How to Improve Your Memory & Cognitive Function at Any Age | Dr. Alan Castel

2026-07-13 - 148 min - source - Read full transcript

Andrew Huberman (host)Dr. Alan Castel

Key insights

Repeated exposure to something does not mean you remember it well; retrieval effort and productive failure build stronger memories than passive repetition.

Castel's classic demonstration: people who have seen the Apple logo thousands of times still cannot correctly recall whether the bite is on the left or right, or if there is a leaf. Having people draw the logo from memory first, then compare it to the real thing, produces better learning than simply looking at it again, because the failed retrieval attempt highlights exactly what wasn't known.

desirable-difficulty-learning

Memory is reconstructive, not a recording, and eyewitness identification can permanently overwrite what someone actually saw.

Castel describes the Ronald Cotton case: a survivor who deliberately tried to memorize her attacker's face during the assault nonetheless misidentified an innocent man in a lineup. Once she identified him, her memory of the actual attacker's face was replaced by her memory of the person she had identified, and DNA evidence exonerated him only decades later.

memory-formation

Consciously deciding to mentally 'take a photo' of a moment can improve memory of it, but relying on an actual camera can sometimes weaken memory instead.

Huberman describes deliberately deciding to remember a scene (a picnic, a street corner) without a camera and still recalling it years later. Castel says research on this selection process is mixed: the act of choosing 'this is a special moment' aids encoding, but offloading the experience to a photo because 'I don't need to remember it' can reduce how well the brain encodes the moment.

memory-formation

Brisk walking three to four times a week measurably grows the hippocampus and improves memory within a year, offsetting the roughly 1-2% annual volume loss that begins around age 50.

Castel cites a randomized study comparing a walking group (30-40 minutes, 3-4x/week) to a stretching-only control group. The walking group's hippocampus increased in volume by about 1% and their memory was measurably better a year later, despite the exercise not being especially intense. Mechanism is unclear but likely involves better sleep and oxygen delivery to the brain.

successful-aging

Balance is an underrated marker of healthy aging and is trainable within weeks, unlike many other age-related declines.

One in four adults over 65 will experience a fall, which often triggers a downward spiral (reduced mobility, reduced exercise, hippocampal shrinkage). Most people overestimate their balance because they haven't fallen yet. A simple test (stand on one leg for 10 seconds, then with eyes closed) reveals the deficit, and balance training via yoga, Tai Chi, or single-leg stands can improve it considerably in a month or two.

balance-and-fall-prevention

How old you feel (subjective age) predicts how long you'll live better than your chronological age does.

After age 40, most people report feeling about 20% younger than their actual age. Castel says this subjective age measure is a better longevity predictor than biological age, suggesting that self-perception and agency around aging carry real physiological weight, not just psychological comfort.

successful-aging

Curiosity about specific topics you already care about tends to increase with age, even as general trait curiosity declines, and appears to protect memory for that material.

Castel's lab distinguishes 'trait curiosity' (a general disposition to be curious, which declines with age) from 'state curiosity' (interest sparked by a specific piece of information), which increases with age when the topic already matters to someone. This selective curiosity may explain why older adults can maintain sharp memory in narrow domains they care about while forgetting information that doesn't fit their existing interests or schemas.

memory-formation

Castel's ABCs framework distills successful aging into Attitude/Adapt, Balance, and Connection, based partly on an interview with UCLA coach John Wooden.

Wooden told Castel the two most important words in life were love and balance. Castel expanded this into attitude (a positive, agentic view of what's possible with age correlates with longer life and lower dementia risk), adapt (resilience through physical and mental change), balance (both physical fall-prevention and life balance, illustrated by Wooden's own fatal reluctance to press his life-alert button out of pride), and connection (fewer but higher-quality relationships matter more as social circles shrink with age).

successful-aging

Shortening someone's perceived time horizon shifts their priorities toward emotionally meaningful goals, independent of their actual age.

Citing Stanford psychologist Laura Carstensen's socio-emotional selectivity theory, Castel notes that when younger people are told (in study conditions) they have only five to ten years left to live, they make choices resembling older adults: prioritizing meaningful relationships and experiences over abstract future goals. This suggests the shift isn't really about age but about perceived time remaining.

purpose-and-connection

Older adults showed more resilience than younger adults during COVID-19, likely because they had already lived through comparable large-scale disruptions.

Contrary to predictions that isolation would hit older adults hardest, Castel's research found older adults coped better psychologically than younger adults during the pandemic. He attributes this to older adults having already survived wars, financial collapses, and personal losses, giving them a frame of reference that helped them integrate the disruption rather than experience it as catastrophic.

purpose-and-connection

A positivity bias emerges with age: older adults selectively focus on and remember positive information, which may explain both repeated storytelling and the U-shaped happiness curve.

Castel describes research showing younger adults attend more to negative information (plausibly for survival value), while older adults increasingly favor positive material. This may explain why older people retell the same favorable stories, and connects to research showing happiness follows a curvilinear pattern across life, dipping in midlife and rising again afterward.

successful-aging

AI-generated voice cloning has made scams targeting older adults substantially more effective by exploiting their socio-emotional focus on family.

