‘I Saw It With My Own Eyes’
Most scientific studies require dozens to hundreds of experiments or cases, and detailed statistical analysis, before we can accept the conclusion that event A probably caused event B. In the case of medicine and drug testing, there is typically a “control” group that doesn’t receive a given treatment, or receives a placebo instead, so that we can rule out the possible effects of the power of suggestion, and also rule out random effects. Only after such rigorous testing which can rule out the biases of the subjects and the observers, random noise, and all other uncontrolled variables, can scientists make the statement that event A probably caused event B. Even then, scientists do not speak in finalistic terms of “cause and effect” but only in probabilistic terms that “event A has a 95% probability to have caused event B.”
The same goes for eyewitness testimony, which may have some value in a court of law, but is regarded as highly suspect in most scientific studies. Thousands of studies have shown that eyewitnesses are easily fooled by distractions such as a weapon, or confused by stress, or otherwise misled into confidently “remembering” things that did not happen. This is vividly demonstrated by a startling video where the viewer is told to count the number of times players dressed in white pass the basketball. If you do it and focus on the counting, you will completely miss a man in a gorilla suit who walks right through the shot, because your attention is focused elsewhere.
As Levin and Kramer put it, “Eyewitness testimony is, at best, evidence of what the witness believes to have occurred. It may or may not tell what actually happened. The familiar problems of perception, of gauging time, speed, height, weight, of accurate identification of persons accused of crime all contribute to making honest testimony something less than completely credible.” Consequently, court systems around the world are undergoing reform as DNA evidence has shown case after case of eyewitness testimony that resulted in a wrongful conviction. One famous study involved a young woman who conclusively identified the face of her rapist and sent him to prison, only to find out later when his DNA was tested that he was not the culprit. She had seen his face on television and subconsciously associated his face with her (unseen) rapist’s face. As psychologist Elizabeth Loftus has shown, eyewitness accounts of events and their memory of them are notoriously unreliable. In her 1980 book, Memory: Surprising New Insights into How We Remember and Why We Forget, Loftus writes: “Memory is imperfect. This is because we often do not see things accurately in the first place. But even if we take in a reasonably accurate picture of some experience, it does not necessarily stay perfectly intact in memory. Another force is at work. The memory traces can actually undergo distortion. With the passage of time, with proper motivation, with the introduction of special kinds of interfering facts, the memory traces seem sometimes to change or become transformed. These distortions can be quite frightening, for they can cause us to have memories of things that never happened. Even in the most intelligent among us is memory thus malleable.”