Your Vivid, Clear, and Wrong Memories
We give our memories too much credit. When it comes to emotionally charged moments, we often recall them with vivid and presumably precise detail, but it turns out that any details not central to the event itself may very well be inaccurate.
Imagine a surprise birthday party that delights you to no end. Everything was amazing, the cake was perfect, and all your close friends were there. That initial moment of surprise triggered a series of interactions in your brain— your visual cortex has a direct pipeline of information to your amygdala, the portion of your brain that controls your emotional responses. The amygdala takes in that visual information about the party, and spurs the hippocampus, the small region that helps encode memories, to really pay attention because something important is happening, and it needs to be remembered.
This is fine for the core of the memory— the party was a big, happy surprise. But it turns out that even though all three regions of the brain are working hard to learn about the situation, your brain is really only accurately recording the core event. Other details are being recorded as being vivid and impressive, but what those details actually are… well, your brain might fill those in later. So while you may be able to clearly picture the colors of the balloons at the party, they may not have been there at all. They may have been retroactively added, but because you know it was an important event, you believe all the details your brain serves up.
The retroactive aspect of this isn’t just a way to make you crazy. In some dire scenarios it can make a bit more sense why this mechanism would have developed. Imagine a dog biting you on Friday. That vivid moment is important, as your brain really wants to help you not get bitten again. So it then pulls in memories about that dog from Thursday, Tuesday, and Monday and compiles them, helping you have a more complete reference to what happened, and how to have more positive outcomes in the future. The big catch is when you’re aware of changes in your memory’s chronology. Most of the time we just trust that those clear images of the dogs eyes, teeth, etc. in our mind’s eye are sharp and reliable, even if the day we were bitten we didn’t actually see the bite take place by the time we felt it.
Source: You Have No Idea What Happened by Maria Konnikova, The New Yorker