Investigative psychology is a problem-solving psychology set up to deal with real-world crimes and other issues, beyond the abstractions of university laboratories. Investigative psychologists collect, assess, interpret, and organize the information available from an investigation. It is an emerging area of criminal psychology that utilizes psychology to bring together various data relevant to investigations to improve information on which an investigation is based, inferences related to that information (growing out of offender profiling), and the psychology of investigative decision- making. The findings, in turn, influence decisions that can be effectively supported. This field of psychology originates in studies of criminal activity, especially serious crimes, and has been utilized in a wide range of situations from examining the location of the improvised explosive devices in Iraq, identifying unqualified individuals attempting to gain welfare benefits, examining behavior in emergencies identifying the sources of anonymous offensive letters, to controlling crowds. This article provides an account of the origins of investigative psychology and describes the frameworks drawn on to make inferences about an unknown offender or criminal group or network from how, where, and when crimes are committed. It also explores the ways that investigative approaches are changing as a result of input from investigative psychology.
Origins of Investigative Psychology
The idea that modern, scientific psychology can be of value to those investigating crimes has a long history. One of the founders of modern psychology, Hugo Munsterberg, wrote On the Witness Stand in 1908 about psychology and crime over a century ago and Sigmund Freud gave advice to judges about distortions in memory. But the idea that psychologists can help solve crimes came into popular culture through fiction when Thomas Harris’s book The Silence of the Lambs (1988) became a successful major film in the early 1990s. From that point forward, there has been an enormous amount of speculative writing that implies a clever psychologist can get into the mind of a violent criminal to solve crimes that flummox detectives. This has confused the reality of psychological contributions to investigations as these fictional accounts owe far more to the notion of fictional detectives such as Sherlock Holmes and many other subsequent fictional detectives than to any real scientific activity.
The real-life origins of current investigative psychology are usually linked to David Canter’s contributions in 1986 to a major investigation in London related to a series of rapes and murders. Canter worked from simple principles drawn from social and environmental psychology that assisted the police to narrow down the range of possible suspects they had identified. However, many other researchers had been exploring interview procedures and the detection of deception prior to this as well as other areas of psychology relevant to the work of detectives. Consequently, in 1991, these various areas were brought together under the umbrella term investigative psychology.
Beyond Offender Profiling
Examples of making inferences about an offender on the basis of the actions related to a crime go back at least to biblical accounts and have always been present in law enforcement. However, the development of a formal framework that allows empirical testing of the validity of these inferences requires the elaboration of the inferences as a search for the relationships between the actions in a crime and the characteristics of the offender, often referred to as the A → C equation, or profiling equation. Solving this equation requires an identification of the salient actions in a crime, which can include time, date, and location, as well as a clear definition and measurement of these. It also demands a focus on those features of the offender that are of utility to the investigation. Many studies have therefore been carried out to identify the co-occurrence of criminal actions within a subset of criminal activity. These studies have now covered the full gamut of crimes, including arson, burglary, hostage taking, murder (serial and single), rape, and terrorism. It is important to note that contrary to crime fiction, it is rare to find simple one-to-one relationships between actions and characteristics. The situation in which the crime occurs will have an influence on what the perpetrator does. Furthermore, offenders may learn from previous criminal experience and change their actions accordingly.
In general, a 4-fold framework has been established that covers, mutatis mutandis, all crime types explored so far. These have been linked to dominant narratives that underlie criminal actions, providing a theoretical basis for the inference process. These narratives are professional, adventure, victim, and tragedy. The emotional components of the criminal’s experiences have also been correlated with these dominant narratives. Further, some crimes are more likely to be associated with one narrative than another; for example, many burglaries by young offenders are characterized as adventure, whereas many homicides are typically expressed as tragedies by their perpetrators.
The narrative framework allows the development and testing of hypotheses about the relationships between actions and characteristics. Although this research is in its early stages, results are emerging that provide the possibility of taking account of both the contingencies that influence an offender’s actions and the likely development of those actions over criminal careers.
Geographical Offender Profiling
One area that has proven particularly susceptible to empirical scientific study has been the examination of the associations between where a crime is committed and where an offender is likely to be based. This is often referred to as geographical offender profiling and is of particular relevance to perpetrators who commit a number of crimes, often referred to as serial offenders. Although many people are aware of the existence of people who murder a number of strangers over a period of time (i.e., serial killers), most perpetrators of crime commit more than one crime. Many burglars, for example, commit hundreds of burglaries. Geographical offender profiling is a special aspect of the aforementioned profiling equation. In this case, the actions are the crime locations and the characteristics are, typically, where the offender lives at the time of the offending. Studies of geographical offender profiling are revealing a considerable amount about the propensities of criminals as well as feeding directly into police investigations. The success of this research is due to the increasing availability of police geographical information systems in which the data are more precise than details of what actually happens in a crime. However, police geographical data are still far from wholly accurate, making many approximations necessary.
In general, two aspects of an offender’s geographical activity have been identified. One is propinquity, which dictates that as the distance from the offender’s home increases so the likelihood of a crime occurring decreases. This is known as a decay function because the reduction in the probability that a crime will be committed is more rapid the farther the crime location is from the home. However, this decay pattern is only found when examined across a number of different offenders, known as the aggregate level. It is rare to find that any one serial offender decreases the frequency of crimes at increasing distances from home.
