I distinguish three versions of the idea of a peculiarly female intelligence, each devised by men to explain and justify their superior social position. First, from Aristotle through to the nineteenth century, the difference was understood in terms of polarities, e.g., female intuition version male reason. Abilities such as abstract thought, considered alien to women, were seen as indispensable for grasping moral principles. Influenced by Darwin’s theory of evolution, Francis Galton replaced the polarities with a single continuous general intelligence (“natural ability”), which be believed was inherited by men and women. This second version granted women and men the same kind of intelligence, although women, on average, were believed to have less of it. In the early twentieth century, Louis Terman put an end to this view by eliminating particular items from the Stanford-Binet test so that the means of male and female intelligence were the same – otherwise, female means would, in fact, have been higher. A third version, promoted by the sexologist Havelock Ellis, again attempted to defend male hegemony by asserting that women have lower variability in physical and mental traits.

Chapter 1 aims to correct popular misinformation and summarizes how intelligence is defined and measured for scientific research. Some of the validity data will surprise you. For example, childhood IQ scores predict adult mortality.

Chapter 11 considers the spread of mass delusion and misinformation among humanity and its dangers.

Belief in biological races remains prevalent in the early 21st century despite opposing logical arguments and an abundance of converging evidence from multiple scientific disciplines. Structural and interpersonal racism, among the most salient issues today, are empowered and perpetuated by false claims and misconceptions about human origins, kinships, and differences. The best current science and historical knowledge make clear that races are cultural inventions that are not aligned with biological realities. Acknowledging the errors and falsehoods that provide the framework for biological race belief is not an attempt to deny real genetic variation or the importance of cultural races. This chapter reviews critical challenges to biological race belief and presents examinations of three of the most contentious and confounding race topics: IQ tests and intelligence, health and healthcare disparities, and sports as a popular source of misinterpretation and confusion. An evidence-based perception of humankind offers both laypersons and scientists a more productive position from which to understand our diversity and alleviate racism.

The chapter considers the range of features that enable investigators to describe a killing as ‘sexual’, such as clothes removed, objects inserted into the body and presence of seminal fluids on the body. Some killing done in association with sexual behaviour is not motivated by lust. For example, it might represent an attempt to avoid capture following a sexual assault or the accidental result of choking. Some killers reach orgasm from simply cutting a victim, while others (e.g. David Berkowitz) are sexually aroused by shooting a courting couple. The chapter describes a number of common features of a ‘composite killer’, such as cruelty to animals and voyeurism. Various ruses might be used in order to get a victim in the situation where he or she can be killed, such as offering a lift or seeking help. However, the most common method appears to be to engage the services of a sex worker.

Nearly everyone thinks that it’s your brain, and how it varies from the brains of others, that defines your intelligence as an individual. The terms ‘brainy’ and ‘intelligent’ are used almost interchangeably. If you really want to know about intelligence then you need to know about the brain. You may come across questions like ‘How does the brain give rise to intelligence?’ or ‘Where does intelligence reside in the brain?’. It is generally believed that knowing more about the brain will tell us more about intelligence, and much else, including human nature itself.

Aldous Huxley was not alone in pointing to ‘the most incredible miracles happening all around us … a cell in nine months multiplies its weight thousands and thousands of times and is a child’. Indeed, development strikes everyone as a wonderful, but mysterious, transformative process in which an insignificant speck of matter becomes a coherent, functional being. It all seems so automatic as to look like magic.

Intelligent systems have been a most crucial part of evolution. They furnished adaptability in complex, changing environments. As evolved in humans, our socio-cultural intelligence fostered the construction of shared worlds far beyond the inputs of our individual senses. That has allowed us to adapt the world to ourselves, rather than vice versa, as in all other species.

The dominant concept of intelligence is based on IQ, which is based, in turn, on the concept of the gene. Indeed IQ testing is very largely rooted in that concept. So, if I am trying to change the concept of intelligence in this book (which I am) it’s obvious that we must first tackle the concept of the gene.

The ideology surrounding intelligence has been two-fold. First, it has aimed to convince us that the social order is a consequence of immutable biology – that inequalities and injustices are natural and cannot be eliminated. Second, where problems cannot be ignored, it tells us to look for solutions at the level of the individual rather than the level of society. Undoubtedly, the story has been phenomenally successful. Nearly everyone, across the political spectrum and around the world, accepts it to some extent. A 2020 paper from the Foundation for European Progressive Studies supports that view. It reports a European survey of attitudes of the most affluent individuals to social inequalities. Although hard work and having a supportive family background are mentioned, educational aptitude and being ‘academically bright’ or intelligent are cited as the primary factors.

When people consider intelligence, they will first tend to think of IQ, and scores that distinguish people, one from another. They will also tend to think of those scores as describing something as much part of individuals’ make-up as faces and fingerprints. Today, a psychologist who uses IQ tests and attempts to prove score differences are caused by genetic differences will be described as an ‘expert’ on intelligence. That indicates how influential IQ testing has become, and how much it has become part of society’s general conceptual furniture.

Whether they believe in IQ or not, most people sense that individual differences in intelligence are substantial and at least partly ‘genetic’. The nature–nurture debate about the origins of such differences goes back a long way; at least as far as the philosopher-scientists of Ancient Greece. And most people have probably adopted common-sense views about it for just as long. It is evident today in popular cliches: our genetic blueprints set levels of potential, while nurture determines how much of it is reached; individual differences result from both genes and environments; genes and environments interact to determine individual differences; and so on.

Charles Darwin’s On the Origin of Species is a delightfully sophisticated account of evolution. But the core ideas are not that difficult to understand. Variations in traits in individuals arise by chance, due to what we now think of as mutations in genes. Some of those trait variations are functionally better adapted to part of the environment than others. Individuals so advantaged will tend to survive and leave more offspring. Accordingly, the advantage, and the frequency of the genes causing it, will increase from generation to generation. Conversely, genes causing less advantageous or harmful variations will decrease in frequency. That is natural selection.

So far I have tried to show how intelligence evolved at different levels according to the complexity of the environments faced. We have just seen how the breakthrough to cognitive intelligence emerged from the chatter between neurons in large networks. In this chapter, I show how human evolution involved another, even more stunning, breakthrough in a way not fully appreciated but fully consistent with biological principles. As with intelligent systems generally, it emerged from social interaction at a number of levels, not lucky genetic accidents.

Describes growing human health issues linked to exposure to a multiplicity of chemicals and mixtures. Impacts on the human brain, intelligence and mental disorders, autism, ADHD, depression, child and adult cancers, developmental diseases of children, sexual, gender and reproductive disorders, obesity and diabetes, ‘mystery’ disorders, re-emergence of ‘old’ conditions. The epigenetic curse. The case for precaution.