Dr. David Eagleman Talks About Tacit Knowledge & How We Learn

The central claim is that most of what drives human behavior—especially learning and expertise—happens without conscious access. David Eagleman frames the brain as an enormous system (about 100 billion neurons and thousands of trillions of connections) that people experience only indirectly: damage to the brain can reshape personality, decision-making, and risk-taking, yet individuals still can’t “see” the machinery behind their choices. That mismatch—being “your brain” while lacking access to most of its operations—sets up a practical focus on how knowledge is acquired, stored, and used.

Eagleman then connects neuroscience to knowledge management through a two-track model of learning. One track is unconscious, feedback-driven learning that produces tacit or implicit knowledge—skills people can perform but struggle to describe. He illustrates this with “chicken sexing,” where poultry workers sort newly hatched chicks by sex despite the birds looking nearly identical at two days old. Training in the U.S. failed to produce transferable instruction, but a Japanese approach worked: trainees make a best guess while a master stands over them, giving only yes/no feedback. Over time, accuracy rises while the underlying method remains hard to verbalize. A similar pattern appears in World War II plane-spotting in England, where expert roof observers couldn’t explain their judgments, but could still train others through repeated yes/no confirmation.

The second track is more conscious and deliberate: learning that requires stepping off autopilot. Eagleman argues that routines—driving the same route, using the same hand, repeating the same daily patterns—reduce neural effort by turning behavior into low-resistance pathways. Getting “off autopilot” is exhausting at first, but it can build new connections. He links this to cognitive resilience using research on nuns in New York who donated brains after death: roughly a third had Alzheimer’s pathology without showing symptoms. The proposed mechanism is “cognitive reserve,” built through ongoing socializing, responsibilities, and mentally engaging activities (including smartphone use), which keeps the brain forming alternative routes for problem-solving.

From there, Eagleman shifts to an urgent workplace problem: retiring experts carry away tacit knowledge that takes years to accumulate, while organizations can’t always afford that time. He suggests bridging the gap by making learning relevant and engaging rather than dumping information. He contrasts “just in case” teaching (preloading facts) with “just in time” learning (looking up what’s needed when curiosity and context are present). He also endorses testing before formal learning as a way to create the right mental state—an approach echoed in guided, question-based teaching traditions.

Finally, Eagleman broadens the knowledge theme beyond individual cognition. He argues that social neuroscience shows brains treat corporations using the same circuitry as people, shaping trust, reputation, and integrity judgments. Branding, in this view, isn’t just about price or design; it’s about the social meaning people assign to an organization—whether it feels “cool,” responsible, and trustworthy. He closes by tying knowledge management to civilization-scale survival: the internet’s redundancy and archiving reduce the risk of catastrophic knowledge loss (from events like the Library of Alexandria burning), and faster dissemination—such as through biomedical databases—can prevent repeated “reinvention” of medical discoveries and the deaths that follow when knowledge doesn’t spread.