Introduction

Memory is the mental faculty that lets us hold on to and later bring back information we have taken in — from a phone number we need for the next thirty seconds to the poem we memorised as a child and can still recite decades later. It is not a side skill; it sits underneath almost everything else the mind does. Perceiving the world, thinking through a problem, and making a decision all depend on being able to hold information in mind and connect it to what we already know. Because of this central role, psychologists have long tried to answer four linked questions: how does new information get committed to memory in the first place, how is it kept over time, why is it sometimes lost, and what can be done to make memory work better. This chapter takes up each of these questions in turn — first examining what memory is and the models psychologists have proposed to explain how it works, then looking at why forgetting happens, and finally at practical ways to strengthen memory. The scientific study of memory is over a century old. The German psychologist Hermann Ebbinghaus is usually credited with the first systematic investigation, publishing his findings in 1885 after running memory experiments on himself. He found that we do not forget material at a steady, even rate — the loss is rapid at first and then slows down considerably. Many other researchers built on this early work, and their contributions are introduced through the chapter wherever they are most relevant.