Why Humans Make Unreliable Eyewitnesses

Many trial lawyers use eyewitness testimony in court to prove or disprove evidence.  Eyewitness testimony is one of the most unreliable pieces of evidence which can be presented yet many jurors still give the most credit to an eyewitness statement, assuming the witness is trustworthy.

Many people who witness an event do not want to get involved.  However, for those who do, their account of an event can be skewed by telling what they think they saw instead of what actually happened.  Some accounts can be unintentionally swayed by the person asking the questions.  For example:  A person can ask, "How fast was the car going?"    By using the term "fast" the witness may think you mean "speeding" and produce a higher number.  However, by asking "what was the car doing just before they hit?" would produce a number closer to the truth.

According to a report in the St. Petersburg Times,  "Those who study memory are becoming increasing unwilling to trust it." Researcher Henry Roediger, at the American Psychological Association, said that experiments with college students at Rice University in Houston indicate that it's quite easy to introduce false memories. "People confidently remember events that never happened to them," he said.

Still quoting from the St. Petersburg Times article, "When Roediger showed subjects a film and then later a written version of the same story with minor changes, they failed to notice the discrepancies. Later, when asked what they'd seen on film, they reported the version they'd read and not what they saw."

Another example of bad eye-witnesses is the concept of "Inattention Blindness".  Inattention blindness is the idea that people often miss large changes in their visual field.  This has been demonstrated in many experiments.

Watch the video below and count how many times the white team passes the basketball.


You should have counted 13 passes.  However, did you notice the dancing bear?  The dancing bear is clearly in our line of vision but most people do not notice it.

Now watch the experiment in the video below.  The video demonstrates a phenomenon called "Change Blindness."  


"Change Blindness" demonstrates the human capacity to encode, retain and compare information from one glance to the next.  This video clearly shows that our awareness of our visual surroundings is far more sparse than most people intuitively believe.

Another  study shows that 'flashbulb memories', memories from traumatic or dramatic events, are very strong and remembered vividly.   For example:  Most people can remember where they were and what they were doing when they first heard about the September 11, 2011 attacks.  Chances are they can tell you in great detail the memory of that day.  But research clearly shows most people would be wrong about the majority of their memory.  In 1986, Ulric Neisser, a psychological researcher who studied 'flashbulb memories', took the opportunity the day after the Challenger explosion to asked his students to write down what happened, where they were, what they were wearing, the TV coverage, etc.  Three years later he asked the same students to write down their memory of that day's events again.  Over 90% of the 3-year later reports were different.  Over half of the recollections were inaccurate in 2/3 of the details. One person, when shown her first description written three years earlier said, “I know that’s my handwriting, but I couldn’t possibly have written that”.  All of the students who participated in the research were confident that their latter accounts were completely accurate.  Similar research has been conducted on the 9/11 memories, with similar results.  

It is interesting that Dr. Neisser himself found that he was a victim of false memories. For years, he had said that he was listening to a baseball game on the radio when he heard about the attack on Pearl Harbor on Dec. 7, 1941. Finally, he said, it dawned on him that he could not have been listening to a baseball game in December.

Each year as many as 80,000 eyewitnesses make identifications or provide a statement during an investigation. We would like to think that these eyewitnesses are all getting it right, but clearly the research has shown time and again that people are prone to false memories.  We will never know how many people have been wrongly convicted due to false memories of an eyewitness.  As long as eyewitness testimony is given a lot of weight, there will continue to be countless wrongful convictions in our court system.

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