top of page

Psychology — Driver of Innocence Reform

The Innocence Scholarship Column May 31, 2023

Innocence scholarship serves several goals. Social scientific research (including history) helps to explain the innocence movement, for example, through public opinion surveys about attitudes toward exonerees. A bewildering variety of forensic sciences are improved through technical forensic science research. Legal research advances judicial doctrines and legislation that facilitate truth finding and also works to improve the excruciatingly complex and slow process of exoneration.

These research paths are all essential to advance the innocence movement. Yet, in my view, psychology is the most important discipline to develop the knowledge and techniques that have the best chance of reducing wrongful convictions.

A few qualifications are in order. First, a surprising amount of innocence research is interdisciplinary; so, along with “pure” legal, forensic science, or psychological research, much important scholarship combines disciplines in several ways. Second, “psychology” is a shorthand for psychological science. Its branches most relevant to wrongful convictions are applied cognitive and social psychology. Insights from developmental and evolutionary psychology and neuroscience are also important. A prime example are studies of cognitive bias among forensic scientists, a subject for a later column. Third, some innocence research by psychologists might be called “forensic psychology,” but that is mainly a practice field, which for example examines a defendant’s mental condition. Finally, the practice of clinical psychology can provide valuable services for exonerees who suffer the psychological effects of wrongful convictions.

Why is psychology the essential driver of innocence reform? Improving forensic science is not relevant to the vast majority of serious crime convictions where forensic science plays no role. Also, psychological research has uncovered cognitive bias in forensic science that can lead to erroneous conclusions. As for the law, psychological research undermined the belief that criminal verdicts, despite many criminal procedure safeguards, are close to perfectly accurate. We have learned that psychological approaches are often better than purely legal or law enforcement methods to obtain accurate results.

The classical example is the accuracy of lineups. A century ago psychologists knew that many eyewitness facial identifications were inaccurate but had no recommendations for improvement. The Supreme Court’s ruling that required defense lawyers to be present in some lineups did little to help. Wrongful convictions occurred in spite of defense cross-examination of eyewitnesses in trials. Innocent defendants often pleaded guilty after an honest but mistaken eyewitness picked them out of a (flawed) lineup.

Real change began to occur in the 1970s. Cognitive psychologists, applying advanced theoretical research about how the mind recognizes patterns, began to conduct controlled experiments on students. These studies isolated factors that could lead to more or less accurate identifications. The great benefit was that the “ground truth” was known. Subjects were shown a contrived crime. In later lineups, the researchers knew whether the subjects identified the perpetrator or selected a foil from a lineup where the perpetrator was present. Even more unsettling, foils were selected in perpetrator-absent lineups, as happens in many wrongful convictions.

The research began to pile up. By the mid-1990s more than 2,000 studies were published in peer-reviewed journals. The psychologists now had enough knowledge to advance practical suggestions on how to improve lineups. The backstory of these scientific advances, how the psychologists got the ear of Janet Reno (US Attorney General in the 1990s), and how Reno set up a process to introduce these new ideas to resisting prosecutors and skeptical police is told in a wonderfully entertaining and informative page-turner by James Doyle, entitled True Witness: Cops, Courts, Science, and the Battle Against Misidentification (Palgrave Macmillan, 2005). The book is easily obtained through online booksellers.

Doyle, a Boston lawyer, is an active and innovative participant in the innocence movement; I’ll write more about his work in future columns. He brought an arresting set of credentials to the writing of True Witness. As co-author of a lawyer’s treatise and reference volume on eyewitness testimony with Elizabeth Loftus and other leading eyewitness researchers, he was steeped in knowledge about the century-old struggle between lawyers and psychologists to improve eyewitness identification and the scientific work that led to the breakthrough about lineups. As the lone defense lawyer in a working group set up by Janet Reno to advance eyewitness guidelines, Doyle was the fly-on-the-wall in a room filled with cops, DAs and scientists who argued for months about new ideas that threatened to upset a familiar world.

I’ve read a lot of technical books and articles about eyewitnesses and lineups over the years but Doyle’s readable account was most helpful for creating perspective. Future columns will delve into the many ways that psychological science has been critical to advancing the goal of reducing the number of wrongful convictions.

Copyright © 2023 Marvin Zalman


bottom of page