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Writer's pictureC. Edward

The Misinformation Effect: The Malleability of Human Memory and Investigative Interviewing



Elizabeth Loftus, a preeminent psychologist and memory researcher, has made significant contributions to our understanding of human memory, particularly in the realm of how memories can be altered or distorted. One of her most notable contributions is the study of the "misinformation effect", a phenomenon where a person's recall of episodic memories becomes less accurate due to post-event information (Loftus, 2005).

Brain sketch
Sketch of brain

The Foundational Study


Loftus' first major study on the misinformation effect was published in 1974, in collaboration with John Palmer (Loftus & Palmer, 1974). In this experiment, participants watched film clips of car accidents and were then asked questions about what they had seen. The researchers varied the language used in the questions, particularly the verbs used to describe the car's interaction (e.g., "smashed," "hit," "collided"). They found that the language used in the question influenced participants' memory of the event, including their estimates of the cars' speed and whether they recalled seeing broken glass, which was not present in the footage.


Later Research and Expansions


Loftus and her colleagues continued to research the misinformation effect, demonstrating its power in a variety of contexts. Loftus, Miller, and Burns (1978) altered a key detail of a witnessed event in one study. Participants saw a series of slides depicting a car stopping at a stop sign before hitting a pedestrian. Some were later exposed to a misleading suggestion that the sign was a yield sign. Those who received the misleading suggestion were more likely to remember the sign as a yield sign, demonstrating the robustness of the misinformation effect.


In another significant study, Loftus and Pickrell (1995) expanded on the misinformation effect by demonstrating that entirely false memories could be implanted into individuals. Participants were made to believe that they had been lost in a shopping mall as a child – a completely fabricated event. The study highlighted the extent to which misinformation could alter existing memories and create new ones.


Implications and Relevance


The results of this study were significant, not only because they illustrated the misinformation effect but also because they provided critical insights into the fragility and malleability of human memory. The findings suggested that memory isn't a perfect recording of events; rather, it is subject to influence and can be easily distorted. This understanding has broad implications, particularly in legal settings, where witness statements and ultimately testimony can heavily influence the outcome of a trial.


Best Practice Investigative Interviewing


In an investigative interviewing context, post-event information can have devastating effects on interviewee statements and case outcomes. Investigators must use proper questioning techniques, interviewing best practices, and sound evidence disclosure strategies to avoid giving witnesses post-event information through leading questions or investigator comments.


  1. Separate interviewees – Separating witnesses is a crucial procedure in investigative contexts to prevent "witness contamination." When multiple witnesses discuss an event amongst themselves, there's a heightened risk of one individual's account influencing another's, leading to contaminated testimonies. This confluence of recollections can introduce inaccuracies, as witnesses may unconsciously incorporate details from others' narratives into their own memory of the event. By keeping witnesses apart, investigators can ensure that each account remains individual and untainted, preserving the purity and reliability of each testimony. This not only increases the chances of obtaining accurate information but also upholds the integrity of the investigative process.

  2. Leading Questions - Leading questions play a pivotal role in the misinformation effect, a phenomenon where individuals' memories of an event are altered by misleading post-event information. The Cognitive Interview (CI) (Fisher & Geiselman, 1992) has primarily centered on optimizing interviewing techniques and specifically warns against the use of leading questions. These questions are phrased in a manner that subtly prompts or suggests a specific type of answer. For instance, by asking, "Did you see the broken window?" instead of "What did you see?", an interviewer might unintentionally implant the idea of a broken window into the respondent's memory. Over time, even if the witness didn't initially recall such detail, they might genuinely come to believe they saw it, thereby distorting their original memory. This interplay between leading questions and the misinformation effect can compromise the reliability of testimonies and highlights the necessity for careful, neutral phrasing in investigative contexts.

  3. Late evidence disclosure - The SUE (Strategic Use of Evidence) technique, is an approach designed to minimize the potential impact of the misinformation effect during investigative interviews. By withholding key pieces of evidence until the later stages of an interview, the SUE technique ensures that the interviewee's initial account is based purely on their recollection, uncontaminated by external evidence or suggestions. Introducing evidence later serves as a means to challenge or corroborate the interviewee's statement without leading them from the outset. This strategy helps maintain the integrity of the interview process, reducing the chances of memory distortion and ensuring that the testimonies obtained are as genuine and accurate as possible.

  4. Interviewer Opinions - During interviews, an investigator's opinion, if explicitly or implicitly conveyed, can serve as a powerful form of post-event information. The opinions and beliefs of investigators can significantly shape a person's recall of an event. If an investigator expresses a certain belief or assumption about how events unfolded, the interviewee might unconsciously adjust their testimony to align with this perspective, irrespective of their original memory. Such alterations not only compromise the integrity of the testimonial but also underscore the critical importance of maintaining neutrality and objectivity during the investigative interviewing process.

Uncontaminated corroborated statements stand as the hallmark of effective interviewing. They ensure that the information obtained is both genuine and supported by evidence, affirming the integrity and reliability of the investigative process. Science-Based Interviewing uses peer-reviewed research along with best practices to avoid interview and witness contamination. This pristine quality of testimonies, untainted by external influences, sets the gold standard for all interviews, guaranteeing that outcomes are rooted in truth and accuracy.


Conclusion


Elizabeth Loftus's work on the misinformation effect has profoundly influenced the field of psychology. It has challenged our perception of memory as a stable, reliable construct and revealed its susceptibility to alteration by external information. This research is not only scientifically fascinating but also carries practical implications, particularly in forensic and legal contexts, shaping our approach to investigative interviewing and contributing to ethical and just outcomes.


References:


References

Fisher, R. P., & Geiselman, R. E. (1992). Memory-enhancing techniques for investigative interviewing: The cognitive interview. Charles C. Thomas Publisher.

Loftus, E. F., Miller, D. G., & Burns, H. J. (1978). Semantic integration of verbal information into a visual memory. Journal of Experimental Psychology. Human Learning and Memory, 4(1), 19–31. https://doi.org/10.1037//0278-7393.4.1.19

Loftus, Elizabeth F. (2005). Planting misinformation in the human mind: a 30-year investigation of the malleability of memory. Learning & Memory (Cold Spring Harbor, N.Y.), 12(4), 361–366. https://doi.org/10.1101/lm.94705

Loftus, Elizabeth F., & Palmer, J. C. (1974). Reconstruction of automobile destruction: An example of the interaction between language and memory. Journal of Verbal Learning and Verbal Behavior, 13(5), 585–589. https://doi.org/10.1016/s0022-5371(74)80011-3

Loftus, Elizabeth F., & Pickrell, J. E. (1995). The formation of false memories. Psychiatric Annals, 25(12), 720–725. https://doi.org/10.3928/0048-5713-19951201-07

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