Understand & Improve Memory Using Science-Based Tools | Huberman Lab Essentials
In a Nutshell
Memory forms through selective perception and is enhanced by **repetition**, **adrenaline spikes immediately after learning** (via cold exposure, exercise, or caffeine for one-trial consolidation, as shown in McGaugh/Cahill studies), and **zone 2 cardio** (180-200 min/week) releasing osteocalcin to boost hippocampal neurogenesis and function. Additional tools include **mental photographic snapshots** for visual recall, **13-min daily meditation** for attention/memory gains (Suzuki study), and prioritizing calm focus during learning followed by post-learning arousal. Adrenaline acts as the final common pathway stamping experiences into long-term memory, explaining phenomena like deja vu and historical stress rituals.
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Welcome to Huberman Lab Essentials, where we revisit past episodes for the most potent and actionable science-based tools for mental health, physical health, and performance. Andrew Huberman is a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today discussing memory, in particular, how to improve your memory. We are constantly bombarded with physical stimuli: patterns of touch on our skin, light to our eyes and skin, smells, tastes, and sound waves. Each and all of those sensory stimuli are converted into electricity and chemical signals by the nervous system: brain, spinal cord, and their connections with the organs of the body and back to the brain and spinal cord. For instance, if you can hear this speaking right now, you are perceiving the voice, but most likely neglecting the feeling of contact of your skin with whichever surface you are 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 be overwhelmed with all the things happening in any one given moment.
Memory is simply a bias in which perceptions will be replayed again in the future. This raises the question: why do we remember certain things and not others? As you go through life, you are constantly bombarded with sensory stimuli. Some of those you perceive, and only some of those perceptions get stamped down as memories.
Today teaching how certain things get stamped down as memories and how to leverage that process to remember the information you want far better.
Each individual thing that we remember or want to remember is linked to something by either a close, medium, or very distant association. This is immensely important. Many encounter programs designed to enhance memory, like phenomena who can remember 50 names in a room full of people or names of novel objects or in different languages. Often done by association: linking the sound or meaning of a word in a way meaningful to them to enhance memory. That can be done and is impressive. For those who can do that, congratulations. Most cannot, or it requires a lot of effort and training.
However, there are things that leverage the natural biology of our nervous system to enhance learning and memory of particular perceptions and information.
One tool that absolutely works is repetition. The more often you perform or recite something, the more likely you are to remember it in the future. At the neural level, repetition encourages the firing of particular chains of neurons in a particular circuit: neuron A, B, C, D in that sequence over and over, strengthening those nerve connections.
The problem is most people lack patience, time, or have deadlines. They want to remember things better in general or more quickly. There is a way to accelerate repetition-based learning, shifting the curve so you establish stronger connections more quickly: from 1000 repetitions down to fewer or even once.
James McGaugh and Larry Cahill did experiments over decades establishing what's required to remember things quickly. They evaluated stress and particular neurochemicals associated with stress to improve ability to learn information, not just emotional but all kinds.
In animal models: put a rat or mouse in an arena where at one location it receives an electrical shock. Next day, remove shock device; animal avoids that location (conditioned place aversion). Occurs in one trial (one-trial learning), hippocampus-dependent. Depends on epinephrine (adrenaline) and to some extent cortisol. If block epinephrine pharmacologically (released but cannot bind receptors), animal treads back into shocked area, as if it didn't remember.
Opposite is true for conditioned place preference: put animal in arena, reward with food, warmth, or mating opportunity at one location. Next day, returns to that location. Works for male rats/mice (mate anytime) or receptive female. Explains why people return to same bar seat or restaurant. Depends on adrenaline release.
Not just stress, but heightened emotional state in brain and body allows one-trial learning for positive and negative events.
True for humans: McGaugh and Cahill gave people a boring paragraph to read. One group read it then placed arm in ice water (up to shoulder), evoking significant adrenaline release (measured). Information retained as well as emotionally intense information, despite being boring. Effect blocked if block adrenaline function.
Presence of high adrenaline, norepinephrine, and epinephrine stamps down memory quickly, strengthening neural connections with just one activation. Removes need for repetition.
Tools must account for identity of neurochemicals (adrenaline, etc.) and timing of their release.
Common approach: drink caffeine (coffee, yerba mate), focus hard, eliminate distractions. Or use pharmacology like alpha-GPC or phosphatidylserine before learning cognitive info or physical skill. Results pointed to adrenaline release after learning enhancing it. But caffeine/alpha-GPC increase epinephrine/adrenaline/dopamine over time, so taking before/during seems logical.
Not optimal. Best window: immediately after or 5-10-15 minutes after repeating/trying to learn (cognitive or physical skill). Spits in face of common practice of taking stimulants before/during.
Reason: ingestion (drink/capsule) takes time to absorb into bloodstream and reach brain. Varies by substance, food in gut, etc. Hundreds of studies in animals/humans show triggering adrenaline increase late in or immediately after learning most beneficial to retain info long-term and reduce repetitions.
Non-sleep deep rest, naps, and sleep still vital: strengthening/neuroplasticity occurs during deep sleep and non-sleep deep rest. Two papers in Cell Reports (Cell Press): brief naps (20-90 minutes) some hours after learning enhance rate even 1-4 hours later. Actual reconfiguration happens in naps/deep sleep.
No need to nap/sleep immediately after learning. Optimal protocol:
- Focus intensely on learning.
- Get excellent sleep (fundamental for health/performance/learning/memory).
