Skip to content
  • Blog
  • 4th Mar 2022

Being behaviourally-savvy about crime

The crime conundrum & the risk of getting it wrong

Countless theories have been proposed about why people commit crimes. ‘It’s peers’, ‘it’s poverty’, ‘it’s rational’, yet none of these ideas can consistently and adequately explain why crime happens in some instances, but not in others (Wikstrom, 2011). As seen in the first blog post, the evidence on crime is vast, but data doesn’t speak for itself and if we focus just on what is associated with crime then the list is almost endless. (For a light-hearted take, Stephen Sondheim has your back.) This list of correlates and theories they have spawned has been a significant barrier to progress in crime prevention. Wait, what? More information is a bad thing? Yes, because there are too many avenues to pursue meaning crime is over-determined. In short there’s not enough crime for all these theories to be correct. 

When factors become too numerous, we are in the hopeless position of arguing that everything matters”

– David Matza (1964)

The risk of getting it wrong in terms of why people commit crime is that we might end up pointing resources ineffectively, working with people in ways that might never lead to behaviour change because they are not causal, or develop and test interventions based on spurious relationships with crime. For example there is a correlation between homicide and ice-cream sales but it’s not a place we’d want to start building intervention ideas from.

Crime isn’t always about ‘the law’

Let’s start by asking a question that seems obvious but isn’t directly asked very often: what is crime? For many, ‘crime is what is against the law’. Sounds simple, but imagine something that is against the law now, and we come up with a theory to explain it and policies to prevent it. Later changes in culture mean that lawmakers decide it’s no longer against the law. If that seems far-fetched then consider that until 1967 sex between two men was illegal in England and Wales and there was a draconian set of punishments for those ‘guilty’ of it. But after the law changed, what was once illegal was then legal (for some). So what is a crime changes over time. This means we need to be recasting crime as something broader, and making our explanations broader as well.

Based on the work of P-O Wikstrom and colleagues, crimes are actions (or inactions that lead to crime). This also means that crime actions can be broken down into parts — or scripts — to understand what the steps leading up to a crime are, in the event these offer insights into how to prevent crime. At the risk of stating the obvious, crime is at its heart, a behavioural problem.

Most people don’t commit crimes most of the time because they don’t see crime as an option

Beyond the idea of crime as action, a useful way of thinking about crimes and the laws that create them is that they can be thought of as rules (Wikstrom et al., 2012). They’re a special sort of rule, written in law, but they’re rules nonetheless. This broadening out means we can also bring what we know from wider behavioural science into the problem of crime (and responses to it). By making crime ‘less special’ by reframing it as rule-breaking, we can ask questions like: what makes people more/less likely to follow or break rules? And what steps lead up to rule-breaking?

Ask yourself what rules you follow and why? For example, why not skip the queue, or take the wallet through the open car window, or punch the person who’s annoying you? For many of these situations, most people will not even perceive these options because their personal rules about right and wrong mean these alternatives are not considered, and even exposure to highly ‘criminogenic’ environments is unlikely to move them to crime.

But that doesn’t mean we could never do these things. You might be law-abiding most of the time, but under some circumstances you might be moved to violence, or theft. Consider these questions and the additional situations proposed:

  • Would you punch somebody? (What if they threatened your life or harmed you?) 
  • Would you steal food? (What if you were starving?)
  • Would you break covid regulations? (What if your boss encourages you to?)

In some situations we might think about and take courses of action that routinely would not come to mind. This tells us that crime isn’t just about people, but is about what situations people find themselves in as well.

Think about the following example: Could you ask someone for their seat on a train for no other reason than you want to sit in their seat, even if there are other seats available? The (in)famous psychologist Stanley Milgram asked his graduate students to do just that. His students reported just how hard it was. Milgram scoffed and had a go himself — and could barely get the words out to ask. Why was this so hard? Think through actually doing it — walking up to a total stranger sitting in a seat and asking them to move so you can sit in their seat. There’s no law against it, but it just feels ‘wrong’ and it requires a lot of effort (control) just to go through with it. This tells us that when an action contravenes our personal rules – or rules we perceive in a given situation – we may find it very difficult to follow through and it might require a lot of external pressure. 

