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

Memory is not a perfect recording of the past. Alan Castel describes it as a mental representation that is reconstructed, which helps explain why two people can witness the same event and recall it differently later. The episode’s opening example makes the limits of familiarity concrete: people see the Apple logo constantly yet may not know which side has the bite or whether the mark includes a leaf. Repeated exposure can create a feeling of knowing without reliable access to details.

Castel connects this gap between confidence and actual knowledge to metacognition: awareness of one’s own thinking. His childhood line in The Wizard of Oz illustrates how rehearsal did not prevent him from swapping “cyclone” and “cellar” on opening night. Later, he could recite much of the periodic table through mnemonics but realized in college that recall did not mean he understood chemistry. These stories distinguish fluent repetition from durable, usable knowledge.

A more demanding form of practice can expose what is missing. Castel asks students to draw a familiar logo from memory, struggle with uncertain details, and then check it. That effortful retrieval reveals errors that passive review can hide and can improve subsequent learning. Mnemonics may help attach arbitrary names to familiar cues, but they add effort and can create predictable confusions; Castel therefore emphasizes repeated retrieval and using a person’s name in conversation while recognizing that remembering the substance of an interaction may matter more than remembering a label.

The conversation treats mistakes as useful signals when they are followed by corrective feedback. Castel argues that trying to draw a logo from memory—even inaccurately—forces a learner to inspect details that passive exposure leaves unnoticed. He extends the idea to everyday settings: people may repeatedly pass a fire extinguisher without registering its location, while actively searching for it makes the object and its context salient. The distinction is between seeing information and consciously noticing it.

Huberman proposes that plasticity is prompted by a gap between current ability and a desired performance. Castel agrees that this gap can feel uncomfortable and frames it as a metacognitive moment: recognizing what one does not yet know. In self-directed learning—such as learning an instrument, language, or interpersonal skill—progress depends on persistence, curiosity, and asking questions that generate useful feedback. The discussion does not equate discomfort alone with learning; the productive element is engaging with the gap and using the feedback.

Huberman speculates that frustration and agitation may accompany catecholamine activity around synapses, then reframes the beginner’s uncertainty as part of the conditions that permit learning. He wonders whether skilled learners experience the same arousal but interpret it differently, as a recognizable state rather than proof of failure. This is presented as a possibility in the conversation, not as a finding established by the cited examples.

Castel thinks mindset can influence learning, but he grounds it in goals and curiosity rather than in a slogan about growth mindset. Learning for a test differs from learning through observation and conversation about a personally meaningful interest. Curiosity can be understood as the pull between what someone currently knows and what they want to know. It can sustain exploration, though an endless sequence of videos can also consume time without a clear purpose.

When asked whether older adults should keep learning new material or focus on maintaining what they know, Castel argues for both. His father continued playing familiar piano pieces in his eighties and nineties, while travel and conversation with people who hold different perspectives can introduce novelty. Castel also challenges small routines—such as taking a different route or trying a different restaurant—as ordinary ways to encounter something new. These examples illustrate variety, not a claim that any one activity prevents age-related decline.

Routines can be useful and protective, Castel says, but they can also narrow experience. He notices students repeatedly choosing the same classroom seats and sometimes asks them to switch, so they see the room from another vantage point. He suggests that a change in physical perspective may also affect how an experience is encoded or later remembered. The episode presents this as a practical observation, not a quantified intervention.

Changing study or activity contexts may help distinguish one experience from another. Castel recalls that taking classes in different rooms made it easier to mentally revisit what he learned in each place, whereas studying everything in one setting can create interference. Huberman describes changing seats at scientific meetings to stay alert. With experience, he became more willing to take a walk when a talk was not working for him. Castel interprets this as metacognitive knowledge: learners can notice which conditions help them and adjust accordingly.

The conversation then turns to emotion and memory. Huberman observes that a public mistake can leave a strong memory of embarrassment, sometimes overshadowing the correct answer itself, and asks whether memories carry emotional tags of varying intensity. This is posed as a question for discussion rather than a conclusion; it highlights that remembering an event includes both its information and the experience attached to it.

Castel suggests that memories often carry emotional weight. He notes that the amygdala, involved in emotion processing, remains active across aging even as other brain regions tend to decline. Some memories provide comfort, others are bittersweet or frightening, and recollection can shift to fit how a person understands the past. He mentions trauma research as one example of efforts to help people whose memories remain distressing; the discussion does not imply that emotional memories are always accurate.

Castel’s childhood stage mistake became a durable memory, though he is unsure of every detail. He attributes the error partly to distraction and the difference between rehearsing without an audience and suddenly performing in front of one. That experience also prompted him to question how learning works. He describes “desirable difficulties”: learning can be challenging enough to reveal what a person does not yet know, even though teachers and learners often prefer to make it easier. The point is not to make practice needlessly frustrating, but to leave room for effort and feedback.

One practical adjustment Castel adopted for presentations is to see the room beforehand. Familiarizing himself with the auditorium may raise arousal a little, but it can also make the setting feel less unfamiliar on the day. The example shows how preparation can reduce one source of uncertainty without eliminating the demands of performing.

Huberman recounts deliberately deciding to take a mental snapshot of two ordinary scenes: a park where he sat with his first girlfriend and a Manhattan street viewed from a car. Years later, he can recall aspects of the scenes, such as the viewing angle or the construction scaffold, but is unsure whether he remembers the original details or the later act of intentionally encoding them. The distinction raises a useful question about what a remembered image actually preserves.

The scenes were not highly emotional, while a school prom was more emotionally charged but did not leave him with a comparably vivid visual picture. Huberman wonders whether the act of consciously deciding to remember contributed more to the ordinary scenes than emotional intensity did. The episode presents this as a question about autobiographical memory, not as a settled comparison between intention and emotion.