Odokuma, E.I., Eghworo, O., Avwioro, G.O., & Agbedia, U. (2008). Tongue Rolling and Tongue Folding Traits in an African Population Rasgos de Lengua Enrollada y Lengua Doblada en una Población Africana.

Source: National Human Genome Research Institute

Module 4

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for offline viewing. Please note that some animations or images may not

work.

Module 4: The Level of Intimate Social Interactions: Development

Tuesday, July 25 – Monday, July 31

Required

Reading/Viewing:

Principles of Psychology, Chapters 8–9

(Pages 322–361; 364–372; 386-397)

Module 4 online content

View the two different Ted Talks:

TED 2018. (2018, September). Implicit Bias,

Stereotype Threat and Higher Education

[Video]. TED.

TED (2008, December 17). Why We Make Bad

Decisions [Video]. YouTube.

Discussions: Module 4 Discussion

Initial responses due Friday, July 28, 9:00 AM

ET

Two peer response due Sunday, July 31, 9:00

AM ET

Leader response due Wednesday, August 2,

9:00 AM ET

Assignments: Film Response worksheet 3 (based on the two TED

Talks) due Monday, July 31, 5:00 PM ET

Live Classrooms: Tuesday, July 25, 7:30–9:00 PM ET

Activity: Complete Module 4 Review and Reflect, due

Tuesday, August 1, 11:59 PM ET

Welcome to Module 4

cas_ps101_19_su2_mtompson_mod4 video cannot be displayed

here

QUESTION 1 OF 2

Based on the video, determine if this statement is true or false.

1. In the early part of the last century parents were often told not to hold or physically comfort their infants.

TRUE FALSE

CHECK ANSWER

VIDEO FOLLOW-UP

Learning Objectives

1. List two major themes/debates in developmental psychology and give an example of each.

2. Describe stages in prenatal development.

3. Describe Piaget’s theory of cognitive development.

4. Describe and give examples of Kohlberg’s Theory of moral development.

5. Describe how “attachment” between infants and caregivers is measured and why it is important.

6. List milestones in language development and how the environment supports language development.

7. Compare cross-sectional and longitudinal research designs and give examples.

Developmental Psychology

This branch of psychology is focued on how people change physically, mentally, and socially over the course of their life span. At each period of the

lifespan, developmental psychologists study numerous factors at all of the levels that I introduced the first day of class, including biological,

psychological, small intimate interactions, the larger social context, and culture.

Major Themes in Developmental Psychology

A number of major themes recur in the study of developmental psychology, and I outline these below.

Basic Developmental Stages

The first important theme is the idea that individuals go through basic developmental stages. I’m going to introduce several stage theories.

According to stage theories, individuals go through various periods of development referred to as stages. At each stage, development is not

only quantitatively different (that is to say, there is more of something, like vocabulary increases in language development) but

also qualitatively different (that is to say, one goes about things in a completely different way—not just “more” but also “different”). At each stage,

the individual is very different in kind. The idea of stages has a number of implications:

Implications of Stages

Stages are roughly defined by age, although a certain amount of variability exists between individuals. There are also sudden stage-related

changes. We will talk about this when we talk about cognitive development and language development. Although there is definitely evidence for

stages of development, much of our physical, mental, and social development occurs gradually, unfolding over time.

There also may be critical periods in development. Critical periods are times in which a certain developmental event or task must take place. If it

doesn’t happen at that critical period, it will never happen normally. There are also sensitive periods where it is best to accomplish this

developmental task, but it is still possible at other times. A good example of this is with second language learning. A second language is most easily

learned during childhood, although, with a lot of work, it can be learned later. Childhood is a sensitive period for the learning of a new language.

Nature versus Nurture

The second important theme is nature versus nurture. This is an old debate about how much of a person’s personality, capabilities, and other

characteristics are determined by nature (genetics, what we bring into the world when we are born) and nurture (the way in which the environment

supports or doesn’t support our development). Now the truth is, both are obviously very important. What we are most often interested in

understanding is the interaction between nature and nurture.

So let’s begin looking at development from the time of conception, through the prenatal period and into infancy. How does the young child become who

he or she is?

