It might be easy to say to yourself “I would never falsely confess to a crime.” Confessions are strong evidence that can have devastating, long-term consequences (e.g., imprisonment, probation, fines). However, 27% of exonerations after wrongful convictions involved a false confession. It might be hard to imagine why someone would falsely confess, so psycholegal researchers have been interested in identifying causes of false confessions. One important factor in false confessions is how police question a suspect (i.e., a custodial interrogation).
In “Why Suspects Confess: The Power of Outcome Certainty”, Yang and colleagues (2019) investigated why innocent people make the short-sighted decision to confess during interrogations. They hypothesized that false confessions are partially due to the certainty effect. According to the certainty effect, when making decisions, people overweight certainty because they tend to feel better about certain outcomes than possible outcomes. During an interrogation, a confession can lead to a more certain outcome, especially if the investigator makes the outcome of a confession appear to be certain (i.e., if you confess, you’ll get a good deal) and not confessing appear to be uncertain (i.e., if you don’t confess, this interrogation will continue and you face the probability of trial and possibility of conviction). Yang and colleagues (2019) predicted that the certainty effect would increase with longer interrogations.
In this study, college students were asked to admit or deny having previously engaged in 20 illegal/unethical behaviors during an interview. For each behavior, participants were given an option of an immediate “punishment” (completing a series of questions) or future “punishment” (meeting with a police officer to discuss their answers). But researchers varied whether admitting or denying resulted in the immediate punishment. Half of participants were given an option similar to a standard interrogation – they would get the immediate punishment if they admitted the behavior, but the future punishment if they denied the behavior. The other half of participants had the reverse (i.e., immediate punishment for denying; future punishment for admitting – punishment pairing manipulation). Researchers also varied whether the immediate punishment was certain (i.e., they must answer the questions every time) or uncertain (i.e., they sometimes had to answer the questions).
Participants confessed more when punishments paralleled a traditional interrogation (i.e., immediate punishment for admitting), indicating participants preferred the immediate, small punishment over the future, large punishment. Certainty of immediate punishment did not matter on its own. But when the immediate punishment was uncertain, the number of admissions did not vary based on punishment pairing. Thus, participants appeared to be more short-sighted when the immediate punishment was certain. Participants also confessed more later in the interview.
There are several concerns about the real-world implications of this study since researchers did not use actual suspects in a real interrogation. However, that sample is difficult to experimentally examine ethically. Although participants in this study were not suspects in an interrogation, the results still provide an important insight into the psychological mechanisms behind confessions. These results suggest that the interrogation format encourages confessions, especially long interrogations when a confessing results in a seemingly certain consequence.