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Thinking about the law like a psychological scientist

Before psychological scientists design studies and collect data, we need something to study. That is, we need questions to answer. For researchers like us, specialists in psychology and law*, these questions are usually related to the legal system. But where specifically do we get our ideas? In some cases, they are the result of applying our scientific knowledge and training to a topic; in others, we see an event or case and want to know more about it.

Kitty Genovese's murder inspired a program of social psychology research
One place we get our ideas is from real-life events, like criminal cases. Sometimes these are cases that are reported widely by the media; sometimes they are cases we encounter in the course of our work. Cases that seem to defy common sense make us ask questions about how they could have happened. A prominent example of a crime inspiring research is the infamous murder of Catherine “Kitty” Genovese. Kitty was murdered in 1964 in Queens, New York in a brutal attack that occurred over a time period of about half an hour. Press coverage of her murder suggested that several dozen eyewitnesses failed to intervene or call the police as she was attacked. Although it later emerged that this reporting about the number of eyewitnesses was incorrect**, the notion that large numbers of people could fail to intervene in an emergency sparked the interest of researchers John Darley and Bibb Latané.

It’s shocking that so many people could see an emergency unfolding and do nothing. Many social commentators at the time opined that modern society made people callous. But perhaps it was instead something inherent in the situation that made people less likely to intervene. Darley and Latané started a program of research on the conditions in which bystanders are more or less likely to intervene in emergencies or when others are in distress1. Much of this research comprises experiments in which participants – who are unaware of the true nature of the study – witness an urgent situation and must decide, without prompting, whether they will intervene and assist. The researchers can control many variables in the situation, including the number of bystanders, the nature of the emergency, and who is in distress. This research has found that, contrary what common sense might tell us, as the number of bystanders in the area increases, individual bystanders are less likely to intervene and a person in distress is less likely to receive assistance overall2.

We are also often compelled to conduct research by cases of wrongful conviction. Consider the case of Juan Rivera, who was wrongfully convicted of rape and murder in 1993, partly on the basis of a false confession which had been obtained after a lengthy and stressful interrogation***. Rivera had a strong alibi and DNA evidence recovered from the victim did not match him. But despite the exculpatory evidence, the prosecution charged Rivera and offered an implausible argument to explain the lack of a DNA match: that the 11-year old victim had consensual sex prior to being assaulted by Rivera, who must have failed to ejaculate (and failed to leave any physical trace at the scene). At three separate trials, Rivera was found guilty, and he spent a total of 19 years in prison before being exonerated.

How is that people can be convicted, even in the face of such strong exculpating evidence? This case and others like it**** inspired researchers Sara Appleby and Saul Kassin to conduct studies in which people acted as jurors in simulated cases where all of the evidence and facts were the same, save variations in how the attorneys argued the case. They found that improbable prosecutorial theories that attempt to explain exculpatory evidence, like the one used in Rivera’s trial, can be remarkably persuasive to jurors3. Put another way, a prosecutor suggesting a crazy story may very well tilt the trial against the defendant. This may be because people greatly try to understand complex information (like evidence in a trial) with coherent stories, and the prosecutorial theories, though vanishingly unlikely, provide a way of understanding the apparent inconsistencies in the evidence (e.g., a confession and DNA evidence that conflict).

Sensational and counter-intuitive cases compel important questions about how apparently extreme events can occur, but common legal and law enforcement practices can also inspire research, especially if they are based on untested assumptions or if we don’t understand them very well. For example, last week we wrote about our research project related to bait questions – a common interview technique in which an interrogator asks a suspect about hypothetical evidence (which may not actually exist). That project got its start a couple years ago when we shared an office at John Jay College as the result of a conversation during some downtime.

As Timothy remembers it*****, he was complaining about bait questions to some other colleagues in the office. He had recently run a training course for law enforcement and military interrogators, and he found that many of them repeatedly used bait questions in the training interrogations. His intuition was that something seemed problematic about them, but he struggled to clearly identify what it was. Overhearing the conversation, Will pointed out that bait questions sounded a lot like the way researchers suggest misinformation to participants in memory studies – a field of research that had never been applied to interrogations in this way before. We thought it might be possible that bait questions, despite being hypothetical, might lead people to believe the suggested evidence really existed, like a classic misinformation effect. We then put our heads together and planned the first of our studies on how bait questions could influence memory4.

