The psychology of legal relations
Documented in Robert Cialdini’s seminal book on persuasion techniques, Influence: The Psychology of Persuasion, one of the six is commitment. Lead your counterpart up the garden path with a series of leading questions, at the end of which, like poor old Bernard, he has no choice but to give you the answer you want — unless he wants to flat-out contradict himself, or mount a sophisticated, complicated and quite confrontational reverse-ferret.
In a nutshell
Early in the sales pitch, commit your counterpart to an uncontroversial factual statement — especially one that by ego, she is disposed to agree with — and which is consistent with the outcome you are trying to achieve. Later, the countepart will have difficulty arriving at an inconsistent conclusion. For example: “do you like fine arts and classical music?” Now, what self-respecting culture vulture would not agree with that? Who would want to come across to that nice young lady (see — “liking”) as some kind of Philistine? “Why I do.” Your eyes twinkle. “A particular fan of the pointillistes.” But then comes the sucker punch: “Great — so a person of such exquisite taste can hardly refuse the chance acquire some vouchers to buy half-price entry to galleries and classical concerts...”. Your play here is to either climb down and admit to that nice young lady that you are a Philistine and not only that you were bluffing about it — or you could suck it up and buy the stupid coupon book...
Is the commitment gambit legitimate? Depends. On one hand, it is easy and tempting to use it for nefarious ends: it is a fake news bonanza. Will you ever believe an opinion poll again? But it was ever thus.
On the other, if you want to achieve an outcome — and let’s face it, friends, all but the most passive aggressive of us generally do — and you have the choice between doing this the easy way or the hard way, wouldn’t you take the easy way?
And bear in mind it is a competitive market. If you don’t, someone else will. And guess who will get the deal.
That is to say, it may be logical to present matters in a dry, dispassionate and infinitely particularised way, but it isn’t, as Rory Sutherland would say, psycho-logical.