Eyewitness Identifications and the Science Behind Remembering

Catherine Tran
Thomas Jefferson High School for Science and Technology

This article was the 2nd place winner in the 9th-10th grade division of the Teknos 2020 Summer Writing Competition.

An investigator places six photographs in front of a murder witness and asks him to identify the crime suspect. Anxious and worried, the witness struggles to recall the face of the perpetrator and match it with one of the images. What color was the murderer’s hair? Was he wearing glasses? Did he have any facial hair? Finally, after much thought and consideration, the witness points to one photo—a picture of the suspected murderer. The suspect is soon brought into the interview room, and after getting a good look at the suspect, the witness becomes more confident in his decision. “That’s him,” he declares, “I saw this man at the crime scene right when the murder took place. I’m absolutely sure he is the murderer.”  

The suspect claims he is innocent, but his pleas are ignored. With all evidence pointing against him, the suspect is tried, convicted, and sent to prison. Years later, DNA evidence reveals that the suspect was telling the truth—he truly was innocent! Authorities exonerate him and apologize for the mistake, but it is too late. The damage has already been done.

You are likely familiar with eyewitness identifications. A person who was present at the scene of a crime is asked to identify a suspect from a photo spread, helping authorities locate and arrest criminals. Despite their frequent use, eyewitness identifications can be unreliable. The Innocence Project, a nonprofit organization working to clear the names of wrongly convicted prisoners, reports that 71% of more than 360 exonerated prisoners in the U.S. have been falsely accused due to witness misidentification [4]. Unfortunately, thousands of others could potentially be serving time in prison due to the same issue.

Eyewitness identifications are often inaccurate due to their heavy dependence on memory recognition and recollection. Witnesses must use their memory to recall a crime and its associated details, including the identity of the responsible criminal. When a witness forgets important details or remembers false information, problems arise, and he or she may end up accusing an innocent person of a crime they did not commit. 

To understand memory’s role in eyewitness identifications, we should study how the human memory functions. Memory is a complex system involving the formation, storage, and retrieval of information. The process of creating memories usually begins in the temporal lobe when we perceive sensory cues (see Figure 1) [6]. Imagine sitting outside your favorite bakery, sipping a cup of coffee while listening to relaxing music. Different cues, such as the soft piano melodies or the sweet aroma of freshly-baked pastries, are registered into the brain at the cortex’s sensory areas through acoustic, visual, tactile, or semantic encoding [6]. Neurons send electrical pulses between synapses in the hippocampus, a part of the medial temporal lobe that is involved in the creation and storage of long-term memories [11]. The pulses release neurotransmitters, forming neural connections that can develop into a network to create a memory trace, or an engram [6, 8, 15]. Once a memory is encoded, it remains in the prefrontal cortex as a short-term memory, momentary memories that are possessed for short periods [11]. By constantly revisiting a particular memory, we become more familiarized with the information in the memory. Synaptic plasticity is what allows the memory’s neural connections to change their strength, determining how well a memory is retained [8, 10].

Short-term memories are converted into long-term memories via memory consolidation in the hippocampus, and the sensory elements making up a long-term memory (sights, sounds, tastes, etc.) are stored in various locations throughout the cortex [11, 12]. To remember and recall information, we use memory retrieval to reactivate a certain engram, which reconstructs the long-term memory and moves it back to our short-term memory in the hippocampus [7]. During this stage, we tend to forget information due to our brain’s inability to retrieve decayed or interrupted memories [8].

Several types of memories are stored across different regions of the brain, enabling us to carry out certain tasks, recall events, and retain information (see Figure 2). There are two main types of long-term memories: procedural (implicit) memories, used to perform motor skills, and declarative (explicit) memories, used for consciously recalling factual knowledge and personal experiences. In eyewitness identifications, witnesses mostly rely on recognition memory, a type of declarative memory that allows us to recognize people based on their faces [13].

Studies show that multiple regions of the brain, particularly a region of the temporal lobe called the fusiform gyrus, play roles in facial perception and recognition (see Figure 3). The fusiform face area, located within the fusiform gyrus, has been shown to display high levels of neuron activity when a person is viewing faces [16]. When we encounter somebody, we are overcome with a feeling of familiarity as our brain tries to recall memories associated with that person’s face [13]. Scientists are in the middle of studying how exactly our brain recognizes people, and there is still much to learn about this fascinating concept.

What happens when a memory is distorted? Oftentimes, retrieved memories are altered, portraying events differently from how they actually happened. Memory retrieval involves reconstructing memories from a number of elements, and different factors can interfere with this process, changing how a memory is perceived [6]. Details might be excluded or added in, sometimes due to influence from others’ suggestions. A person may forget certain information, or they may combine details from different experiences into one memory [6]. There is a wide variety of ways that our memories can be altered and used to deceive us.

 The idea of memory distortion was proven in a famous study conducted by Dr. Elizabeth Loftus, a psychologist who has done much research on the human memory and its function [5]. Multiple subjects were asked questions about a simulated car crash that was viewed beforehand. These questions used different verbs, like “smash'' or “bump”, to describe the crash. When asked about the cars’ speeds, subjects gave varying responses depending on how the questions were worded. Those who were asked questions with stronger word choices said the cars were traveling at very high speeds, while subjects who were asked questions with weaker word choices gave lower speeds as their answer. Loftus’s experiment displays how memories can be changed, and it gives us an idea about the consequences of memory distortion. Forgetting memories or remembering false memories can develop beliefs and biases, posing a major problem to witness identifications. A witness’s memories are a critical component for identifying crime suspects, so these memories should be correct to ensure an accurate eyewitness identification.

Because memory plays a huge role in criminal lineups, scientists are trying to incorporate memory sciences into these practices in an attempt to reform eyewitness identifications. Normally, authorities use sequential (SEQ) and simultaneous (SIM) lineups to conduct witness identifications. SEQ lineups present a witness with one suspect photo at a time, and SIM lineups display an entire photo spread at once [9]. The configuration of these lineups makes witnesses more prone to uncertainty, and the administrator can only know so much about a certain lineup [3]. Researchers at the Salk Institute for Biological Studies recently developed paired comparisons (PAR) lineups, an alternative lineup procedure that displays images in a photo spread multiple times among random pairings. Unlike traditional methods, PAR lineups provide administrators with information about the fairness of a lineup and the strength of a witness’s memory [3]. PAR lineups acknowledge memory, bias, and other factors, making them more reliable and accurate than traditional criminal lineups. These PAR lineups are just one of the numerous efforts being made today to improve witness identifications.

Memories are a critical aspect of our daily lives, and they are needed in a wide variety of situations, including witness identifications. In any case, human memory is a very delicate topic; one wrong remembrance or a weak retrieval not only can decide one’s fate in the criminal justice system, but can also ultimately impact other cornerstones to your life. Our memories can have huge consequences, and it is important to recognize how much they can impact our lives.

References

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