In a study reported in the MIT Sloan Management Review, more than 200 executives were asked to reconnect with such people and to use their interactions to get information or advice that might help them on an important work project. The executives reported that the advice they received from these dormant sources was, on average, more valuable and novel than what they obtained from their more active relationships. In fact, many of the “weak ties” activated by Granovetter’s job hunters were connections developed earlier in their careers that had been dormant.

What makes a contact useful for a job change, argued Granovetter, is neither the closeness of our relationship with them nor the power of his or her position. It is the likelihood that the person knows different people than we do and, therefore, bumps into different information. The acquaintances, neighbors, and coworkers who operate in the same spheres as we do can rarely tell us something we don’t already know because they hear about the same things we do. Of course, having an Ivy League, Oxbridge, or Grande École connection can dramatically improve one’s prospects for moving into certain closed circles.

Our close contacts don’t just blind us, they also bind us to our outdated identities. Reinventing involves trying on and testing a variety of possible selves. But our long-standing social networks may resist those identity experiments. Remember Gary McCarthy’s chagrin when he learned, three years out of college, that his family had already pegged him as a “finance person”? Without meaning to, friends and family pigeonhole us. Worse, they fear our changing.

An academic study conducted by professors Gianpiero Petriglieri, Sue Ashford, and Amy Wrzesniewski, for example, found that successful professional gig workers take special care to build their “tribe,” a handful of sustaining relationships with peers. As one person in their study told them, “My ability to process, develop, and grow as a human being and understand who I am in the work I’m doing comes from the conversations that I have with these folks. These people are how I know what I’m supposed to be doing.

The sociologist Mark Granovetter has done important research showing the crucial significance of these casual ties. People we know only peripherally, Granovetter has argued, create important bridges to new social networks.