developmental-psychology

How Harry Harlow's wire-mother and cloth-mother experiments with rhesus monkeys overturned behaviorism's model of love, and why the ethical cost still matters.

The Sally-Anne task revealed that around age four, children develop the ability to understand that other minds hold beliefs that differ from reality. Here is the science.

Gibson and Walk's 1960 visual cliff showed that crawling infants refuse to cross a perceived drop even over solid glass. The experiment settled a century-old debate about innate depth perception.