Genetic Contributions

In recent years our understanding of genetic contributions to all sorts of behavioral characteristics has exploded. Research has examined genetic

contributions to intelligence, emotional stability, mental health disorders, personality, etc. Behavioral genetics, combines genetics and psychology and

helps us to understand the kinds of behavioral characteristics that are transmitted genetically from parent to child.

So let’s go through some of the basics. Many of you, probably most of you, have taken biology.

You know that our chromosomes are long threadlike structures that look a bit like a twisting ladder and are composed of deoxyribonucleic acid or

DNA. DNA is the chemical basis of heredity and carries genetic instructions in the cells of our body.

The gene is a basic unit of heredity, and genes direct the development of particular kinds of characteristics, including some behavioral

characteristics. Now I’m not going to cover the entire biology of genetics here, but I do want to think about how it applies to behavioral

characteristics.

As you are aware, at conception your biological mother contributes 23 chromosomes, and your biological father contributes 23 chromosomes; this

new combination makes the unique you. Your new chromosomes contain approximately 24,000 genes. Although some genes have direct effects,

and I’ll talk about some examples of that in a minute, most traits are “polygenetic” or influenced by more than one gene (e.g., our height is

influenced by at least four genes). Some simple traits, such as eye color (light or dark), are determined by a single gene.

I like to define a couple of additional terms.

First, your genotype describes your underlying genetic makeup and it may include genetic instructions for traits that are never actually

displayed (the gene is turned off).

Second, your phenotype refers to the observable traits or characteristics, and it is determined by the interaction between genes and the

environment. Let me give you an example. Do you have freckles? Well freckles are caused by a gene, but this gene will only display itself

under certain circumstances. If you have the freckles gene and you are exposed to sunlight, you will develop freckles. But think about rich

white women on plantations in the South during the Antebellum era. These women really had no jobs at all (after all, they were completely

taken care of by slaves), and having extremely white creamy skin was considered the height of beauty. These women would carry parasols or

wear hats and long sleeves—all to avoid too much contact with the sun. Did some of them have the freckles gene? Who knows! On the other

hand, if you have the freckles gene today you are more likely to display it, as most of us are going around in short sleeves during the

summer and warming ourselves in the sun (ah!). There has to be an interaction between genetics (the freckles gene on the genome) and the

environment (the sunlight) for that trait to be displayed in the phenotype.

Third is the idea of a dominant gene. You get one gene (called an allele) from your biological mother and one from your biological father.

Dominant genes are those that will display themselves if even one allele is present. You only have to have one dominant gene in order for the

trait to be evident. For example, curly hair is a dominant trait. If you got the straight hair gene from your biological mother and the curly hair

gene from your biological father, you’re likely to have curly hair.

Fourth is the recessive gene. A recessive gene contains genetic instructions that will only be expressed if the individual has TWO recessive

alleles (one from each biological parent). On the next set of slides, I give you the example of tongue rolling, so let’s go through these…

Do you see the image on this slide? This is tongue rolling. Some of you can do it and some of you can’t. I really don’t

think it’s a great virtue, so if you can’t do it don’t feel bad! Apparently, the ability to roll one’s tongue is determined by

one dominant gene. Can you believe that? If you look at the table below, you can see how it works.

Along the top row is the genotype. We refer to a genotype as “homozygous” when both biological parents contribute

the same type of gene/allele (dominant or recessive). We refer to a genotype as “heterozygous” when each biological

parent contributes a different type of gene (one dominant, one recessive).

Genotype Homozygous Heterozygous Heterozygous Homozygous

Parental

Alleles

Mother:

Tongue

rolling

Father:

Tongue

rolling

Mother:

Tongue

rolling

Father:

Non-Tongue

rolling

Mother:

Non-Tongue

rolling

Father:

Tongue

rolling

Mother:

Non-Tongue

rolling

Father:

Non-Tongue

rolling

Phenotype Tongue rolling Tongue rolling Tongue rolling Non-tongue rolling

So let’s go through it; remember you only have to have one dominant gene for the trait to be expressed in your phenotype. So, in the first case you

are homozygous for the dominant tongue-rolling gene as both your parents gave you a dominant gene for this trait. So your phenotype is positive for

tongue rolling. (Isn’t this exciting?) In the next case, your mother had the dominant tongue-rolling gene, but your father gave you a recessive “non-

tongue-rolling” gene. You are still a tongue roller, but your genotype is heterozygous! In the next case your mother had the recessive non-tongue-

rolling gene, but your father gave you a dominant tongue-rolling gene. So, again, you are heterozygous, but you are a tongue roller (you have one

dominant gene). In the last case, both of your parents gave you the recessive non-tongue-rolling gene. You are homozygous for the tongue-rolling

gene and you cannot do tongue rolling. But wait! It turns out that tongue rolling is not entirely genetic! You can still learn the skill. But, why bother?

