What do Charles Darwin's evolutionary theories have to do with the reasons people commit crime?
Perhaps more than we realise, say a pair of Victoria University academics who explore the link between crime and human evolution in the new book Evolutionary criminology: Towards a comprehensive explanation of crime.
In the book, Dr Russil Durrant and psychology lecturer Professor Tony Ward argue that understanding patterns of offending requires an approach spanning wider than the offender's psychology and social and developmental background.
If we want to understand why men are much more likely to perpetrate crimes than women or why crime is often related to social and economic disadvantage, Dr Durrant said, then we have to consider "selection pressures" faced by our species in ancestral environments.
"Around 90 per cent of homicides are perpetrated by males and most of those are directed against other males," he said.
"We argue that humans largely follow a pattern of sexual selection similar to what we see in other mammalian species."
This included males competing for access to status and resources, which in evolutionary terms would have led to increased reproductive success.
"It is important to recognise, however, that there is nothing inevitable about male violence - although risk-taking and fighting is one way that males obtain status, there are alternative routes that separate us from other mammals, such as demonstrating skills, valuable knowledge and prosocial behaviour," Dr Durrant said.
"It would make sense, then, to focus on policies and programmes that enable males to pursue status through non-violent means."
Dr Durrant answered a few questions from the Herald about his research.
Is applying evolutionary theory been done before much in criminology or is this one of the first cases of it happening?
Evolutionary approaches have been pretty much neglected in criminology.
Although psychology now often incorporates evolutionary perspectives in its efforts to understand human behaviour, criminologists have largely ignored evolutionary explanations.
The book that Tony and I have written is the second book length treatment on the topic and there are a small number of scholars who have taken up this approach in criminology.
It is worth noting, however, that there is now an extensive literature on applying evolutionary approaches to understanding topics like aggression and violence in other disciplines such as psychology and anthropology.
Thus are main task is to provide a way of integrating this literature with mainstream criminological approaches.
Is this a big "missing puzzle piece" against other factors around offending?
We don't want to overplay our hand too much here.
Although we think that an evolutionary approach can advance our understanding of criminal behaviour - and related topics, like punishment - it is not going to replace existing explanations or approaches.
The question of what value an evolutionary approach adds is, however, obviously an important one.
Take the case of the relationship between adverse early environmental experiences - such as abuse, neglect, economic deprivation - and offending. Although we know that these are major risk factors for offending, it is not clear - I would argue at least - that we have a comprehensive grasp of why this is the case.
It may seem obvious, for example, that individuals from poorer backgrounds are more likely to offend because they have fewer opportunities for making a decent living compared to those who are less disadvantaged.
However, although some offending is clearly linked to economic necessity the relationship is less clear when we consider the elevated risk for engaging in various types of violent and sexual offences.
An evolutionary approach highlights how adverse early environments can shift what evolutionary developmental psychologists call "life history strategies" - harsh and unpredictable environments act as cues that indicate that the future is likely to be a dangerous and risky place and hence promotes greater risk-taking, intra-sexual completion, and - for males - "mating" effort.
When your chances of dying prematurely are greater, then - from an evolutionary point of view - it pays to engage in behaviours that promote reproductive success now rather than later.
These changes are likely to be reflected in higher rates of antisocial and aggressive behaviour.
The key point here is that humans have evolved to be flexible and certain environmental contexts can shift behavioural responses along more antisocial lines.
We think that an evolutionary approach, therefore, can actually help us to make a stronger case for the importance of policies that reduce poverty and inequality and that can effectively address child abuse and neglect.
Understanding why this is the case, we think, is essential for developing effective interventions.
How far are we going back when we talk about evolution in this context - centuries, thousands or millions of years?
If we want to understand the evolution of human behaviour then we need to consider the selection pressures that shaped both our physical characteristics and our behavioural characteristics since the lineage that led to our species split from the common ancestor of chimpanzees some five to seven million years ago.
Of course, evolution is an ongoing process so the more recent past is also important.
And, if we accept that culture can also evolve (which we do) then centuries and decades become important time frames to examine.
How can we physically measure or demonstrate that this plays a part in criminal behaviour? Is it possible or confined to theory?
Our main approach is to outline how evolutionary can help us to explain that patterns that we see in criminal behaviour.
For example, we know that men commit a lot more crime than women, that offending peaks during late adolescence, and is related to social and economic deprivation.
We think that a complete explanation of these findings - and others - requires us to consider both distal explanations - such as our evolutionary history - alongside more proximate accounts, like the characteristics of offenders and their social circumstances.
We, or anybody for that matter, can't prove, for example, that the tendency for males to fight each other much more than females in all cultures and all time periods reflects an evolutionary history of male-male competition that relates to reproductive success but this account helps us to understand why male-male violence is more common than female-female violence.
It is also consistent with other differences between men and women - for example, that men are more prone to risk-taking, are on average physically larger and stronger than women and so forth.
In this respect it helps us to understand a range of different findings not possible with other approaches, by themselves.
How directly relevant might this new research be to policy development?
One of the things that we would really like to emphasise is that taking an evolutionary approach does not commit us to the idea that our behaviour is genetically determined.
Humans are an enormously flexible species and this reflects, in part, the importance of culture and learning in shaping our behaviour.
When we think about crime, we know for instance that rates of homicide vary enormously both cross-culturally and over time.
Rates of homicide in Europe, for example, were over thirty times greater 500 years ago than they are now.
This reminds us that the evolution of norms, values, and institutions can affect the propensity of individuals - especially males - to engage in aggressive and antisocial behaviour.
An evolutionary approach adds value because it can tell us why, in this case males, engage in such behaviour in the first place - in a nutshell because it increases their social status and hence, in ancestral environments, reproductive success.
We argue that knowing this encourages us to develop programs and policies that can help allow us to create environments that enable men to pursue social status through more pro-social channels.
To take a very specific example, anti-bullying programs that simply promote "zero-tolerance" are not likely to be effective.
Once we recognise the "function" of bullying - to obtain dominance and social status - then we are in a position to provide alternative pro-social means that allow bullies to obtain this end without harming others.