One of the best known psychologists of the 20th century was Jean Piaget. The memory he described was from when he was about 2 years old, a kidnapping attempt in which his nurse tried to protect him. According to the storehouse metaphor, memory is kind of a warehouse. When one remembers an event from one’s life, one looks through this warehouse. Remembering a past event is also a kind of simulation, a simulation of what happened in the past, rather than a veridical reproduction of the past. In fact, our best understanding is that brains are massively parallel simulation devices. Constructive theories deal with filling in gaps at encoding as the event transpires, whereas reconstructive theories deal with filling in gaps at retrieval as one tries to remember the event. When thinking about memory illusions it is important to make a similar distinction.

Insomnia is a complaint of difficulty falling asleep or staying asleep that impairs the functioning or causes distress. So, compared to a bout of poor sleep, insomnia is a sleep problem that takes on a life of its own. Basically, it is persistent, unsatisfactory sleep that has daytime consequences. When insomnia occurs at least three nights per week and lasts for three months or longer, it is technically called “chronic” insomnia. People with insomnia report low mood, irritability, poor concentration and memory, reduced physical well-being, and some difficulties interacting with other people. They also report having more fatigue-related car crashes than people without insomnia. People with insomnia seem to be able to perform mundane tasks of daily living but they tend to have less enjoyment of their activities and show less “cognitive flexibility”—they tend to think more narrowly and less creatively—than people who sleep well.

This introduction presents an overview of key concepts covered in the subsequent chapters of this book. The book discusses human memory: how it works, how it sometimes doesn’t work, why it’s important, and why it’s interesting. It explains the role of trauma in memory and the complex set of loss of function and preserved function that occurs in amnesia. The book talks about whether one really needs a superior memory in the first place. Memory is intrinsically interesting because it involves a re-experiencing of the past in the present. Researchers have found that many of the same brain regions involved in perceiving an event become active again when one remembers the event. Memory teaches us about other things and other human beings. Memories can serve to define ourselves to others. And memory can also serve as a kind of control on our emotions.

Based on public opinion polls, a substantial number of people worldwide don’t only think about aliens, but think they exist and have visited our planet. The aliens are defeated not by man, but by nature: they are killed by exposure to Earth’s bacteria. The War of the Worlds was massively more popular in helping the image of “aliens” become ensconced in our cultural consciousness. The story of Betty and Barney Hill is both an archetypal story of an otherworldly encounter and the prototypical story of an alien abduction. One of the popular television programs on the History Channel is Ancient Aliens, which purports to use archaeological and historical analyses to demonstrate how human culture and development has been extensively shaped by contact with extraterrestrials. The claims of governmental conspiracies over a crashed unidentified flying objects (UFO) and ancient visitation from aliens have both been thoroughly examined and found wanting.

This chapter focuses on one particular type of eyewitness memory the memory of an eyewitness for the face of the perpetrator. Eyewitness identifications are crucial evidence in upward of 80,000 criminal cases per year. Accurate eyewitness memory can help police catch criminals and can help prosecutors bring solid cases against those criminals. The person accused of a crime also deserves to have justice done to not be falsely accused or wrongfully imprisoned. To understand eyewitness memory, one has to understand perceptual psychology, cognitive psychology, social psychology, motivation, emotion, reasoning, personality just about every kind of psychology we can imagine. Mistaken identifications are a memory problem. They involve a person retrieving details from memory but being mistaken in the recollection of those details. The good news is that cognitive and social psychologists have been hard at work in developing science-based approaches that can reduce the problem.