headaches.– About the Beth headaches man asked his.

Lanuage Development II

• Characteristics of Human Language– Semanticity

• The property of language that describes the separate units and how these units have meaning.

– Generativity• Property of language that accounts for our capacity to use a

limited number of words to produce an infinite variety of expressions.

– Displacement• Property of language that allows communication about matters

that are not here and not now.

Generativity

Language Development III

• Newborns can differentiate linguistic stimuli on a variety of dimensions – pa vs. ba

– different multisyllabic words

• Infants as young as four days old prefer to listen to their native language

• After several months of exposure to their native language, babies lose the ability to distinguish between phonemic sounds that are not important to their native language

• All of which supports the notion that they are born with a LAD (language-acquisition device)

Language Development IV

• By age 6, children know 14,000 words and syntax– Adults know 50,000 – 60,000 words

• Developmental sequence– Newborn: crying– Second month: babbling – One year old: first word (ba for bottle)

• From 1 year old to 2 years old, child accumulates 250 words

– Two years old• naming explosion begins (learn an average of 9 words per day)• vocabulary is larger if parents talk with child• telegraphic speech (“more juice”)

– 3 to 5 years old• As children learn syntactic and grammatical rules, overgeneralization

may occur and child may make errors that they did not make earlier– Like adding –ed to run instead of saying “ran”

Other Language Development Issues I

• Vigotsky: The role of culture in language– Social and cultural context influences language

development, which in turn influences cognitive development.

• First, the child directs their speech towards others, asking for food or toys.

• Later, they begin to direct their speech inwards, giving themselves directions or talking to themselves while playing.

• Eventually, children internalize their words into inner speech: verbal thoughts that direct both behavior and cognition.

– In the end, your thoughts are a product of (are determined by) the society and culture in which you were raised.

Other Language Development Issues II• Learning to read

– Phonics approach• Traditional approach• Memorize the mapping between the letters and their sounds• Then learn the exceptions

– Whole language approach• Has become popular the last twenty years• Learn to read the way you learn to talk

– We don’t process individual phones when we hear speech, so why should we do it when we read?

• Learn individual words and learn to connect them in the context of a sentence that has meaning.

• Which approach is better?– The evidence clearly supports the phonics approach (Rayner et al.,

2001)

Can Non-Human Apes Learn Language?

• Many apes of several species have learned various different signing systems

• Is it language?– Semanticity: “Language apes” satisfy this criterion– Generativity: Bonobos can use the same words in

different orders to initiate different actions– Displacement: Researchers say apes refer to past events,

but most evidence is anecdotal

• However, non-human apes never caught on to the fact the language is fundamentally a tool used to communicate meanings, thought, and ideas