While our emotions lie outside the scope of this work (it is already recognized we can suffer from all kinds of emotional diseases and there is no need to deal with that here), there is another function that we traditionally believe our brains perform well. That function is remembering. People tend to think of their memories as stored boxes they can consult at a later date, providing accurate descriptions of the facts we experienced in our own lives. It might be hard to find a specific memory sometimes and we do worry about forgetting, from simple information we can no longer recall to more serious pathologies where a patient memories can slowly be lost in a permanent way. All this fits well with the information in boxes metaphor, as one can eventually lose those boxes never to find them again. Or lose them for a while, until some new circumstances bring them back to our attention.
Most people, however, do not doubt the contents of their memory. If they do have a memory, unless they suffer from some delusional state, that means they believe things happened exactly they remember. And we trust our memories so completely that we send people to jail every day based only on witness testimonies, that is, on what people remember they saw or heard. And while a lawyer can defend a client by claiming the conditions of the perception of the witness were not good enough, no problem is usually detected on the ability to remember. That is, the legal system understand our perceptions can be flawed and should not be trusted, under the right circumstances. But it assumes that a healthy person will not create false memories or somehow alter the original ones.
This assumption tends to be considered true not just by the layman but also, until recently, by many psychologists. And, as a matter of fact, many practitioners believed (some still do) in the concept of "repressed memory''. That is, an event that a person has experienced in the past and have not really forgotten about. Instead, just the conscious memory is missing, as that event would probably have been very traumatic. Many therapists worked based on the idea that these memories can be recovered through treatment. And that, when these memories are indeed "recovered'', they correspond to actual events in the life of the patient.
The first indication that there was something wrong with this picture came from the unexpectedly large number of cases observed in the 90s where people claimed to have recovered "repressed memories'' of abuses they had suffered. What was particularly suspicious was the fact that the stories those people told often include elements that were supposed to be rare, as, for example, satanic practices. All those cases were recovered under particular types of psychotherapy and, as it should be if those memories were real, arrests and convictions did happen as consequence. The strange number of these cases did make a number of researchers worried that those memories, as vivid and real as they seemed to be to those who had recovered them, might actually be an artifact of the therapy.
Research followed, as it should. In a series of very interesting experiments, Elizabeth Loftus observed she could indeed create false memories in the mind of her subjects. Cases of people who had been wrongly found guilty were later observed, not only related to ``repressed memories'', but also in many cases where the evidence of guilt consisted of witness reports. Simple things like showing pictures of innocent people to a victim could cause that same victim to recognize, later, a man in those pictures as the man who had raped her. It is not clear how many innocent lives were destroyed due to our lack of understanding of how our minds work. Or how many real culprits were not identified by the same problem (for an explanation of the main results of this line of research, there is a very interesting TED lecture).
The image that emerged from those experiments is a different one when compared with previous beliefs. Our memory seems to be much more fluid than any of us would have thought. It is not just that we can suffer from problems with perception. As we learn more about some event, our brains actually change the very recording of that event, so that it will fit with our new beliefs. Missing pieces of information can be obtained from sources as unrelated to the event as a picture one observes later. What we carry in our minds is actually a mixture of what we observed, what we expected to see and things we have experienced or thought later, all mixed ("Memory - like liberty - is a fragile thing'', Elizabeth Loftus}.
In order to finish the topic of our memory, there is an interesting phrase by Steven Novella that he published while discussing the problem of the reliability of our memories in his blog:
"When someone looks at me and earnestly says, "I know what I saw,'' I am fond of replying, "No you don't.'' You have a distorted and constructed memory of a distorted and constructed perception, both of which are subservient to whatever narrative your brain is operating under." Extracted from here.
