If we’re trying to persuade a skeptical audience to believe a new message, the reality is that we’re fighting an uphill battle against a lifetime of personal learning and social relationships. It would seem that there’s nothing much we can do to affect what people believe. But if we’re skeptical about our ability to affect belief, we merely have to look at naturally sticky ideas, because some of them persuade us to believe some pretty incredible things.

Expected outcomes should be noted in writing, in advance. Specificity is crucial. Rather than stating “increase in market share” or “market leadership,” quantify a thoughtful range within which you would declare success and below which you would not. Without such defined measures, you can fall prey to the human tendency to rationalize any outcome as more or less what you expected.

Instead of swirling downward into frustration, “Yes and” spirals upward toward possibility. When you stop you’ve got a set of options, not a sense of futility.

There are certainly plenty of times in life to say “No.” When it comes to moving others, however, the best default position is this second principle of improv. And its benefits stretch further than sales and non-sales selling.

Professor Sheena Iyengar from the Columbia Business School is a psycho- economist who specializes in decision making. Her famous “jam study” was done using specialty jams in a grocery store. One week, the researchers set up a table in the store showing off six different specialty jams (with snazzy flavors like kiwi-orange, strawberry-lavender...you get the idea). Then they watched how the shoppers behaved—who stopped to look and, of those who stopped, who actually bought some jam. The first week, with six jams on display, 40 percent of the shoppers stopped to check out the six jams and about a third of them bought one—about 13 percent of the shoppers.

A few weeks later, in the same store, with the same time frame, the researchers came back with twenty-four jams. This time, 60 percent of the shoppers in the store stopped by—a 50 percent increase over the six-jam display! But with twenty-four jams on display, only 3 percent of the shoppers bought one.

Dan Gilbert at Harvard has looked at this area and demonstrated the effect letting go of your options has, in a study evaluating how people made decisions about different Monet art prints. He asked people to rank five different Monet prints according to their preference, numbering them from one to five. Whichever prints the subjects ranked numbers three and four he said the experimenters happened to have spare copies of and were letting subjects take one home with them. Of course, most of the people took the one they had ranked number three. Then, interestingly, the experimenters told some of the people that they could swap the one they took for the other one later if they wanted to, and the other people were told that whatever print they took home was it—no swapping.

After a few weeks, the experimenters checked back with the subjects. The people who had been told they could swap their prints—even though they had not done so—were less happy with their choices than the people who had chosen the exact same prints but had been told the choice was irreversible. It turns out that reversibility is not conducive to establishing reliable happiness with a decision. Apparently, just the invitation to reconsider and “keep your options open” makes us doubt and devalue our choice.