Can you trust your memory? This neuroscientist isn’t so sure | André Fenton

• It's a really intriguing question to ponder, you know, how does time and space affect memory? And in fact, the converse, how memory affects our perceptions of time and space. The representations that we build of time and space in the brain form a framework in which we experience the world so that we can collect from the experiences, the memories that we keep.

And at the very same time, those memories that we keep, they're modifying, they're changing the very substance of that framework so that in the future, our next experiences are predicated on that modified framework. And so there's a deep interaction, a fundamental interaction between what our past experience is and how we approach the world to collect new experiences that we turn into memories.

One of the things that I feel really privileged for studying neuroscience, and in particular memory, is that I have an insight into my memory to recognize that I can't fully trust it. I will not argue on the basis of my memory for some set of events happening one way or another. And so if you now grab a bunch of people and you allow those people to have deep beliefs that their memories are knowable and true, those people will interact very differently than another set of people who actually recognize that their memories are not likely to be a good representation of what actually happened—or even what you're currently perceiving.

So in a human brain, there's just under 100 billion neurons. One neuron is better or worse able to communicate with the neuron that it's connected to or one of the 10,000 that it's connected to. And those synapses tend to strengthen when they're used repeatedly and effectively. And when they're not used repeatedly or when they're used rarely or when they're used in a mistimed manner, then those synapses tend to weaken.

And the strengthening and the weakening of those synapses is an active biochemical process that makes those adjustments. And when those adjustments persist, and when those memories persist across different classes of information and across different brain areas, cognitive psychologists knew very long ago that mindset was really crucial to how we not only perceive the world but even how we remember things from the world.

So I'll give you a concrete example: Endel Tulving proposes what he calls an When you remember something, there's actually an interaction of three crucial things: what you know, the mindset you come to try to remember from, and the cues that are used for the recollection. And so those three are fundamentally and intimately intertwined. You can't recollect one without the other in a sense.

So the fundamental fact is that when we experience the world, when we have thoughts, we are using our brains. And the brain is a self-organizing system. Through its own use, it gets modified. We're not simply reproducing what it is that we had experienced. We're reconstructing, we are building a new experience.

And we tend to build those experiences according to the stories that make sense to our minds. Even at the level of perception, we can all experience what would appear to be the same thing. For example, look out the window or look down the street. Everyone will focus their attention on different aspects of what's available for them to recollect.

And so naturally, we even have a different recording of the actual events. Then when we retell these stories and recount them, we reconstruct those events from what we remember from the fragments of our memory and we build stories around our mindset—and the stories are triggered by, of course, the cues that we're using to retell those stories.

So at the end of the day, many of us and many of the things that we engage in seek to come to an understanding of what I would call "truth," something that we can all agree on and recognize as being meaningful and honest and universal. And so how do you accomplish that?

Well, by recognizing that we all have access to that truth, that we all have a distorted perception and we will have later a distorted understanding and recollection of the perception called memory. And if you fundamentally believe that, it demands that you act in the world with a certain sense of humility and empathy for others.

If you are open to listening, if you're open to self-correction, and of course, you should be because you know that you can't know. So when new evidence appears, when a new point of view appears, by being ready to consider it, by being mindful of what is available to understand, we have a chance at least to converge not on what I think is right or what you think is right, but what actually might be true.