Alternatively, we might draw from past research or psychological theory and try to apply it to issues in the legal system. That is, we might start with a practical problem in a legal context, and then we try to use what we already know from psychology to solve that problem. One of the most successful examples of researchers applying well-established psychology to a real-world problem is the Cognitive Interview. Witnesses and victims often have difficulty remembering details of what they experienced – after all, memory is rarely perfect. The Cognitive Interview was developed by Ron Fisher and Ed Gieselman, as a technique for enhancing witnesses’ memory5.

The Cognitive Interview comprises a series of interviewing techniques based on our theoretical understanding of how memory works. The ability of a person to remember something depends on at least two things: (1) the quality of the information stored in a person’s mind (what psychologists call a “memory trace”) and (2) the circumstances under which the person is trying to retrieve the memory (what we call the a quality of the “retrieval cues”). To understand what this means, imagine a memory is a printed photo, in one of several albums. The photo can be clear, or it can be fuzzy and faded (this is like the quality of the memory trace). If you’re looking for a specific picture, regardless of the quality of the photo, it can be easier to find it if you’re already looking in the right album (this is like the quality of the retrieval cues).

When we interview a witness, we don’t have control over how good their memory trace is. However, we can try to optimize the conditions of retrieval. From classic memory research we know that people can remember more information when they have already mentally accessed information related to what they’re trying to remember – that is, people can use related information to “cue” their memory. For instance, it’s easier to remember what the place you grew up was like if you catch a whiff of a familiar smell from your childhood (like freshly baked cookies or newly cut grass)6. Based on this idea, Cognitive Interview includes a technique called mental context reinstatement, which involves having the witness actively recall the sensory experience of the event – what they saw, heard, smelled, and felt to use as memory cues for other relevant information.  Dozens of experiments have demonstrated that this tool can assist witnesses in remembering substantially more details about what happened. In this way, our general knowledge of memory helps to solve a specific, applied problem in the justice system.

Beyond the ones we discussed here, there are plenty of other sources of inspiration for researchers. What all these sources of research ideas have in common is that they raise unanswered questions in psychology and law. Once we have a question, we can apply our scientific knowledge and training to design and conduct an experiment to find an empirical answer. Yet each experiment we conduct starts with a common core – curiosity. Anything that stokes curiosity can be the beginnings of research, whether a newspaper story, law article, or chapter in a psychology textbook. In this way, you do not need to have a PhD in order to do research. You just need to want to know more about the world around you.

This post was written by Timothy Luke and Will Crozier

* The intersection of psychology and law is also sometimes called legal psychology or forensic psychology. Unfortunately, these terms are used inconsistently, and there’s little agreement on what to call ourselves.

** Kitty Genovese’s case is too complicated to explore thoroughly here. For an interesting read about the complexity surrounding her murder and the subsequent investigation, see Kassin, S. M. (2017). The killing of Kitty Genovese: what else does this case tell us? Perspectives on psychological science12(3), 374-381.

*** “Stressful” is something of an understatement. After the interrogation, Rivera had an apparent psychotic episode and repeatedly slammed his head against a wall in jail, while the police typed a confession for him to sign.

**** In rape cases in which DNA recovered from the victim does not match the defendant, prosecutors often argue that the DNA must have originated from another subject – possibly another consensual sexual partner or someone else who participated in the rape but was not caught. These arguments are often highly improbable, yet they appear in numerous cases – so many that people have taken to calling it the “unindicted co-ejaculator” theory.

***** As a case study in how fickle memory can be, Will and Timothy can’t quite agree on the details of what he was complaining about.


[1] Darley, J. M., & Latané, B. (1968). Bystander intervention in emergencies: diffusion of responsibility. Journal of personality and social psychology8(4), 377-383.

[2] Fischer, P., Krueger, J. I., Greitemeyer, T., Vogrincic, C., Kastenmüller, A., Frey, D., ... & Kainbacher, M. (2011). The bystander-effect: a meta-analytic review on bystander intervention in dangerous and non-dangerous emergencies. Psychological bulletin137(4), 517-537.

[3] Appleby, S. C., & Kassin, S. M. (2016). When Self-report Trumps Science. Psychology, Public Policy, and Law22(2), 127-140.

[4] Luke, T. J., Crozier, W. E., & Strange, D. (2017). Memory errors in police interviews: The bait question as a source of misinformation. Journal of Applied Research in Memory and Cognition6(3), 260-273.

[5] Memon, A., Meissner, C. A., & Fraser, J. (2010). The Cognitive Interview: A meta-analytic review and study space analysis of the past 25 years. Psychology, Public Policy, and Law16(4), 340-372.

[6] Easterbrook, J. (1959). The effect of emotion on cue utilization and the organization of behavior. Psychological review66(3), 183-201.


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