6.1 Introduction

This chapter examines current and past biological approaches to the study of crime and behaviour. Biological theories allow criminologists to differentiate between the effects of environment, lived experiences, and genotype on antisocial behaviour and understand how the two interact; to evaluate the impact of stress on the epigenome and how adverse experiences in childhood may have lasting effects in adulthood and beyond; to understand how the impacts of lived trauma can be passed to the next generation; to demonstrate how equating a heritable factor with a behaviour or outcome without considering the social implications of the heritable factor has led to systemic discrimination and abuses; and to evaluate the protective factors that have been identified that could be valuable in treatment and intervention.

Origins of Biological Explanations

In the past, many people believed that almost all behaviour, including criminal behaviour, was based on biology alone with no room for environmental influences, yet these beliefs had no basis in fact or science; they were simply politically, and often racially, motivated. Furthermore, many non-criminal issues, such as poverty, destitution, promiscuity, and even masturbation, were considered inherited behaviour. None of these early beliefs had any basis in science.

In the 18th and early 19th centuries, physician Franz Gall believed that the shape of a person’s head reflected the shape of the underlying soft brain, indicating which parts of the brain were responsible for different behaviours. This was called phrenology, and while it is obviously absurd, it acquired an almost cult following in the Western world, even though there were strong critics. Many of Gall’s “facts” were based on observations of just one person; for example, a lump on the head of an animal torturer suggested cruelty (Niehoff, 1999). Eventually, the scientific communities managed to convince the public that phrenology was false science. Nonetheless, an Italian criminologist by the name of Cesare Lombroso, often considered the father of criminology, performed “experiments” comparing the features of criminals and non-criminals (forgetting of course that many people are falsely convicted of crimes and many who commit crimes are never caught) and stated that certain features or atavisms were indicative of a born criminal, such as twisted lips, protruding jaws, large noses, sloping foreheads and even environmental features such as tattoos (Baum, 2011; Niehoff, 1999). Lombroso believed that such people were inferior, “morally, mentally and physically” (Niehoff, 1999, p.8), and, as they were born that way, they should be punished due to their perceived threat. These beliefs, along with the assumption that they could never be helped, led to the frightening ideas of biological positivism and determinism, even if someone never actually committed a crime.

Although these theories began to fall out of favour, people still incorrectly believed that tendencies toward poverty, destitution, and petty crime were biologically inherited. Certain powerful people, led by English eugenicist Francis Galton, began to suggest that the poor who had very large families were contributing to crime, and it was suggested that the poor should be “dissuaded” from having children and that the “better” members of society (e.g., richer, upper classes) should be encouraged to reproduce. This was called positive eugenics, but it rapidly devolved into negative eugenics in which people considered “unfit” were actively prevented from reproducing through forced sterilisation (Kupferman, 1991; Niehoff, 1999). This movement became incredibly popular in the United States, with Americans terrified that the large number of immigrant families flocking to its shores would overwhelm them, neatly ignoring the fact they had done the exact same thing to the Indigenous populations who had existed on Turtle Island for millennia. Immigration laws were passed that allowed new immigrants from “undesirable” countries to be sterilised before entering the country. Some were forced to take IQ tests in a language they could not understand and were sterilised for being “inferior” if they failed, resulting in cultural genocide. Similar movements existed in Europe, peaking in the Nazi genocides of Jews and other groups during World War II. As the rest of the world began to acknowledge these atrocities, support for eugenics faltered; however, eugenics persists in our modern world with the continued, coerced sterilisation of Indigenous women in vast numbers in the 1970s and still continues to this day right here in Canada (Ataullahjan et al., 2021) (see Indigenous women in Canada are still forcibly sterilised – report).

In response to the horrors of eugenics, many criminologists ceased exploring biological impacts on behaviour, wary of anything that suggested determinism, focusing instead on environmental impacts. In the words of Denno, for the past 30–40 years, most criminologists have not even been able to say the word “genetics” without spitting (Denno, 2011, p.972).

Unfortunately, because the past was rife with systemic racism that ensured privilege to some, often justified with references to faulty or false scientific findings (known as pseudoscience), efforts to explore the true relationships between behaviour, biology, and environment have been delayed. Biology alone does not determine our behaviour, but then neither does the environment. Even the old dichotomy of nature versus nurture is wrong—neither act in a vacuum. Instead, behaviour results from complex interactions of both our biology and our environment. Human behaviour is certainly influenced by factors such as our genetic background, our body and brain chemistry, any trauma or damage our brain may receive during life as well as pollutants and toxins to which we are exposed. However, all these factors are also influenced by our environment. In fact, much of our biology is plastic and has evolved to be shaped and changed by our experiences.

It must, however, be clearly understood that any biological or environmental influence over a behaviour is only that—an influence. Neither biology nor environment cause crime, but a certain biological or environmental influence may increase a person’s predisposition to exhibit criminal behaviour. This is merely a predisposition and does not mean that a person will commit a crime, any more than having a medical predisposition for a heart attack means that a person will necessarily have a heart attack. A change in diet or lifestyle may greatly reduce the predisposition. That is the beauty of studying biological influences on criminal behaviour: so many predispositions can be managed by a change in environment, peer influence, medication, or lifestyle.