How do people react to the world around them as they get older? How do they adjust to new desires or new social surroundings? At what age do people generally go through a new stage of cognitive development?

Erikson's Theory of Psychosocial Development

There are eight stages that a normal, healthy human should go through starting from when they are an infant to their late adulthood. With each new stage that a person goes through comes a new challenge usually built off of the previous stage and learned techniques. If the person does notsuccessfully complete a stage, it may show up as a problem in their later life.

The stages

Approximate Age
Virtues
Psycho Social Crisis[2]
Significant Relationship[3]
Existential Question[3][not in citation given]
Examples[3]
0–2 years
Hopes
Basic Trust vs. Mistrust
Mother
Can I Trust the World?
Feeding, Abandonment
2–4 years
Will
Autonomy vs. Shame and Doubt
Parents
Is It Okay To Be Me?
Toilet Training, Clothing Themselves
4–5 years
Purpose
Initiative vs. Guilt
Family
Is It Okay For Me To Do, Move and Act?
Exploring, Using Tools or Making Art
5–12 years
Competence
Industry vs. Inferiority
Neighbors, School
Can I Make It In The World Of People And Things?
School, Sports
13–19 years
Fidelity
Identity vs. Role Confusion
Peers, Role Model
Who Am I? What Can I Be?
Social Relationships
20–39 years
Love
Intimacy vs. Isolation
Friends, Partners
Can I Love?
Romantic Relationships
40–64 years
Care
Generativity vs. Stagnation
Household, Workmates
Can I Make My Life Count?
Work, Parenthood
65-death
Wisdom
Ego Integrity vs. Despair
Mankind, My Kind
Is It Okay To Have Been Me?
Reflection on Life
Hopes: Trust vs. Mistrust
Erik Erikson's theory begins with the start of human life and the basic needs of an infant that are met by the parents. The infant's first interactions and moments with his parents are the building blocks of their first steps of trust and mistrust. If an infant experiences no affection or neglect from their parents at this early of an age, the infant's feelings towards the world will be mistrust. This can lead to a child being withdrawn in the future.