These days, there are few forms of evidence that are as convincing as eyewitness testimony, which may lead you to believe that eyewitness accounts are frequently accurate. Science suggests otherwise, however, which is unfortunate given just how much stock judges and juries typically place on eyewitness accounts.
According to the Association for Psychological Science, eyewitness testimony is actually far less accurate than most people assume, but many people wind up receiving convictions for their criminal charges based on eyewitness testimony nonetheless. Part of the problem may have to do with a prevailing presumption that personal memories are similar to the recordings on a video camera, which is not accurate.
Problems associated with eyewitness accounts
Contrary to popular belief, your memories do not record in your brain as they do on a video camera. Instead, eyewitness accounts are often a combination of accurate information and fictional information. They are also subject to change based on outside circumstances.
Another problem associated with eyewitness accounts is that many people mistakenly assume that those who witness criminal acts may be more prone to remember them clearly because they were especially stressful events. However, evidence suggests that people are actually less likely to accurately recall events when stressed or under duress, again calling into question the accuracy of eyewitness testimony.
Statistics surrounding eyewitness accounts
DNA evidence became an important part of forensic science in the 1980s, and many older cases underwent review once DNA testing became available. A study performed by the Innocence Project, which works to exonerate wrongly convicted people, revealed just how often inaccurate eyewitness testimony led to criminal convictions. More specifically, since 1989, 358 people facing death sentences were exonerated from crimes based on new DNA evidence. More than 70% of those people received their initial convictions because of eyewitness testimony.
In summary, eyewitness accounts are not at all as accurate or reliable as you may like to think. This is regrettable, given just how much depends on the words of eyewitnesses.