Other Examples of Recessive Traits

Susceptibility to poison ivy (oh I hope you aren’t homozygous for that one; I unfortunately am!), straight hair, and some diseases (examples include

sickle cell disease and phenylketonuria or PKU) are examples of recessive traits.

Now, your sex chromosomes are the 23rd pair of chromosomes in humans. They determine your biological sex (gender is a separate issue, as it

speaks to one’s identity and not to a biological characteristic). Instructions on these genes direct the development of your gonads in utero (among

other things). This gets us to the topic of sex-linked recessive characteristics. Females have two large X chromosomes for the 23rd pair—one from their

biological mother and one from their biological father. Males have one large X chromosome for the 23rd pair (from their biological mother) and one

smaller Y chromosome (from their biological father). There are more genes on the X chromosome than on the Y chromosome. If you think about it, the

Y chromosome, shaped like a Y, is missing a whole leg of potential genes. So any genes for recessive traits on that leg of the X chromosome 23 will be

displayed (there is no other gene to contradict them). This is why men are more likely to have these sex-linked characteristics, as they are caused by

recessive genes on chromosome 23. Examples of sex-linked traits include colorblindness, hemophilia, and male pattern baldness. For a woman to have

any of these characteristics she would have to have genes from both biological parents that were recessive for these traits (not common).

Source: National Human Genome Research Institute

cas_ps101_19_su2_sex_chromosome video cannot be displayed

here

The human genome project identified all estimated genes on our human chromosomes. Although we know where they are, we don’t know what they all

do. But let me point out a few that are particularly interesting.

Alzheimer’s disease. There are some forms of Alzheimer’s disease, particularly those with very early onset, that are genetically determined. You

can actually take a genetic test to see if you will have this early onset form of Alzheimer’s disease (although it is usually only recommended if it

runs in your family). There are other forms of Alzheimer’s disease that may be partially genetically determined (risk genes).

Amyotrophic lateral sclerosis or ALS results in progressive degeneration of motor neurons in the spinal cord, leading to paralysis. Some forms

of ALS (maybe 5 to 10%) are caused by familial transmitted genetic mutations.

Huntington’s disease is a particularly interesting example of a genetically transmitted disease. The Huntington’s gene is a dominant one and if

you have the gene you will develop the disease. The disease usually begins to show symptoms during a person’s 40s, although it can onset earlier

in some people. The story of how the Huntington’s gene was discovered is a fascinating one and I encourage you to read more about it. But we

will move along to a few other topics.

Another example of a genetically determined medical condition is Down’s

syndrome. In this syndrome individuals typically have mild intellectual disabilities,

short stature, and a distinctive appearance. Down’s syndrome is not “inherited”

but rather a defect that occurs during meiosis when egg and sperm come together

to form a new genetic being. In the case of Down’s syndrome, the process results

in what is called a trisomy on the 21st chromosome. Instead of two chromosomes

there are three (thus a trisomy).

As we learn more about the human genome and its potential impact on behavioral

health, risk of disease, and other outcomes, families face many difficult decisions. If

you could get a genetic test that would tell you 100% that you would get a terrible

disease in your 40s and there was no treatment, would you want to take the test? What

happens if your health insurer or employer finds out? Lots of difficult questions!!

Ok, so having reviewed some basic information on genetics, let’s talk about how the baby develops physically before and after birth.

Physical Development

From the time the egg and the sperm get together and continuing throughout childhood, we see huge changes in physical development in a short

period of time.

Prenatal

Let’s focus first on the prenatal stage, that is the stage of development before the baby is born. The prenatal stage is divided into three periods.

The first period of prenatal development is known as the germinal period, and it lasts for approximately two weeks. We refer to the developing

organism as a germ or zygote. Two major developments occur during this time. First, the cells of the zygote rapidly divide, expanding in size. Second,

the zygote implants in the lining of the uterus, where it will grow and develop for the next nine months.

