Although the voices of professional psychologists became more numerous and audible in postwar America, they hardly constituted a monopoly on discussions about psychology and modern life. Other experts on human behavior, such as sociologists, psychiatrists, and anthropologists, offered their views to an eager public, as did various critics and commentators. The extent and variety of discourse on “the psychological society” seemed to indicate that psychology had moved to the forefront of public consciousness.

The notion that Americans lived in a “psychological society” took hold rapidly in the 1950s and had become a commonplace by the 1960s. Contemporary awareness of the changing social environment was stimulated by works that plumbed the meaning of modern life. Many commentators, both inside and outside academe, framed their analysis in terms of the relations between personality and culture. Among the first studies to appear after the war was David Riesman's evocatively titled book The Lonely Crowd (1950), which explored the personality characteristics of people living in a mass society, particularly the shift in the location of people's moral compass from within themselves (“inner-directedness”) to outside agents (“other-directedness”). His concern over the decline of individualism was shared by William H. Whyte, Jr., a writer for Fortune magazine. In The Organization Man (1956), he traced the rise of a set of values that privileged collective belonging, whether to a corporation, research enterprise, or other group.

Oral and literature cultures

In approaching this topic, I decided to start by discussing memory in oral cultures, which is what I call those without writing. Unlike many other scholars, I use the phrase ‘oral tradition’ to refer to what is transmitted orally in literate cultures. The two forms of oral transmission in societies with and without writing are often conflated, and that has been the case in the well-known work of Parry and Lord on the ‘orality’ of Homer. Most epics are products of literate cultures even if they are performed orally.

Oral performance in literate societies is undoubtedly influenced to different degrees by the presence of writing and should not be identified with the products of purely oral cultures. The point is not merely academic for it affects our understanding of much early literature and literary techniques, which are seen by many as marked by the so-called oral style. To push the point to a speculative level, speculative since I do not know a sufficient number of unwritten languages (and here translations are of no help whatsoever), many of the techniques we think of as oral seem to be rare in cultures without writing. Examples include assonance (as in Beowulf or the work of Gerard Manley Hopkins), mnemonic structure (as in the Sanskritic Rig-Veda), formulaic composition and even the very pervasive use of rhyme.

In his Vie d'Henri Brulard, the French novelist Henri Stendhal articulated the difficulties faced by an autobiographer endeavouring to recapture his life of thirty years earlier: ‘I make many discoveries … They are like great fragments of fresco on a wall, which, long forgotten, reappear suddenly, and by the side of these well-preserved fragments there are … great gaps where there's nothing to be seen but the bricks of the wall. The plaster on which the fresco had been painted has fallen and the fresco has gone forever.’ The richness of human life depends on our ability to remember the past, yet – like Stendhal – we are painfully aware of our memory's selectivity and vulnerability. Whether we are trying to recall particular details of our own lives, or to construct historical narratives describing broader cultural changes, we must all confront the gaps and distortions inherent in recapturing the past. This perplexing faculty, so central to our existence, exerts a universal fascination: as individuals, we wish to learn more about how our own memory functions; as members of society, we are concerned to appreciate the multiple ways in which our history is preserved. What we remember is intimately linked to how we remember, but innumerable approaches have been devised to explore that complex web of connections. The eight chapters in this volume, all by leading experts in their fields, transcend this diversity to address together the relationships between individual experience and collective memory.

Although she came to see me as an analytical patient five times a week, Miss A. found it very difficult to remember anything from one session to the next. Shortly after we had met and started working together, she had told me that she needed me to remember why she had gone into a shoe shop. It was not like going into a grocer's and forgetting the sugar – anyone could do that; she did not even know why she was in the shoe shop. She added, somewhat embarrassed by what she had said, that she did not need me to know it too well, that would be absolutely awful.

Mr B., on the other hand, had an excellent memory and prided himself on recalling what I had said more accurately than I did. But one day when I mentioned something it turned out he had forgotten, he snapped at me, ‘How can you expect me to remember that when I can't even remember my own mother from one day to the next?’ Mr B.'s widowed mother needed his daily attention. Mr B. had a particular memory of childhood that was probably what we call a ‘screen’ memory – a mixture of experience and highly relevant fantasy, like a dream image. In this mnemic image he was standing shaking out a tarpaulin sheet together with his father, a DIY enthusiast: he could see the garden, himself, his hands on the tarpaulin, the tarpaulin held at both ends shaking, and then the image stopped.

The brain's operation depends on networks of nerve cells, called neurons, connected with each other by synapses. Scientists can now mimic some of the brain's behaviours with computer-based models of neural networks. One major domain of behaviour to which this approach has been applied is the question of how the brain acquires and maintains new information; that is, what we would call learning and memory. Neural networks employ various learning algorithms, which are recipes for how to change the network to store new information, and this chapter surveys learning algorithms that have been explored over the last decade. A few representative examples are presented here to illustrate the basic types of learning algorithms; the interested reader is encouraged to consult recent books listed in the section on Further reading, which present these algorithms in greater detail and provide a more complete survey.

It is important to keep in mind that the models of neural networks that are simulated in computers are far simpler than the highly complex and often messy neural systems that nature has devised. Although much simpler, neural network models capture some of the most basic features of the brain and may share some general properties that will allow us to understand better the operation of the more complex system. Neural network models are built from simple processing units that work together in parallel, each concerned with only a small piece of information.