- Nap (10-90 min) if doesn't interrupt nighttime sleep, or non-sleep deep rest.
- Spike adrenaline safely at tail end or immediately after learning bout (compatible with above).
Immediately after learning: heightened state of emotionality/alertness.
No need for pharmacology unless already using safely. Avoid if not used to caffeine (e.g., four espressos causes anxiety/panic). Alternatives:
- Cold shower, ice bath, cold circulating bath (evokes epinephrine/dopamine).
- Hard run.
- Anything increasing adrenaline reduces repetitions needed.
Caution: don't chronically push (e.g., alpha-GPC + double espresso during/after). Not absolute adrenaline amount that matters, but delta (relative to 1-2 hours prior). Modestly low baseline for focus, then spike after.
Acute stress enhances learning/immune; chronic stress (elevated epinephrine/cortisol) inhibits learning/memory/immune (work of Bruce McEwen, Rockefeller; Robert Sapolsky).
Leverage: calm yet alert high attentional state for focus (vital for encoding/neuroplasticity), remain calm, then spike adrenaline after.
Beautiful review in Neuron (Cell Press): "Mechanisms of Memory Under Stress." Opening: > "In medieval times, communities threw young children in the river when they wanted them to remember important events. They believe that throwing a child in the water after witnessing historic proceedings would leave a lifelong memory for the events in the child."
Practice understood spiking adrenaline after event enhances memory. Counterintuitive: kid remembers preceding events too.
Other potent tool: exercise. Numerous studies in animals/humans (e.g., Wendy Suzuki, NYU). Learning/memory involves strengthening synapses/circuits, except cardiovascular exercise increases dentate gyrus neurogenesis (new neurons in hippocampus subregion for learning/memory).
Minimum 180-200 minutes zone 2 cardiovascular exercise weekly (steady state). Indirectly via cardiovascular fitness improvements (blood/lymphatic flow).
Debate on adult human neurogenesis, but clear benefits for health.
Exercise impacts via hormones from bone (endocrine effects) like osteocalcin traveling to brain, enhancing hippocampus function. Findings from various labs, one important lab
Laboratory of Eric Kandel at Columbia Medical School studied effects of exercise on hippocampal function and memory. Cardiovascular exercise creates release of osteocalcin from bones that travels to brain and sub-regions of hippocampus, encouraging electrical activity, formation, and maintenance of connections within hippocampus to lay down new memories.
Much of brain real estate devoted to movement. Relationship between brain and body for maintenance and improvement of neural circuitry depends on body movements and signals from body that brain is still moving.
Osteocalcin released from bone in response to load-bearing exercise: running, weightlifting (not tested directly but imagined), jumping and landing, body weight movements. Big bones like femur release more osteocalcin than movements of digits.
Body constantly signaling to brain about status of body and varying needs of brain to update circuitry. Fits biology of exercise, osteocalcin, and hippocampal function.
Exercise alone not sufficient to keep neural architecture healthy, young, and able to learn. Must engage in attempts to learn new material: physical (new movements, skills) or cognitive (languages, mathematics, history, current events).
Physical movement, cognitive ability, potential to enhance cognitive ability, and learning new physical skills intimately connected. Osteocalcin one way brain-body relationship established and maintained.
Study: "Photographic Memory: The Effects of Volitional Photo Taking on Memory for Visual and Auditory Aspects of an Experience." Refers to use of camera photographs or mental camera photographs (looking and blinking to snap mental snapshot).
Example: Two years ago in Uber in New York, took mental snapshot of city street scene (guy in yellow shirt walking, construction). Still recalls image because of mental snapshot.
Study hypothesis: Choosing what to photo-take enhances memory for objects, places, people, details. Findings confirm this.
To remember something or somebody: Take photo, pay attention while taking it (doesn't matter if look at photo again). Framing photograph stamps down robust visual image in mind, better than just looking.
Possible reason: Framing small aperture of visual scene (not tested). Much learning is visual; decision to take mental snapshot (blink eyelids) stamps down visual memory like camera does.
Work of Susumu Tonegawa at MIT and Mark Mayford at Scripps Institute and UC San Diego. Evaluated neural firing patterns in hippocampus as subjects learn new things: Neuron A fires, then B, then C in sequence (like piano keys to song/memory).
Used molecular tools to label/capture neurons, later activate in same sequence, different sequence, or all at once. All evoked same behavior and memory.
At neural circuit level, this is deja vu. Explains feeling of familiarity (e.g., "I've been here before," "I know you") without specifics. Most mechanistic explanation for deja vu.
Study by Wendy Suzuki at NYU: "Brief Daily Meditation Enhances Attention, Memory, Mood, and Emotional Regulation in Non-Experienced Meditators." Subjects 18-45, no prior experience.
One group: 13-minute meditation (body scan for tension/relaxation, focus on breathing, return attention).
Control: Listened to podcast 13 minutes, no body scan or breathing focus.
Daily for 8 weeks. Effects: Enhances attention, learning, memory (not seen at 4 weeks).
Must continue meditation. 13 minutes/day not big commitment.
Speaker adopting 15 minutes/day meditation for cognitive improvements (previously 3-5 or 10 minutes).
Any neurochemicals can increase adrenaline (epinephrine) in brain/body. Adrenaline final common pathway stamping experiences/perceptions into memory.
Answers why remember some events not others despite constant sensory experiences: epinephrine/adrenaline (with other chemicals) way particular events remembered.
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