The upshot is clear: If you find yourself mapping a “whether or not” question, looking at a simple fork in the road, you’re almost always better off turning it into a “which one” question that gives you more available paths.

What’s the best way to expand your pool of options? Researchers suggest that if possible, you diversify the group of people who are helping make the decision. About a decade ago, the social psychologist Samuel Sommers conducted a series of mock trials in which a jury debated and evaluated evidence from a sexual assault case. Some of the juries were entirely white, while other juries were more diverse in their racial makeup. By almost every important metric, the racially mixed juries performed better at their task. They considered more potential interpretations of the evidence, remembered information about the case more accurately and engaged in the deliberation process with more rigor and persistence.

Homogeneous groups — whether they are united by ethnic background, gender or some other commonality like politics — tend to come to decisions too quickly. They settle early on a most-likely scenario and don’t question their assumptions, since everyone at the table seems to agree with the broad outline of the interpretation.

A 2008 study led by the management professor Katherine Phillips using a similar investigative structure revealed an additional, seemingly counterintuitive finding: While the more diverse groups were better at reaching the truth, they were also far less confident in the decisions they made. They were both more likely to be right and, at the same time, more open to the idea that they might be wrong.

Once you have your alternatives, how are you supposed to assess them? One approach, known as scenario planning, developed by a handful of management consultants in the 1970s, involves imagining three different future environments for each alternative: Concoct one story where things get better, one where they get worse, and one where they get weird.

Storytelling is something we instinctively do anytime we are contemplating a big decision. If you’re thinking of leaving the city and moving to the suburbs, you tell a story of family hikes through the trails behind your house, and better public schools, and a garden that you can tend in your backyard. The difference with formal scenario planning is twofold: First, we rarely take the time to do a deep analysis of all the forces that shape that story; and second, we rarely bother to construct multiple stories. How does the story unfold if your children don’t like their new classmates, or if one part of the family loves the new lifestyle but the other is homesick for the old friends and vitality of city life?

The psychologist Gary Klein has developed a variation on this technique. He calls it a “premortem.” As the name suggests, the approach is a twist on the medical procedure of post-mortem analysis. In a post-mortem, the subject is dead, and the coroner’s job is to figure out the cause of death. In a premortem, the sequence is reversed: “Our exercise,” Dr. Klein explains, “is to ask planners to imagine that it is months into the future and that their plan has been carried out. And it has failed. That is all they know; they have to explain why they think it failed.”