On paper, it’s one of the simplest math problems in the world: 2+2. If you’re counting something, like screws at the hardware store, it’s pretty straightforward. But the lines blur in other contexts.

The Hechinger Report covers one topic: education. Sign up for our newsletters to have stories delivered to your inbox. Consider becoming a member to support our nonprofit journalism. Students, parents ...

When searching for your flashlight in a tent at night, you must rely on tactile information to identify objects. The visual representation of the shape of your flashlight might facilitate your search.

Classical conditioning is a way to learn using unconscious associations. Pavlov discovered classical conditioning when dogs started to salivate at the sound of a bell before they got food. The ...