Although all of us experience memory failures at some time or another, these slips of memory do not cause severe disruptions to our daily lives. Most of us can still function adequately at work, engage in conversation, and remember the gist of the programme we saw on television last night, while accepting as normal the forgetting of certain details. After all, nobody remembers everything. For some people, however, their memory failure is of such a proportion that the effects can be devastating.

Imagine waking up and not being able to remember what you did yesterday. Imagine living in a time vacuum where there is no past to anchor the present and no future to anticipate. Such is the fate of many people suffering from organic amnesia. Although amnesia means literally ‘an absence of memory’, in practice people with organic amnesia do not have a total loss of memory. They remember who they are, they remember how to talk, and how to read, and they usually remember how to do things they learned before the onset of their memory loss, such as how to swim, ride a bike or play the piano. Unfortunately, they have great difficulty in learning new skills or information, experience problems when trying to remember ongoing events, and usually have a memory gap for the few days, weeks, months or even years before becoming ill.

In contrast, people with functional amnesia following, say, an emotional trauma, sometimes seem to lose memory for personal identity.

The biological importance of memory

It is not brains that make memories; it is people, who use their brains to do so. And animals, non-human animals, also make memories, and can learn and change their behaviour as a result of experience. Even some animals without much in the way of brains at all, just rather basic nervous systems, can do it. What this points to is the tremendous importance that the capacity to learn and remember has for the survival of animals. Plants do not need nervous systems, because all they have to do is to stand around with their arms – or branches – spread wide so that their leaves can catch the sun and photosynthesize. But animals which live on plants, and even more so animals which live on other animals, have to use their wits to find and capture their prey, and to avoid being eaten in their turn at least long enough to be able to reproduce. Such ways of making a living in the world demand the development of sensitive sense organs, and the capacity to register and interpret the data provided by those sense organs, to compare it with past experience and, even more, with the outcomes of that past experience. And this is what learning and memory are all about. It is not the only route to evolutionary success. After all, bacteria do pretty well without either brains or nervous systems, or even much by way of memory – though there have been some disputed claims that they can learn from experience.

I read somewhere that writers, or perhaps all artists, are haunted or hunted by unusually vivid memories of their early lives – as are the old, whose useful daily memories are decaying. Certainly I remember being obsessed as a child by a kind of ‘glittering’ quality about certain experiences, usually without deep importance in what I thought of as the narrative of my life – experiences excessively bright, strongly outlined, recognized so to speak as important, even when they were met for the first time. (Re-cognizedimplies memory, the existence of a former cognition.) It is not too much to say that these experiences were as tormenting as they were delightful, until I, the person who underwent them, formed the project of being a writer – because only the act of writing gave them a glimmer of the importance they had in life, and thus gave them a place, a form and an order which made sense of them. And which they seemed to ask for. Proust, at the beginning of À la Recherche du Temps Perdu, speaks of certain experiences which forced him to look at them – ‘a cloud, a triangle, a belltower, a flower, a pebble’ – and gave him, as a child, a sense of duty towards them, a feeling that they were a symbolic language which he ought to decipher.

Darwin's legacy

Charles Darwin is most famous as a natural historian, but his work had a profound influence on our understanding of memory because of his conception of biological time. Darwin set biology in a much longer context of time than had previous religious versions of creation and biological history, and so he created a puzzle: what is the relation of natural time, measured in millions of years, to the human historical time-frame in which we measure, say, the growth of classes or the development of cities in decades and centuries? Historical time seems a mere blip on the evolutionary scale. As the psychologist William James noted, our personal experiences of time are even more inconsequential in the Darwinian scheme of things, since personal events usually span mere days and months.

Moreover, Darwin gave natural time a distinctive character: he depicted it as conflictual and competitive. The concept of the survival of the fittest came late in Darwin's thinking, and he was ambivalent about the idea. He did not, like Alfred, Lord Tennyson, imagine nature ‘red in tooth and claw’, but he did think that what we call today an ecosystem depended on the ever-changing strengths and weaknesses of the species it contained, and that extinction and species failure were part of this natural order. Time is a destroyer as well as a creator.

In April 1991 ‘Cadbury World’ was opened by the then Prime Minister, John Major, in the multiracial city of Birmingham, England. ‘Cadbury World’ is a living museum, the museum of Cadbury, the celebrated Quaker family who established a world famous cocoa and chocolate business and made their name a household name. ‘Cadbury World’ replaced the factory tours and educational visits which Cadbury provided until 1970 on the Bournville site. After the factory was closed to visitors the firm received thousands of requests for information and finally decided to construct a purpose-built ‘experience’ – the chocolate experience – next to the factory. This chocolate theme park attracts half a million visitors a year. It combines an exhibition with a brief factory tour. It aims, in the words of the accompanying brochure, to ‘reflect the heritage of the UK's number one chocolate company‘.

It tells the story of Cadbury, the Quaker family firm which began in the 1830s as a small retail business in Bull Street, Birmingham, went through difficult times in the 1850s but by dint of the hard work of two Cadbury brothers was successful enough in the 1870s to warrant the purchase of extensive land in Bournville and build the ‘factory in the garden’, which became famous the world over. There the large modern factory was combined with a model village and community facilities to provide a whole way of life for Cadbury employees.