Read Psychology for Dummies Online
Authors: Adam Cash
Tags: #Psychology, #General, #Body; Mind & Spirit, #Spirituality
Psychology for Dummies (53 page)
Our biological development begins with the process of sexual reproduction. So it goes that our psychological development begins as well as our behavior and mental processes are intrinsically tied to our biological development. For more on the relationship between psychology and biology see Chapter 3.
The process begins after a man and woman have had sexual intercourse:
1. The sperm and egg meet, combining their half-sets of chromosomes.
This is
fertilization,
and it occurs in the
fallopian tubes.
The fertilization process is delicate, and a lot of things can go wrong.
2. Twenty-four to thirty hours pass as a one-celled
zygote
(the fertilized egg) begins to divide itself.
This occurs in the fallopian tube as well. Through a process called
mitosis,
each chromosome makes a copy of itself and contributes the copy to the formation of a second cell. Cells continue to divide and multiply, repeating this process throughout fetal development. Fetal development is underway.
3. Three to four days pass while the fertilized egg travels to the uterus.
Upon reaching the uterus,
implantation
occurs. During implantation, the fertilized egg rests against the wall of the uterus and eventually merges with and becomes implanted in the lining of the uterus.
4. The
embryonic period
begins.
This occurs about 14 days after the
pre-embryonic stage,
or the
germinal period
starts. The
embryonic period
lasts until the end of the eighth week of pregnancy.
Getting a boostInfertility
can be caused by any number of complications, including older age, endometriosis, and pelvic inflammatory disease. Fertilization is a tricky business; healthy couples in their twenties can take, on average, up to a year to get pregnant. But modern medicine can perform some pretty impressive procedures to help nature take its course.
Artificial insemination
is a process in which a physician injects a man’s sperm near a waiting egg to help facilitate the meeting of the sperm and the egg. Some men have sperm that are unable to reach the egg deep inside the fallopian tube and need help making the journey.
In vitro fertilization
is a process in which a physician actually puts a sperm inside an egg, not leaving their meeting to chance.
5. Cells continue to divide.
The beginnings of a recognizable human take shape. The rudiments of the nervous system and other bodily systems are beginning to take shape.
th week through birth)
6. The
fetal period
begins and lasts until birth.
This begins in the third month of pregnancy. This final stage is an extremely delicate process. Psychological difficulties can sometimes be traced to problems in fetal brain and nervous system development. Mental retardation, learning disabilities, and other cognitive disorders are sometimes linked to fetal difficulties.
It’s extremely important for expecting mothers to maintain proper nutrition, avoid infectious diseases, and eliminate drug, alcohol, and tobacco use. These behavioral changes won’t guarantee the birth of a healthy child, but they certainly increase the odds.
The biological developments of each period are highlighted in Table 15-1.
Table 15-1 Fetal Development by Stage of Pregnancy Germinal (Weeks 0–2): What’s There? Amniotic sac Placenta Embryo Umbilical cord
Embryonic (Weeks 3–8): What’s There? Buds (arms and legs) Heartbeat Eyes and ears Nervous system Fingers and toes Spinal cord
Fetal (Weeks 9–36): What’s There? Organ systems working Sex organs Red blood cells White blood cells
Fetal: What’s Going On? Fetus is very active Fetus is sleeping like a newborn
It’s 36 weeks later, and some lucky woman has just given birth to a healthy child. Infancy is an exciting time in which both physical and psychological developments occur at an unprecedented rate. One minute, children do nothing but sleep, and the next minute they’re playing peek-a-boo.
For approximately nine months as a fetus, the newborn child relied almost exclusively on his or her mother for survival. This dependence doesn’t end with birth. Although the infant’s basic biological systems are functioning on his or her own, the maintenance of those systems requires the attentive care of a parent or primary caregiver. Sometimes, new parents can get overwhelmed with the responsibility of caring for an infant. The good news is that infants are born with a pretty impressive set of basic skills to help them survive.
In fact, nearly all of the most basic human survival skills are present at birth. When I say
basic,
I mean really basic — breathing, sucking, swallowing, and eliminating. Babies need to breathe to get oxygen. They need to swallow and suck to eat. They need to eliminate in order to cleanse their system. You nervous parents out there can rest assured that you won’t have to teach your infant how to suck on a bottle or a breast. It’s natural and automatic. It’s reflexive.
These skills are part of a broader list of innate reflexes infants are born with that aid in their survival. Here are a few more:
Rooting reflex:
Turning their heads in the direction of a touched cheek in an attempt to suck
Moro (startle) reflex:
Stretching out their arms and legs and crying in response to a loud noise or a sudden dropping motion
Grasping reflex:
Grabbing on to things, such as someone’s finger
One of the most anticipated areas of infant development for a lot of parents is their child’s motor development. Parents can’t wait to watch their child gain more and more prowess in his or her physical abilities. Infants have very little control over their limbs and head when they’re born. It takes time for the central nervous system and the peripheral nervous system to get things coordinated. The progression of control begins with control of head movements and then turns to control of the limbs and torso. Eventually, greater fine motor control kicks in. For example, children may begin to grab things with just two fingers. Table 15-2 shows this progression.
Table 15-2 Synopsis of Motor Development in Infancy Age in Months Abilities Present 1–3 Lifting head and sitting up with support 4–8 Holding head still and balancing it; looking around; using thumb to grasp; sitting up briefly without support 8–12 Coordinating hand activities; controlling trunk and sitting without support; crawling; beginning to favor the use of one hand over the other; sitting from standing position while holding on to something; walking with help, taking simple steps 14 Standing alone and walking alone without difficulty 18 Running and tumbling
As infants turn into toddlers, their motor behavior becomes more sophisticated. They can run, kick, throw, ride tricycles, and perform a variety of other complex motor-behavior sequences.
Fine motor skills,
increased dexterity and control over the use of their fingers and hands, continue to develop as they learn to manipulate small objects like cups, crayons, and small toys.
Finding out about full developmentTable 15-2 is not a comprehensive list of the development of motor abilities in infancy. For a more complete discussion of these abilities and most of the other aspects of development that I mention in this chapter, I highly recommend T. Berry Brazelton’s book,
Touchpoints: Your Child’s Emotional and Behavioral Development
(Perseus Press). Dr. Brazelton is a well-respected pediatrician with a lot of great ideas and observations pertaining to children.