Germinal Period

Source: Human Development

The second period of prenatal development is known as the embryonic period, and it lasts from approximately week 3 through week 8. A number

of important events begin to unfold during this period. First, cell growth accelerates and cells begin to differentiate, with those that will become heart

cells becoming different from those that will become skin cells or bone cells, etc. The organs and major systems of the body form, and genes on our

sex chromosomes (chromosome 23) trigger the initial development of the sexual organs. Second, the amniotic sac where the baby will float for the

next nine months develops, as does the umbilical cord that will transmit vital nutrients to the baby and will carry away waste. Third, the baby becomes

increasingly vulnerable to the impact of teratogens, which are harmful substances that can cause defects in the developing embryo (and later the

fetus).

Source: Carnegire Collection of Embryos

Here are some examples of teratogens:

1. Radiation. For the women in the class, you’ve probably been asked before you’ve had your dental X-rays whether or not you were pregnant. This

is because radiation is a teratogen. If you are pregnant and need to get X-rays, you probably should wait until after the baby is delivered.

2. Toxic industrial chemicals. Let’s face it, mercury, PCBs, and other toxic industrial chemicals probably aren’t good for any of us, but they are

particularly bad for the developing baby. It’s important to avoid exposure to these during pregnancy.

3. Certain diseases. Rubella, syphilis, AIDS, and many others can have a very negative impact on the development of the baby. This is one of the

reasons that it is particularly important for pregnant women to take good care of their health, get prenatal care, and avoid exposure to diseases.

We will get into other examples of this later in the semester when we talk about mental illness. The impact of any particular teratogen will depend

on many factors, including timing (when during pregnancy the exposure occurs), maternal health, maternal age, and nutrition. I want you to look

at the next slide, but don’t panic! There’s a lot of information here, but I only need for you to take away two important points.

Source: Researchgate

The first point is that different organ systems develop at different times and therefore may be most vulnerable at different times during

prenatal development. For example, the heart is developing during approximately weeks 7 to 8, and it is during this period that it is most

vulnerable to the impact of teratogens that affect cardiac development. The second point to notice is that the development of the central

nervous system occurs over a long period of time, making it vulnerable to the impact of teratogens throughout much of gestation.

4. Drugs. It is very important for a pregnant woman to talk to her doctor before taking drugs, either illicit drugs, over-the-counter drugs, or

prescription drugs. Interestingly one of the drugs that has a particularly negative impact on the developing baby is alcohol. Many people would

speculate that heroin or cocaine would be far worse (after all, they are illegal!), but alcohol is very bad. Numerous studies suggest that alcohol

exposure is one of the main causes of birth defects in children. Nowadays pregnant women are cautioned against using any alcohol (having any

alcoholic beverages at all) during pregnancy. As a person who very much enjoys wine, I would still suggest that any woman put that bottle away

in a safe place and enjoy it after the baby is born. Additionally, if a woman is breast-feeding, it’s best to avoid alcohol (and other drugs) for that

time as well, as those substances can enter breast milk and impact the infant.

The third period of prenatal development is known as the fetal period. At this point we refer to the developing child as a fetus. The fetal period

extends from week 8 until the baby is born at approximately 40 weeks. The fetus is rapidly developing and gaining in size and ability. By the end of

the 3rd month, the fetus can move its arms, legs, mouth, and head. It’s interesting to me that when my mother was pregnant (in the 1960s), doctors,

pregnant women, and their partners had little idea about what the baby might be like until he or she arrived. Now, using sonograms, you can get a

very good picture of how the baby is developing. It’s fascinating to look at a sonogram and realize that the baby is actually sucking her thumb in utero!

During the 4th month, mothers began to experience what is known as quickening, that is, the movements of the baby. At first the mother may begin to

think that she is having a bad tummy episode (maybe thinking that she had a dinner that was a bit too spicy), but it’s that baby moving! By the end of

the 5th month, most of the brain cells are already in place, although they will continue to develop until birth and certainly thereafter. By the end of the

6th month, the baby’s brain activity is similar to that of a newborn baby. During the final few months of development in utero the baby is putting on

weight and the lungs are continuing to develop, as the baby is preparing to live outside the uterus.

