Imagine a world in which you decide to have your body frozen in order to be revived in 500 years, by when a cure for death may have been discovered. You might have your body placed in a special facility. But suppose that the facility is damaged by war or natural disaster? A lot could happen in 500 years. So you decide instead to design a robot to carry your body around and keep it safe. The robot will need to be programmed to protect you against all possible hazards. Now you have a new problem: you cannot anticipate all the situations that the robot may have to deal with. So you decide to give the robot a high level of intelligence so that it will be flexible enough to think out solutions to the problems that it may confront. The robot is still a tool for your preservation and might well be expected to sacrifice itself to that end. For example, it may need to transfer you at some point to a new robot of superior design. However, there is a snag. You have programmed the robot with the ability to think for itself. What if it starts to pursue its own objectives rather than yours? What if the robot rebels?
The robot is, of course, really you and its designer is your genes. In The Selfish Gene, Richard Dawkins urged us to think of evolution in terms of replicators (genes) and vehicles (organisms). Genes do not serve the purposes of organisms; it is the other way around. The organism is programmed to carry, and serve the interests of its potentially immortal passengers, the genes. For many this idea conveys a depressing, if not alarming, message. It conflicts with all religious beliefs and seems to challenge our deepest intuitions about free will and humanity. Keith Stanovich, a distinguished experimental psychologist, also advocates the selfish gene hypothesis but with an interesting twist that applies only to human beings. Combining the selfish gene with recent theoretical developments in cognitive psychology, he argues that we are only just beginning to comprehend the implications of evolutionary theory.
There is a strong and varied body of evidence to support the idea that human beings have two distinct cognitive systems. One of these is evolutionarily ancient and works in similar fashion to the functioning of the brains of higher animals. Stanovich calls this system Tass - the set of autonomous subsystems. Tass functions are automatic (not requiring conscious thought) and enable us to process huge amounts of information. We effortlessly recognise faces, understand spoken utterances, maintain our balance while walking and so on. Such functions require complex control systems in the brain that are either genetically pre-programmed or have been learned from interactions with the environment.
The second system, which Stanovich calls the analytic system, appears to be unique to modern humans. Humans alone can engage in abstract analytical reasoning and entertain supposition and hypothesis. We often make decisions without conscious reflection, relying on Tass processes to reflect our earlier learning, in the same way as animals learn to respond to their environment. For example, we might avoid one dish in a restaurant because we disliked how it was cooked on a previous visit. But we can also use our analytic thinking system to override a habitual response arising from past experience. We may have heard that a new chef has been employed and calculate that he will not make the same mistakes that caused our negative experience with that particular dish. Analytic thinking, however, is sequential and very limited in capacity, so it is just as well that Tass can take control of most of our behaviour, most of the time.
How and why modern humans developed the ability to think for themselves is an evolutionary mystery. There are discontinuities in the archaeological record about 50,000 years ago, indicating that Homo sapiens (alone among all other species of man) suddenly displayed the ability to modify the design of artefacts for a changing environment and the ability to think metaphorically, with the emergence of art and religious symbolism. Although no clear evolutionary drivers for these changes have been identified, they followed a period of rapid brain development and the probable emergence of language.
Stanovich distinguishes what he calls evolutionary rationality - acting in such a way as to serve the interests of the genes - from instrumental rationality: acting in such a way as to fulfil the goals of the vehicle. The two often coincide, as it is in the interests of the genes to protect their hosts, at least until the latter have had time to reproduce and raise their offspring. However, they also often diverge. One reason for this is that we live in a world which differs significantly from the environment in which we evolved - known as the environment of evolutionary adaptation, or EEA for short. For most of our evolutionary history we were hunter-gatherers in a range of often hostile and hazardous natural environments. Our craving for fat and sugar was adaptive in the EEA because food was scarce and the ability to store energy in fat cells aided survival. But in modern western society, pursuing this goal of the genes may endanger our health. Only by use of the analytic thinking system - with its access to theoretical knowledge about the effects of diet - can we inhibit or override these cravings and decline to purchase the chocolate bar. Of course, despite our best intentions, Tass often triumphs in this kind of situation. Pursuing vehicle goals may also involve frustrating genetic goals. For example, the genes made sex pleasurable for individuals in order to encourage procreation and gene replication. As vehicles, however, we frequently practise sex with contraception, thus pursuing our own goal of pleasure while frustrating the goal that the genes "meant" it to serve.
Rationality is a central and recurring theme in The Robot's Rebellion. Experimental psychology has demonstrated many kinds of cognitive biases, but the analytic thinking system can be used to override biases arising in Tass.
Stanovich attacks a controversial group of evolutionary psychologists including Cosmides, Tooby and Gigerenzer. One of their mistakes, he argues, is to overestimate the extent to which evolutionary processes have resulted in self-contained "modules" for the control of human behaviour, and correspondingly to overlook the highly general learning and reasoning abilities that people possess. They hardly seem to recognise a role for the analytic system at all. Tass processes favour the fulfilment of short-term goals and immediate gratification. But is it rational to smoke a cigarette, eat a hamburger or initiate an affair with an attractive student without using the analytic system to compute the consequences for our long-term goals?
Stanovich shows that irrationality can arise from the analytic system as well as Tass. He devotes a chapter to Dawkins's concept of "memes." Like genes, memes are selfish replicators, but they take the form of beliefs and desires that are reproduced through social exchange and influence. There are good memes that help us by reflecting true knowledge of the world about us. However, many memes have self-replicating and defending properties and do not serve the interests of their hosts. Memes conveyed by advertising may persuade us to buy branded products at twice the price of unbranded ones of equal utility. Memeplexes - systems of memes - can be self-defending, as in religious belief systems whose teaching includes resistance to criticism and rejection of alternative beliefs. Thus human rationality also needs the analytic system to provide critical reflection on the memes we acquire daily, in order to discard the useless or harmful and retain the beneficial.
The Robot's Rebellion is a fine book which might radically alter your view of yourself and the world around you. Although he covers a wide range of scientific ground, some of it quite technical, Stanovich maintains a fluent and accessible style. Here we have a first-rate scientist who is concerned not simply to communicate his knowledge to a wider audience, but also to stress its social implications. It is central to his view of rationality that people must understand their evolutionary history, their status as vehicles of their genes and the cognitive architecture of their brains.