Castel's lab studies how scammers use urgency, emotional appeals, and family relationships to defraud older adults, who tend to have more savings and more socio-emotional investment in family members. He notes AI voice-cloning technology now lets scammers convincingly impersonate a grandchild in distress or even a deceased public figure, making a long-standing psychological vulnerability much more dangerous.

memory-formation

Books referenced

Better With Age: The Psychology of Successful Aging - Alan Castel - Castel's own book, published this year, and the throughline for the whole episode's discussion of successful aging and super-agers.
Protocols: An Operating Manual for the Human Body - Andrew Huberman - Huberman's own forthcoming book, plugged at the end of the episode; available for presale.
Steve Jobs - Walter Isaacson - Cited while discussing whether Jobs had some deeper sense he wouldn't live long, given the intensity with which he lived and built.
Principles of Neurobiology - Liqun Luo - Huberman mentions rereading his colleague's textbook cover to cover and finding unexpected enrichment in revisiting foundational material.
Principles of Neural Science - Eric Kandel et al. (Columbia) - Mentioned as the more established, larger comparison textbook to Luo's newer one.

Media referenced

Sully - movie - Referenced as the story of pilot Chesley Sullenberger's Hudson River water landing, used as an illustration of wisdom as accumulated knowledge deployed at the right moment.
Dean Potter documentary (four-part series) - show - Huberman describes a scene of a base jumper dying after using unfamiliar borrowed gear, illustrating how trained people default to habitual routines under extreme arousal.
Huberman Lab episode with Andrew Huberman's father - podcast - Castel calls it his favorite recent episode of the podcast, for showing the dynamic between an older and younger generation.

Companies

Wealthfront - Sponsor; cash account and investing platform.
Helix Sleep - Sponsor; customized mattresses, Huberman personally uses the Dusk model.
AG1 - Sponsor; vitamin/mineral/probiotic supplement.
Function Health - Sponsor; 160+ biomarker lab testing membership.
Lingo - Sponsor; continuous glucose monitor (Abbott).

Techniques and frameworks

Desirable difficulties / errorful learning - Deliberately struggling to recall something (e.g. drawing the Apple logo from memory before looking at it) produces stronger learning than passive repeated exposure.
Levels of processing / deep semantic encoding - Learning material by engaging with how it functions or interacts (verbs, not labels) rather than rote-memorizing labels produces more durable understanding.
Retrieval practice and self-testing, including AI-generated quizzes - Testing yourself on material, including having an AI tool generate a self-test, is one of the most effective ways to learn versus rereading or highlighting.
Single-leg balance test - Standing on one leg for 10+ seconds, then with eyes closed, as a quick self-assessment of fall risk; balance is trainable in a month or two via yoga or Tai Chi.
ABCs of successful aging - Castel's framework from his book: Attitude/Adapt (a positive, agentic view of aging), Balance (physical and life balance), and Connection (fewer, higher-quality relationships).
Selective optimization with compensation - Developmental theory describing how older adults narrow their range of activities to focus effort on the few things that matter most to them.
Socio-emotional selectivity theory - Laura Carstensen's theory that a shortened perceived time horizon shifts priorities toward emotionally meaningful goals and relationships, regardless of chronological age.

Summary

Andrew Huberman interviews UCLA psychology professor Dr. Alan Castel, a memory and cognitive-aging researcher and author of the new book "Better With Age," about what actually determines whether we remember something, and why cognitive decline with age is far less inevitable and far more nuanced than commonly assumed. The conversation opens on the mechanics of memory itself: Castel argues that good learning happens through productive failure, not repetition, illustrated by the well-known finding that people who have seen the Apple logo thousands of times still can't accurately recall its details unless forced to retrieve it from memory first. This extends into a discussion of memory's fundamentally reconstructive nature, using the Ronald Cotton wrongful-conviction case to show how eyewitness identification can permanently overwrite the original memory of an event, and how the same reconstructive machinery underlies both remembering the past and imagining the future.

The middle of the episode turns to everyday and prospective memory (Huberman's habit of memorizing hotel fire escape routes, both hosts' stories of fire alarms and near-disasters), and to how extreme arousal causes even highly trained people to default to ingrained habits rather than careful reasoning, illustrated by a base-jumping death captured on film. From there the conversation moves into the biology and psychology of aging directly: a randomized walking study that grew hippocampal volume by roughly 1% and improved memory a year later, the underappreciated importance of balance training for fall prevention, and the finding that subjective age (how old you feel) predicts longevity better than chronological age.

The back half of the episode is organized around Castel's research on "super-agers," older adults whose cognitive performance rivals people decades younger, and his ABCs framework for successful aging: Attitude/Adapt, Balance, and Connection, distilled partly from an interview with UCLA basketball coach John Wooden, who told Castel the two most important words in life were love and balance (and who, in a sobering irony, later died some years after a fall he didn't report because of pride). Castel and Huberman discuss socio-emotional selectivity theory, the surprising finding that older adults showed more psychological resilience than younger adults during COVID-19, and a positivity bias that emerges with age and may explain both repeated storytelling and the U-shaped happiness curve across the lifespan, with midlife as the dip.

The episode closes on more applied territory: how curiosity about specific topics can increase with age even as general curiosity declines, protecting memory for material people already care about; how AI voice-cloning has made fraud targeting older adults substantially more dangerous by exploiting their socio-emotional focus on family; and a broader meditation on wisdom versus knowledge, using pilot Chesley Sullenberger's Hudson River landing as an example of wisdom as accumulated experience deployed correctly under pressure. Castel repeatedly returns to intergenerational connection, curiosity, and a sense of purpose as the through-lines of aging well, over any single biohacking intervention.

Notable Quotes

"Memory is really a mental representation of the past, and by its very nature, it's reconstructive." - Dr. Alan Castel

"The best way to remember something is, again, failures." - Dr. Alan Castel

"The past is more unpredictable than the future." - Andrew Huberman, quoting a Russian proverb via Morgan Housel

"Subjective age is a better predictor of how long you'll live than your biological age." - Dr. Alan Castel

"The two most important words in the English language...love [and] balance." - John Wooden, as recounted by Dr. Alan Castel