The second is the morphology of the crime locations. In a large number of cases where offenders commit two or more crimes, and where the opportunities for crimes are evenly distributed around the home, the base of the criminal tends to be within the area circumscribed by those crimes. A simple way of modeling this is on a map, taking the two crimes farthest from each other and drawing a line connecting them that serves as the diameter of a circle. The hypothesis, often supported, is that the home will be within this notional circle. This is not to claim offenders think in terms of a circle of operation but rather to demonstrate a simple process for defining an area of criminality.
These two aspects of crime geography— propinquity and morphology—have been combined into decision support systems, such as one called Dragnet, to carry out analyses on crime series as guidance to investigators. This contributes to the third component of investigative psychology mentioned in the opening paragraph—the psychology of investigative decision-making and how those decisions can be effectively supported. Rather than just generating interesting findings, investigative psychologists take the further step of converting those findings into processes and systems that can be directly used as part of a live investigation.
Linking Crimes to a Common Offender
All inference processes benefit from having information about more than one crime committed by the same perpetrator. The linking of crimes to the same person also assists law enforcement activities and obtaining a conviction in court. Therefore, a growing area of investigative psychology is exploring the possibility of linking crimes in the absence of forensic evidence, such as DNA, fibers, or witness descriptions.
In general, the proximity of crimes has been found to be the best predictor of crimes being linked. This follows from the propinquity principle because if crimes are close to the home they should be close to each other. This works well for rare, serious crimes, such as serial stranger rape and murder, but is less effective in areas that have a high density of frequent crimes such as burglary. Other markers, notably the similarity of actions in a crime, are therefore being investigated.
Effective Investigative Information
Without the initial stage of obtaining information about the crime being effective, no further aspects of finding culprits or proving their guilt are possible. Therefore, investigative psychologists contribute to the collection, assessment, and organization of the information available to an investigation. This includes improving the interview process, detecting deception, and considering such matters as false accusations and false confessions.
There have been great strides in recent years in understanding the investigative interview process. This has grown out of studies of memory and its essentially constructive process as well as a more thorough understanding of the interpersonal transactions that are the essence of one person asking another questions. From these studies, an awareness of how malleable human memory is and the possibilities for genuine, inadvertent distortions have been revealed. These understandings have given rise to proposals for psychologically influenced interview procedures, notably the cognitive interview and the UK police forces Prepare, Engage, Account Clarification, Closure, Evaluation interview protocol. However, although these have strong theoretical roots, there are many challenges to carrying out these processes in practice.
The other area of information retrieval that has been extensively studied is eyewitness (and to a lesser extent earwitness) identification. The results of these studies challenge many popular assumptions about the ability of people to recognize a culprit after a crime has been committed. For example, the confidence eyewitnesses exhibit about their memory and/or identification of a culprit does not represent a simple relationship to the accuracy of that identification. Furthermore, a number of studies have shown that people can be led to genuinely think they remember something that has not happened. This investigative psychology research has helped cast doubt on many aspects of law enforcement procedures. The importance of this has been demonstrated in major revisions of many guilty verdicts that have become possible through developments in DNA identification. A high proportion of people convicted because of eyewitness testimony have been eventually found not guilty.
Supporting Effective Investigative Decision-Making
The mission of investigative psychology to contribute to law enforcement processes raises the requirement for psychological research results to be fashioned into decision support systems. As already mentioned, Dragnet and similar geographical profiling systems, while primarily research tools, are an example of a growing number of processes and computer-based systems developed to aid law enforcement. However, for these to be effective, an understanding of investigative decision-making processes is necessary. Therefore, an increasing number of studies are exploring police decision-making.
Many of the studies focusing on the work of investigators draw on cognitive psychology, especially the study of decision heuristics. These have found, for example, that the confirmation bias is not uncommon in police investigations. This is the process of seeking information to support what is already believed to be the case rather than material that may disprove it. It has also become apparent that in those jurisdictions where police sometimes violate human rights, training in investigative psychology can provide an alternative, much more humane set of strategies and tactics for carrying out law enforcement. One powerful example is the demonstration that torture is of little value in obtaining useful information. Carefully prepared interviews built on developing relationships with suspects, victims, and witnesses are much more fruitful.
Investigative Psychology as a Coherent System
The three interrelated areas of information retrieval, inference, and decision support form a coherent investigative psychology system. Poor information cannot be used for effective inferences. Those inferences are no use if not formulated in a way in which investigators can act. Taken together, these open up a psychological approach to the consideration of criminality. Thinking of criminals as ordinary people doing illegal things provides a very different perspective from past dominant clinical psychology viewpoints that understood criminals to be odd, disturbed, or mentally ill. This was behind the Federal Bureau of Investigation claim that profiling was only relevant to motiveless crimes. In contrast, investigative psychology has been applied to common crimes like burglary and fraud not just the bizarre and extreme crimes. It is applicable to a wide range of investigations, far beyond crime, that is broadening all the time.
References:
- Canter, D., & Youngs, D. (2009). Investigative psychology: Offender profiling and the analysis of criminal action. Chichester, UK: Wiley.
- Youngs, D. (Ed.). (2013). The behavioural analysis of crime. Burlington, NJ: Ashgate.