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Perception and Interpretation in Criminal Justice

Psychological sources of error in juridical and public interpretation.

Key points

  • Research shows that officers are seen as much less competent when they mistake an innocuous object for a weapon and shoot the suspect.
  • Respondents knew the object may have been indistinguishable to the officer, but this did not influence their judgment of the officer's guilt.
  • This finding demonstrates a source of psychological disconnection between interpretation and perceptual reality in the criminal justice system.
Matthew J. Sharps
Source: Matthew J. Sharps

Many factors influence how jurors and others interpret a given incident in the criminal justice system.

In officer-involved shootings (OISs), for example, we have seen that the violent or nonviolent histories of suspects and officers can influence judgments of the events of the shooting itself, even though these histories are completely unrelated to the tactical realities putatively under judgment.

The sex of an armed suspect can alter opinions of officer conduct for men, but not for women, again without any real relevance to the juridical manner at hand; there are many such influences (e.g., Sharps, 2022).

These contextual factors can influence juridical proceedings in many areas, including the controversial realm of the OIS and beyond. There is continuity in the nervous system–such effects are not confined to this single realm of the criminal justice system. But how do they actually work? What are the cognitive processes involved in incorporating essentially irrelevant influences into our judgments?

One critical factor may lie in the representativeness heuristic (e.g., Kahneman & Tversky, 1972). This is because we frequently make judgments along prototypical lines rather than per the actual data in hand. An officer with a violent history seems like the kind of person who’d be involved in a wrongful shooting–he represents that sort of person, just as an officer forced to fire on a woman rather than a man may seem to represent a departure from traditional societal norms of conduct. The representativeness heuristic shows that we may judge people based on what they seem to represent rather than on what they actually did.

But to make this happen, there still has to be some level of cognitive slippage, some kind of mental disconnection to direct us away from the facts of a situation to interpretations that may not really be relevant to that situation at all. Does this type of cognitive disconnection exist?

Absolutely. For ninety years (Bartlett, 1932), we have known that memories are not static mental entities. Not only can elements of memory be lost–forgotten–but they can be entirely changed. Bartlett showed that memories, with time, become abbreviated and more focused on gist or core elements, with consequent loss of the important detail that might attach our memories more firmly to the realities on which they were based.

Bartlett also showed that our memories could be altered by our beliefs, beliefs which may have no basis in reality, and Loftus (e.g., 1979) was the first among many scholars to demonstrate this fact in the criminal justice realm. She showed that changes in the language in which questions were put to eyewitnesses altered their memories, changing what those witnesses believed into complete departures from what they had actually observed.

So, the information in memory on which we base our judgments is highly malleable and can be changed in the direction of what we believe. More recent research has even shown that the errors which accumulate as we repeatedly consider given memories can bias information still farther from reality. When witnesses were repeatedly asked to consider elements of crime situations, on the first inquiry, there were significantly more correct details than false ones–but by the third consideration, witnesses gave us slightly more errors than correct details (Sharps et al., 2012) and further inquiries weren’t much better. Mental errors–the type of “slippage” or disconnection suggested above–arise not only from external sources of contextual information (e.g., Loftus, 1979) but also from the mind's activity.

This was made extremely clear in a study of the interpretation of an officer-involved shooting (Lyons et al., 2019), in which respondents were asked to evaluate a police officer’s conduct in an OIS under two conditions: one in which the suspect was armed with a handgun, and one in which the suspect brandished a cell phone which was mistakenly identified by the officer as a weapon.

Tragically, this type of situation is astonishingly common. Under the stress of an armed encounter, people aim all sorts of things at the police, including, to the author’s knowledge, toy guns, toy rockets, shoes, wallets, power tools, and quite a few cell phones (see Sharps, 2022). Depending on the viewing situation and other factors, officers have, on several occasions, mistakenly fired on individuals wielding innocuous objects, with tragic consequences–hence the rationale for the 2019 study.

In that work, respondents found the officer significantly guiltier and less competent in shooting the suspect with the phone than the suspect with the handgun. However, across conditions, they did not find that the officer should have been able to distinguish the actual weapon from the cell phone. Respondents were aware that the gun and the phone may have been indistinguishable to the officer, but this crucial information did not influence their judgment of the officer's guilt.

The relevant information present in respondents’ minds was cognitively disconnected from the representational systems needed to evaluate what actually happened in the shooting situation. These results emphasize the importance of understanding internal cognitive disconnections in evaluating juridical decisions, in the increasingly important realm of the OIS and across the entire realm of the criminal justice system.

Thousands of detective stories, TV shows, and movies have given us a picture of the criminal justice system in which the facts of a given case are all important. This has perhaps provided us with yet another example of the representativeness heuristic–juridical judgment based on objective and unassailable facts. Yet as we’ve seen here, this concept is wholly oversimplified.

Public and juridical judgment in the criminal justice system may be influenced by context, language, personal beliefs, and even the activity of the mind itself. Ultimately, the importance of psychological factors in this realm and ongoing research to increase our understanding of these influences is difficult to overestimate.


Bartlett, F.C. (1932). Remembering: A Study in Experimental and Social Psychology. Cambridge

Kahneman, D., & Tversky, A. (1972). "Subjective Probability: A Judgment of Representativeness." Cognitive Psychology, 3, 430–454.

Loftus, E.F. (1979). Eyewitness Testimony. Cambridge, MA: Harvard.

Lyons, M., Carter, Z., McCaw, H., Jones, C., Botwin, M., & Sharps, M.J. Suspect Weapon and Judgment of Guilt in Officer-Involved Shootings. Society for Police and Criminal Psychology, Scottsdale, AZ, September 23, 2019.

Sharps, M.J. (2022). Processing Under Pressure: Stress, Memory, and Decision-Making in Law Enforcement. Park City, Utah: Blue 360 Media.

Sharps, M.J., Herrera, M.R, Dunn, L. & Alcala, E. (2012). Repetition and Reconfiguration: Demand‐Based Confabulation in Initial Eyewitness Memory. Journal of Investigative Psychology and Offender Profiling, 9, 149‐160.

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