A heuristics is a mental shortcut that allows people to solve problems and make judgments quickly and efficiently. These rule-of-thumb strategies shorten decision-making time and allow people to function without constantly stopping to think about their next course of action. Heuristics are helpful in many situations, but they can also lead to cognitive biases. The criminal justice system involves a complicated set of rules, roles and procedures, and professionals and laypeople alike are affected and can be overwhelmed by its enormity and Complexity. In particular, individuals who make decisions in the context of the criminal law Judges, magistrates, attorneys and jurors can be inundated with vast amounts of information they must consider in reaching the desired judgments, including complicated legal rules, Ambiguous facts and contradictory arguments about the application of the rules to the facts. Heuristics play important roles in both problem-solving and decision-making. When we are trying to solve a problem or make a decision, we often turn to these mental shortcuts when we need a quick solution. The world is full of information, yet our brains are only capable of processing a certain amount. If you tried to analyze every single aspect of every situation or decision, you would never get anything done.
In order to cope with the tremendous amount of information we encounter and to speed up the decision-making process, the brain relies on these mental strategies to simplify things so we don't have to spend endless amounts of time analyzing every detail. You probably make hundreds or even thousands of decisions every day. What should you have for breakfast? What should you wear today? Should you drive or take the bus? Should you go out for drinks later with your co-workers? Should you use a bar graph or a pie chart in your presentation? The list of decisions you make each day is endless and varied. Fortunately, heuristics allow you to make such decisions with relative ease without a great deal of agonizing. For example, when trying to decide if you should drive or ride the bus to work, you might suddenly remember that there is road construction along the standard bus route. You quickly realize that this might slow the bus and cause you to be late for work, so instead, you simply leave a little earlier and drive to work on an alternate route. Your heuristics allow you to think through the possible outcomes quickly and arrive at a solution that will work for your unique problem.
Some common heuristics include the availability heuristic and the representativeness heuristic. The availability heuristic involves making decisions based upon how easy it is to bring something to mind. When you are trying to make a decision, you might quickly remember a number of relevant examples. Since these are more readily available in your memory, you will likely judge these outcomes as being more common or frequently-occurring. For example, if you are thinking of flying and suddenly think of a number of recent airline accidents, you might feel like air travel is too dangerous and decide to travel by car instead. Because those examples of air disasters came to mind so easily, the availability heuristic leads you to think that plane crashes are more common than they really are.
Many decisions require assessments of probabilities that events occurred as claimed (e.g., how likely it is that the defendant’s version of the facts is true), and of the frequency with which particular events occur (e.g., how frequently a certain type of crime is committed). Relying on a heuristic in these situations is often simpler and less taxing than attempting to use all of the available and relevant information to make the assessment. For example, jurors making judgments about the likelihood of the defendant’s version of the fact and, by extension, about his guilt are likely to rely on a short-cut strategy termed the availability heuristic. The availability heuristic is used when one has to estimate the frequency or probability of some event. One way in which a person might estimate the frequency or probability of an event is to rely on the ease with which examples of that event can be retrieved from memory or imagined. Rather than methodically thinking through every possible instance of the event’s occurrences, the decision maker often chooses to use, or is only cognitively capable of using, what is available in memory to estimate the frequency or probability. If there are many instances of the event that are easily accessible in memory, then it is reasonable to infer that the event happens with some regularity. The disadvantage of using recall to estimate or judge the frequency of occurrence is that memory is notoriously selective: not all possible instances or examples of a particular situation will be committed to memory, and irrelevant or unusual examples may achieve a position of undue prominence in memory. In other words, variables other than actual frequency can affect accessibility. Thus, when the mental availability of an event is the basis for the frequency estimate of that event, the estimate will often be biased.
The availability heuristic can be used by jurors at any time during a trial. As they are listening to the evidence and deliberating with other jurors they may need to determine whether a particular event did, in fact, occur and if so, how often it occurred. But if the juror had been exposed to some kind of pretrial publicity about the event in question, that information may make the event highly accessible in memory and thus, particularly memorable. So the ease with which this event (or precise details about the event that may be important in assessing guilt) can be recalled from memory may be completely unrelated to its likelihood. In other words, jurors’ decisions may be based more on access to pretrial information than on any evidence related to this topic that was presented at trial. An example of the impact of pretrial publicity and its role in making some case facts highly available in memory comes from data reported by Vidmar (2002). Louise Reynolds was charged with murder in connection with the death of her 7 year old daughter in Kingston, Ontario in 1997. In the two year period that followed this incident, the local newspaper, the Kingston Whig Standard, printed 48 articles about the case, including many lengthy features, including and provided extensive coverage of the prosecution’s allegations against Mrs. Reynolds, its belief that she stabbed her daughter 84 times in the head. The paper also described the child’s tragic and abuse-filled life in some detail. The defendant’s alternate theory that the child was killed by a pit-bull found near the crime scene and covered in blood was corroborated by two forensic scientists, although this information was never printed in the local paper.
Information that is readily available to jurors can also affect a category of defendants as well as a particular defendant. Consider the vast amounts of air time and print lines devoted to alleged instances of corporate misconduct over the last few years the Enron, WorldCom, and Martha Stewart cases in the U.S. come to mind. Jurors’ perceptions of American blue-chip executives has likely evolved with the coverage in many jurors’ minds, corporate executives are all conspirators and crooks, out to steal from the little guy to line their own pockets. When an individual is accused of similar conduct it is possible, and perhaps likely, that jurors will have a readily-available stereotype in mind of how corporate executives behave, and categorize any particular defendant with those who have been widely discussed in the popular media. Personal experiences obviously affect the ease with which certain events can be brought to mind, and by extension, the likelihood that availability-based judgment biases will be present. Colwell (2005) recounts the story of a judge’s sentencing decision that was influenced by his personal experiences with the issues before him in court. This small town Pennsylvania judge sentenced a defendant charged with cruelty to animals to the maximum term of two years in prison, whereas the defendant in the following case, guilty of robbery for a second time, received probation. The discrepancy was apparently related to the fact that the judge had buried his pet of 14 years earlier that morning; this experience, highly salient and vivid in his memory, affected (some would say, biased) his sentencing decision.
Most victims and witnesses to crimes and accidents attempt to provide reliable details about their experiences. In similar fashion, most legal decision makers jurors, judges, magistrates, and attorneys try to set their personal biases and preconceived notions aside and make rational and fair minded judgments about information relevant to criminal justice. But just as victims and witnesses are sometimes hampered by their biased perspectives and by the frailties of human memory, so too, are legal decision makers sometimes stymied by fallibilities inherent in the judgment process. We have described several ways that the complexity of their decisional task can lead to intuitive, illusory thinking and ultimately, to biased decision making. We have shown how legal judgments, in particular, are influenced by short-cut, heuristical reasoning processes. We believe that by elucidating the psychological underpinnings of complex legal decisions we learn something very valuable about the ways that people really think about criminal justice and the law. From a base of understanding, we can begin to structure decision tasks to yield fairer, more predictable choices.