Random

Walks smoothly, rides push toys using feet, unzips large zippers, and uses a spoon.

2-3

Runs with minimal control over stopping or turning, pedals and steers a tricycle, buttons a large button, and copy a straight line.

3-4

Runs smoothly with control over stopping and turning, skips, uses a fork, and copies simple shapes and some letters.

4-5

Throws and catches a ball, rides a bicycle with training wheels, ties shoes, copies numbers and simple words.

5-6

Miguel has always enjoyed music and he sings and plays his guitar in the public square whenever he can sneak away from his family's business.

Active gene-environment correlation

Aurelia is a cute and cheerful baby. Everyone smiles when they see Aurelia and most people talk baby talk to her.

Evocative gene-environment correlation

Around the world, infants follow an age-related sequence of motor development, from crawling, to walking, to running.

canalization

For Halloween, a couple dressed their chihuahua in a bumble bee costume. Seeing the stripes and wings, their 3 year old daughter Ava now thinks the dog is a bee.

centration

Graduating from high school

chronosystem

Dr. Yang studies cross-cultural differences in body maturation and growth, including differences in body size, proportion, appearance, health, and perceptual abilities.

contextual

Four year old Jessica asks her mother, "How do I put this on?" while she is in a different room than her mother. Her mother asks her what she is trying to put on, because she cannot see what Jessica is doing.

egocentrism

Availability of funding for school to provide classroom resources

exosystem

Internal organs begin limited functioning.

first

Regular contractions of the uterus begin.

first

cervix dilates from size of cheerio to size of bagel

first

During lunch, a mother gives a graham cracker square to each of her young children. She gives her son Darrius a whole graham cracker square. For her younger daughter Amari, the mom breaks the square into two pieces for easier eating. Though he watched his mom prepare the crackers, Darrius gets upset because he believes his sister received more cracker than him.

irreversibility

Cultural beliefs about the value of education

macrosystem

Reading at home improves performance of reading at school.

mesosystem

Family

microsystem

As baby Sanjay's physical development improves, he is able to crawl around and explore his environment, advancing his cognitive development. His newfound crawling skills also contribute to changes in Sanjay's psychosocial development. For example, he may experience anger when he picks up a breakable object, only to have one of his parents take it away.

multidimensional

Allison is approaching her 60th birthday. She realizes that her eyesight and hearing are not as good as they used to be, and when visiting her daughter in graduate school, climbing the stairs to the fourth floor has become more difficult. However, Allison has also become more patient over the years, is better at solving difficult problems, and has a more confident and favorable view of herself than she had in her 20s and 30s.

multidirectional

Bailey is a graduate student in clinical psychology. As part of their training, Bailey works with children and families affected by autism. Each week, Bailey participates in a team meeting that consists of a school psychologist, social worker, speech and language therapist, and nursing students.

multidisciplinary

Four-year-old Sam's parents are both coaches and manage a gym during the summer months. Sam has been exposed to sports since they were a baby. Sam recently started soccer and has also been enrolled in swimming lessons. Sam is already demonstrating strong athletic skills, despite being very young.

passive gene environment correlation

Following a stroke that affected his balance and muscle strength, Jose participated in 3 months of physical therapy. Today, Jose feels as strong as he did before the stroke and walks at least ten miles a week for exercise.

plastic

Although both of his parents are 5 feet 6 inches tall, 17-year-old Theo is 6 feet tall. He is healthy and has been well nourished since birth.

range of reaction

Over the past week, Varun has been trying to learn to tie his shoelaces. Initially, his mother held his hands and worked his fingers through the process. Now that Varun is better at it, she only guides him verbally.

scaffolding

Baby exits the birth canal.

second

External body features like fingernails and eyelashes develop.

second

Fetal movement can first be felt.

second

The fetus is covered with vernix caseosa.

second

woman is encouraged to push

second

Placenta separates from the uterine wall.

third

The growing fetus puts pressure on maternal organs and disrupts sleep and digestion.

third