COMMON INVESTIGATIONAL FAILURES
Researchers have identified several common investigative failures over the past several decades through the careful analysis of past cases. Rossmo has identified those investigative failures in his book, "Criminal Investigative Failures" (Rossmo, 2009b). Investigative failures are organized into three broad categories: (1) cognitive biases, (2) organizational traps, and (3) errors in probability. Each of these is discussed here. Although these are found to occur among a wide range of criminal activities, it can be argued that sex crimes are highly susceptible to such investigative failures.
Cognitive biases include problems that occur as a result of inaccurate perception, inaccurate intuition, and/or tunnel vision. With regard to perception, Rossmo notes "perception is based on both awareness and understanding, we often perceive what we expect to perceive" (Rossmo, 2009b, p. 9). Humans are limited by their working memory, which has been shown in research studies to only hold five to nine items in our conscious memory (Rossmo, 2009b). Thus, while we are bombarded with multiple stimuli at any one time during any one incident, what we remember is quite limited. With regard to sex crimes, it is not uncommon for a victim's perception to vary a great deal from that of the alleged offender and even from the witnesses' accounts, if they exist. For example, an offender may perceive the victim was willing to engage in sex, while the victim believed it was rape.
Another cognitive bias involves intuition, or rather one's "gut instinct." Intuition relies on one's perception (usually derived through an automatic process) and reason (usually derived through a deliberate process). Intuition is prone to error, as it is influenced by emotion. Police officers often make intuitive decisions under chaotic conditions and do so quickly. Such intuition is susceptible to error. Only under a slow methodical analysis of reliable information are decisions less prone to error. Humans are prone to taking cognitive shortcuts, especially when presented with incomplete information. This often leads to error (Rossmo, 2009b).
Another cognitive bias that can occur, especially in a criminal investigation, is tunnel vision. This occurs "when there is a narrow focus on a limited range of alternatives" (Rossmo, 2009b, p. 13). With regard to the type of work to which police officers are exposed, they can quickly eliminate the actual offender and/or quickly narrow their focus on an innocent person (Cory, 2001). Tunnel vision can also affect a victim's account as well. The victim may remember the gun that was pointed at her, in great detail, but not be able to identify the race of the offender.
These cognitive biases (inaccurate perception, inaccurate intuition, and tunnel vision) can lead to problems in evaluating evidence, such as ignoring context and misjudging a situation. For example, a police officer can mistakenly shoot someone jogging after a robbery is reported. The police officer fails to recognize the context—the person was in jogging clothing on a jogging trail and not involved in the robbery.
Confirmation bias can also occur, which involves paying attention only to information that corroborates one's theory and ignoring any information that discredits the theory. Additionally, research shows that individuals are more influenced by vivid information, as opposed to data and statistics (Heuer, 1999). Thus, eyewitness description (which can be inaccurate) carries a lot of weight. Police officers can also fail to account for a lack of evidence. For example, a missing bottle of the victim's favorite perfume, given by an ex-boyfriend, can easily be overlooked (Rossmo, 2009b).