I took the above pictures last night at my regular TRAX train stop. At the station, I talked to a number of people who were on the train when the truck and the train collided. These eyewitnesses all said pretty much the same thing: the guy in the red truck ran a red light and got hit by the train; the truck spun around and smashed into the concrete; and the train driver slammed on the breaks.
That sounded like a convincing eyewitness description of what happened until I dug a bit deeper. Everyone I talked to, when I asked if they saw the accident as it happened or if they only felt it, said that they only felt the accident. One guy said he was reading when it happened and just felt the train slam on its brakes. And from personal experience, I can’t see the traffic lights when I’m sitting on the train. How did everyone come to the conclusion that the truck ran a red light?
There’s two possible explanations for this consensus of what happened, despite few having actually watched it. 1) Everyone was passing along information they got from one of the few people who actually witnessed it. 2) Everyone was doing a lot of “gap filling” in their knowledge of what happened. They took what they knew to be facts and made assumptions about what happened. These two explanation are not mutually exclusive and actually reinforce one another. The gaps in our knowledge are most easily filled through information from other people. But it’s entirely possible that no passengers saw the truck run the red light and everyone is relying on gap filling, and groupthink was convincing each person of the correctness of this narrative.
Most of the time, there’s nothing wrong with gap filling or using second-hand information; such mental processes help us function. Unfortunately, people are very poor about remembering where they actually acquired a piece of information. Once our brains come to accept something as fact, we completely forget that we didn’t actually see the train colliding with the car. Instead, we remember the event around the narratives we have each formed in our heads. Also, memory is affected by retelling, but we rarely tell a story in a neutral fashion. People add emotion and subtle details to the narrative to help it arrive at a conclusion.
This can be a big problem for lawyers who need to question witnesses weeks or even years after an event. Witnesses will tell the juries that they saw the truck run the red light, when they really didn’t, and they are not necessarily being untruthful when they do that. They really think they saw the accident the way they recount.
There isn’t an easy solution to the memory problem. The more we learn about memory, the more we learn how fallible it is. Eyewitness testimony has an appropriate place in our court system, but that testimony should be buttressed with scientific evidence.