While our working memory system maintains information for short periods of time – seconds or minutes – we also need to maintain information over much longer periods: hours, days, weeks, months, and even years. Researchers call this long-term memory. Most questions people have about their own long-term memories are prompted when there’s a failure. Why can’t I remember that person’s name? Where did I put my glasses? What’s the answer to number 7 on this quiz? Cognitive psychologists are interested in failures of memory but more broadly target memory organization (its structure) and memory operation (its processes). Of course, the hope is that once we figure these things out, we can answer more specific and individual questions like where your glasses are (have you checked your head?) or how to study effectively (have you tested yourself?). In this chapter we will first describe the structure of long-term memory: We’ll describe different types of long-term memory and their organization. In the next two chapters, we will describe memory processes of encoding (getting memory in) and retrieval (bringing memory back for current use).

A problem can be defined very generally as any situation in which a person has a goal that is not yet accomplished. That definition encompasses what we called decision-making. When psychologists talk about problem-solving, however, they typically mean open-ended problems in which the person knows the goal but nothing in the problem describes how to accomplish the goal.

In Chapter 6 we asked how explicit memory was organized (e.g., how does the concept for “bird” relate to the concept for “robin”), but we only briefly addressed the concepts themselves. This chapter focuses on how we represent categories in the real world by forming mental concepts. As we learn about the world, how do we decide which items belong in the same category? This chapter explores how we draw the lines that define categories and how we use mental representations to do other kinds of thinking.

In the last chapter we discussed the structure of language and introduced four levels of analysis. In this chapter we discuss how the process of language comprehension solves problems and resolves ambiguities. We’ll first describe these problems by asking, What makes language processing difficult?

When you are driving and your mind wanders from the song on the radio to the next left turn to what’s for dinner, do you pause in the middle to wonder what makes your mind wander? Probably not. Many people only contemplate how the mind works when their minds let them down. They contemplate memory (“Why can’t I remember the answer to this test question?”), attention (“I want to understand this material, so why can’t I keep my focus on my book and not on my phone?”), and vision (“How could someone think those two colors go well together?”). Questions such as “How does vision work?” seem somewhat interesting, but no more interesting than thousands of other questions about how the world works (How do viruses work? How do cell phones work? How do your lungs work?). These questions become interesting to most people when they consider how the answers might help their own lives.

Of all the cognitive functions your brain performs, vision is both the most remarkable and the most difficult to appreciate. It is difficult to appreciate vision precisely because it is so marvelous; your visual system works so efficiently, so effortlessly, that you have no clue what it is doing or how difficult its task is. Consider this: For decades we’ve had calculators that can perform long division far more quickly and accurately than any human. We also have computer programs that can beat 99 percent of the population in chess. Now, after years of work and millions of dollars spent, we are finally beginning to have computers that are able to recognize faces and drive a car.

These are all very practical decisions, and the methods of analyzing them make use of Principle 1:A dollar today is not worth the same as a dollar tomorrow. Economists have considered the management of personal financial resources over a lifetime to be a central issue worthy of serious study, and several Nobel Prizes in economics have been awarded for contributions in this area. And, as Box 3.1 shows, financial literacy for a nation’s people is a goal being pursued by countries all over the world.