Erikson, Piaget & Psychology Theories & Concepts Explained

Vygotsky’s Theory: ZPD, Scaffolding, Play & How Culture Shapes Learning

Vygotsky’s theory of cognitive development proposes that learning is fundamentally a social process — children build knowledge through interaction with others, guided by cultural tools and more knowledgeable partners. At its core, Vygotsky’s sociocultural theory argues that what a child can do with support today, they will do independently tomorrow. This idea is captured in three key concepts: the Zone...

Conservation in Piaget’s Theory: 5 Tasks, Stages & Why Children Fail

Conservation in psychology is the understanding that quantity stays constant even when the appearance of an object changes. It’s one of six cognitive abilities children develop during Piaget’s concrete operational stage (ages 7–11) — the period when logical thinking first takes hold. Before conservation develops, children are routinely misled by how things look: a taller glass seems to hold more...

Concrete Operational Stage: Examples, Characteristics & Key Skills (Ages 7–11)

The concrete operational stage is the third of Jean Piaget’s four stages of cognitive development, spanning roughly ages 7 to 11. It marks one of the most significant transitions in childhood cognition: children move from intuitive, appearance-driven thinking to genuinely logical reasoning. The catch is that this logic is tethered to the physical world. Children reason well about things they...

Inner Speech: Vygotsky’s Theory of Thought and Language Development

Inner speech is the silent, internal dialogue that runs through your mind as you plan, reason, and regulate your emotions — and according to Lev Vygotsky, it doesn’t emerge spontaneously. It develops through a systematic process rooted in social interaction, gradually moving inward through childhood. In his landmark work on lev vygotsky thought and language, Vygotsky argued that language doesn’t...

Harlow’s Monkey Experiment: Why Baby Monkeys Chose Touch Over Food

Harlow’s monkey experiment was a landmark series of studies conducted by psychologist Harry Harlow in the 1950s that proved infant attachment is driven by contact comfort—the need for physical touch—not by feeding. Baby rhesus monkeys given a choice between a wire surrogate that provided milk and a soft cloth surrogate that provided none spent up to 18 hours a day...

Prosocial Behavior and Altruism: Definition, Examples & Key Theories

Prosocial behavior is any voluntary action intended to benefit another person or group — whether that means sharing lecture notes with a classmate, donating to a disaster relief fund, or pulling a stranger out of harm’s way. It sits at the center of how psychology understands cooperation, empathy, and moral motivation. While it’s tempting to assume people are naturally inclined...