Where crime is an option, self-control matters

If we accept that in some situations we might come to view rule-breaking as an option — skipping the queue, not paying at the barrier, stealing food, punching someone in the face — but we don’t follow-through it makes one ask: what’s stopping us? There are definitely more than a few explanations but one key element is self-control, a catch-all phrase but which generally means how well we can inhibit impulses, desires or delay gratification.

You’ll have read about self-control and its many forms — and there are those studies that stick in the mind, notably the marshmallow experiment. Rather than delve into arcane discussions of self-control and how to measure it, it’s safe to say that it’s one of the most heavily researched aspects of criminal behaviour. What we know from this body of research is that lower levels of self-control consistently predict a higher likelihood of criminal conviction, arrest and a whole host of other life outcomes.

This also tells us that people differ in their levels of self-control from an early age, and indeed we vary in our own ability to control behaviour depending on how tired or hungry we are. The good news is that self-control is to some extent malleable, at least early in life, meaning it might be improved through intervention.

When deciding on actions, we care whether other people see us and what happens if they do

But our behaviour isn’t only affected by our own restraint. Human behaviour is also influenced if we think we are being watched by others, as anyone actually being watched, or who notices a CCTV camera, or who is recorded by a police body camera, can attest to. A consistent finding is that not only are we affected by being observed but, particularly when being observed has undesired consequences that are quickly realised. In short, people are very likely to be deterred from acting if being observed quickly leads to being punished.

The three factors at play in deterrence are: (i) certainty of detection/sanction, (ii) celerity (speed) of punishment, and (iii) the severity of punishment. Of these, and importantly for crime-control, certainty and celerity seem to be more important than severity for deterrence, even for those convicted of more serious crimes. In other words, people need to know they’ll get caught, and the more quickly that happens the greater the deterrent effect may be.

But for some, no amount of external control matters

We can still point to situations where people have, seemingly ‘irrationally’, broken rules where it’s obvious they are being observed and will be punished – what’s going on? Consider the ‘habitual thief’, for example, someone who walks into a shop and doesn’t even consider paying for goods. Such individuals who are habitually anchored on rule-breaking may commit numerous offences. For individuals habituated to crime then it may take very high levels of external control — the figurative ‘policeman [sic] at the elbow’ — to make them deliberate on whether or not to commit a crime, but some may still do it anyway.

This suggests there is a small group of possibly ‘undeterrable’ criminals who commit disproportionate amounts of crime, which has some empirical support and seems to fit the Pareto principle (where 20% of the population account for 80% of crime). This matters for thinking about where to ‘place bets’ in terms of crime prevention efforts, but also for the type of intervention needed.


  • If you see that ‘x is a risk factor for crime’, ‘x is the reason for crime’, or ‘a large amount of variation in crime is explained by x alone’ — it might be a statistical artefact. There are literally thousands of crime correlates so focus on ‘modifiable’ risk factors stemming from systematic reviews of risk factors. (Risk factors studies are often WEIRD so it’s important to look at other studies like this one because what we think we know may not hold in different contexts).
  • Crime is about rule-breaking. What is or isn’t against the law changes all the time — but if we focus on what leads to rule-breaking then it simplifies the problem somewhat but also broadens the scope of what might be relevant beyond only what relates to crime explicitly.
  • Beliefs about right and wrong and self-control, are two important parts of whether crime happens (or not). These aren’t deterministic relationships but there is good evidence behind each of these.
  • Beliefs about right or wrong might matter more than controls (self- or external control). This is known as the ‘conditional relevance of controls’. For some, no amount of control is enough to prevent crime, for others, external controls are irrelevant (even wasteful) because they never consider crime as an option. This means we should think about who an intervention is likely to affect. If harsher penalties don’t deter those they are aimed at, even if they are popular and make for simple public discourse, then we should be looking for alternatives.
  • Crime is situationally variable – some situations may induce people to commit crime or may prevent crime. The better we understand the interplay between person and environmental interaction the better we’ll be able to design and implement interventions.
  • Crime is highly concentrated in individuals as well as places. A small proportion of the population are responsible for most crime, and a small proportion of criminals commit the majority of crimes. This means we can focus resources more sharply.

In the final blog post of this series we’ll talk about effective crime prevention strategies, the problems with establishing what is or isn’t effective, and the consequences of getting it wrong.


Want to learn more?