Understand & Improve Memory Using Science-Based Tools | Huberman Lab Essentials

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Welcome to Huberman Lab Essentials, [music] where we revisit past episodes for the most potent and actionable science-based tools for mental health, physical health, and performance. I’m Andrew Huberman and I’m a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today we are discussing memory, in particular how to improve your memory. We are constantly being bombarded with physical stimuli, patterns of touch on our skin, light to our eyes, light to our skin for that matter, smells, tastes, and sound waves. Each one of and all of those sensory stimuli are converted into electricity and chemical signals by your so-called nervous system, your brain, your spinal cord, and all their connections with the organs of the body and all the connections of your organs of the body back to your brain and spinal cord.

For instance, if you can hear me speaking right now, you are perceiving my voice, but you are also most likely neglecting the feeling of the contact of your skin with whichever surface you happen to be sitting or standing on. It is only by perceiving a subset, a small fraction of the sensory events in our environment, that we can make sense of the world around us. Otherwise, we would just be overwhelmed with all the things that are happening in any one given moment. Now, memory is simply a bias in which perceptions will be replayed again in the future. Now, this might seem immensely simple, but it raises this really interesting question, which we talked about before, which is why do we remember certain things and not others?

Because according to what I’ve just said, as you go through life, you’re experiencing things all the time. You’re constantly being bombarded with sensory stimuli. Some of those sensory stimuli you perceive, and only some of those perceptions get stamped down as memories. Today I’m going to teach you how certain things get stamped down as memories, and I’m going to teach you how to leverage that process in order to remember the information that you want far better. Each individual thing that we remember or that we want to remember is linked to something by either a close, a medium, or a very distant association.

This turns out to be immensely important. I know many of you will read or will encounter programs that are designed to help you enhance your memory. You know, that you have these uh phenoms that can remember 50 names in a in a room full of people where they can remember a bunch of names of novel objects or maybe even in different languages. And often times that’s done by association. So, people will come up with little mental tricks to, you know, either link the sound of a word or the meaning of a word in some way that’s meaningful for them and will enhance their memory.

That can be done and is impressive when we see it. And for those of you who can do that, congratulations. Most of us can’t do that or at least it requires a lot of effort and training. However, there are things that we can do that leverage the natural biology of our nervous system to enhance learning and memory of particular perceptions and particular information. So, let’s talk about tools for enhancing memory.

Now, there’s one tool that is absolutely clear works. And that’s repetition. The more often that you perform something or that you recite something, the more likely you are to remember it in the future. And while that might seem obvious, it’s worth thinking about what’s happening when you repeat something. But when I say what’s happening, I mean at the neural level.

What’s happening is that you are encouraging the firing of particular chains of neurons that reside in a particular circuit, right? So, a particular sequence of neurons playing neuron A, B, C, D played in that particular sequence over and over and over again. And with more repetitions, you get more strengthening of those nerve connections. The problem for most people is that they either don’t have the patience, they don’t have the time, and sometimes they literally don’t have the time because they’ve got a deadline on something that they’re trying to remember and learn. Or they simply would like to be able to remember things better in general and remember them more quickly.

This process of accelerating repetition-based learning so that your learning curve doesn’t go from having to perform something a thousand times and then gradually over time it’s a thousand, 750 times a day, 500 times a day, 300 times a day and down to no repetitions, right? You can just perform that thing the first time and every time. Well, there is a way to shift that curve so that you can essentially establish stronger connections between the neurons that are involved in generating that memory or behavior more quickly. How do you do that? Well, in order to answer that we have to look at the beautiful work of James McGaugh and Larry Cahill.

James McGaugh and Larry Cahill did a number of experiments over several decades really that really established what’s required to get better at remembering things and to do so very quickly. They evaluated the capacity for stress and for particular neurochemicals associated with stress to improve our ability to learn information, not just information that is emotional but information of all kinds. So, I’m going to describe some experiments done in animal models just very briefly and then experiments done on human subjects. If you take a rat or a mouse and put it in an arena where at one location the animal receives an electrical shock and then you come back the next day, you remove the shock-evoking device and you let the animal move around that arena. That animal will quite understandably avoid the location where it was shocked, so-called conditioned place aversion.

That effect of avoiding that particular location occurs in one trial. That’s a good example of one trial learning. So, somehow the animal knows that it was shocked at that location. It remembers that. It is a hippocampal-dependent learning.

They remember it after the first time and every time unless you are to block the release of certain chemicals in the brain and body and then chemicals I’m referring to are epinephrine, adrenaline, and to some extent cortisol. Now, we know that the effect of getting one-trial learning somehow involves epinephrine at least in this particular experimental scenario because if researchers do the exact same experiment and they have done the exact same experiment, but they introduce a pharmacological blocker of epinephrine so that epinephrine is released in response to the shock, but it cannot actually bind to its receptors and have all of its biological effects well, then the animal is perfectly happy to tread back into the area where it received the shock. It’s almost as if it didn’t know or we have to assume it didn’t remember that it received the shock at that location. So, it all seems pretty obvious when you hear it. Something bad happens in a location, you don’t go back to that location.

But, it turns out that the opposite is also true, meaning for something called conditioned place preference, you can take an animal, put it into an arena, feed it or reward it somehow at one location, take the animal out, come back the next day, no food is introduced, but it’ll go back to the location where it received the food, or you can do any variant of this. You can make the arena a little bit chilly and provide warmth at that location, or you can take a male animal, it turns out male rats and mice will mate at any point, or a female animal that’s at the particular so-called receptive phase of her mating cycle, and give them an opportunity to mate at a given location, they’ll go back to that location and wait and wait. This is perhaps why people go back to the same bar or the bar seat at the bar or the same