Companies can analyze, engineer, and elevate their own human networks, says the pioneering social scientist.

Think back to a conversation you had months ago with someone you know well enough to trust, but with whom you haven’t spoken since. Chances are you’ll remember only vague outlines of the exchange. Call the person and raise the same subject again, though, and more likely than not, the two of you will find yourselves picking up where you left off, remembering the details of significance and expanding into new areas.

To Karen Stephenson, a maverick yet influential social network theorist, the association between trust and learning is an instrument of vast, if frequently untapped, organizational power. The act of reconnecting and talking with a trusted colleague generally triggers a resurgence of mutual memory, opening the gates to fresh learning and invention. This phenomenon, Professor Stephenson contends, is just one example of the direct cognitive connection between the amount of trust in an organization and its members’ ability to develop and deploy tacit knowledge together. Because networks of trust release so much cognitive capability, they can (and often do) have far more influence over the fortunes and failures of companies from day to day and year to year than the official hierarchy.