Newborn

Now that we’ve talked about prenatal development, let’s talk about what happens when the baby arrives.

The new baby comes into the world well-prepared. Now, many people when they see a newborn may think that baby is a fairly incompetent individual,

but I’m telling you that that is not the case! I would argue that that baby is ready to do what is needed to thrive. This newborn is competent! So what

does the newborn need to do to survive? Two main things: gain weight and connect with the supportive social world around her. The newborn comes

into the world with the skills that allow her to do this. What are these skills?

Reflexes. The baby has a number of reflexes that contribute to her survival. First, they have the rooting reflex. If you brush a baby’s cheek with

your finger, the baby will turn their head toward your hand and open their mouth. That newborn is ready to feed. Think of this: the mother’s breast

brushes across the infant’s cheek, and the infant turns their head and is ready to breastfeed. This rooting reflex is there. Second, they have

the sucking reflex. If you put your finger on the baby’s lips, they will begin to suck. Again, ready to be fed. So that baby is ready to gain weight.

Third, and interestingly, the newborn has the grasping reflex. An infant can hold her weight with her grasp. That’s pretty amazing. This grasping

reflex may be evolutionarily quite old. Think of other primates. When the chimpanzee baby is born, it needs to hold on to its mother as she swings

from tree to tree. That grasping reflex is essential to his survival, so perhaps the grasping reflex is an old one from an evolutionary standpoint, one

that we had when the baby still needed to really hold on. Of course now we have car seats, and baby carriers, and strollers, so perhaps the grasping

reflex doesn’t have quite the same value as it once might have had.

Social attunement. Interestingly, the newborn is able to differentiate between their mother and other human beings by both voice tone and scent.

The baby is prepared to make that crucial social connection. Although vision is the least developed sense at birth (indeed, the newborn is legally

blind), the baby is able to see well from about 6 to 12 inches. This is the perfect distance for the baby to make eye contact while breastfeeding or

taking a bottle! And so the relationship begins. Finally, babies are drawn to human voices; they are capable again of making those human connections

that are so important to their survival.

Infancy

The first two years of life are called infancy. During this time, there are rapid and dramatic changes on many fronts.

Physical Development in Infancy

So what’s happening early on to that newborn baby? Well, at birth the newborn’s brain is approximately 25% of its adult weight. In contrast, the baby’s

total weight is about 5% of its adult weight. The baby has a very heavy head! The baby’s brain has almost all of the neurons it will ever have. However,

the connectivity of the human brain increases radically in the first two years of life, particularly, as the number of dendrites increases and the axons

of many of the neurons acquire myelin.

Major Milestones in Motor Development

Motor Milestone Mean Age (when 50% of infants have achived milestone)

Lifts head 90 degrees while on stomach 2.2 months

Rolls over 2.8 months

Sits with support 2.9 months

Sits without support 5.5 months

Stands with support 5.8 months

Crawls with support 7.0 months

Walks with support/cruises 9.2months

Stands independently 11.5 months

Walks independently 12.1 months

Walks up steps 17.0 months

Kicks ball forward 20.80months

Monk, Catherine & Hane, Amie. (2014). Fetal and Infant Brain–Behavior Development: Milestones &

Environmental Influences. 10.1093/oxfordhb/9780199778072.013.20.

What are some of the major milestones of physical development? First, the baby can lift his or her head at about 2 months of age. Second, the baby

can begin to roll over at about two and a half months of age. Be careful not to leave that baby alone on a bed! By about 3 months the baby can sit up

if propped up by pillows. By about 6 months of age the baby can sit on his or her own. You can tell how long the baby has been sitting by how adept

they are at sitting. A very new sitter will look unstable and will fall over easily if he or she reaches for something. The experienced sitter can turn and

reach and do all sorts of activities while sitting.

By about six and a half months the child can stand holding on. Interestingly, as a child is developing these skills, he may become distracted from

other developmental tasks. For example, the child who was sleeping through the night may stop doing so when he begins to walk or engage in other

physical activities. He may not eat as readily. It’s hard to do all those other things when your focus is on walking! I remember when my son was first

able to pull up and stand in his crib. He would spend so much time standing up, but then would start to cry because he couldn’t get down! We would

then go in and help him down, and he would of course pull himself back up&#x2014