You ask someone to do you a favor and they decline; what do you do next?
According to two experiments carried out by Boster and other researchers, most people ask “why not?” and then try to deal with the objections (Boster et al., 2009). The trick is to transform the “no” of the refusal into an obstacle which can be overcome. By dealing with with this obstacle, your request is more likely to be granted.

Boster and his researchers tested this approach in comparison with three other methods which are known to improve the chances of obtaining a request. -Door-in-the-face: this involves making a significant request initially, which has a good chance of being refused. The metaphoric door is shut in your face. However, just after, a smaller request is made, which in comparison seems very reasonable. This second request has an excellent chance of being accepted.
-Foot-in-the-door: this approach is the opposite of the door-in-the-face. Firstly, a small request is made that has a good chance of being accepted, which is then followed by a more significant demand. The latter has a greater chance of being accepted too.
-Placebo information: You ask someone to do something and you justify why, even if this justification is unclear or arbitrary, for example: “Can I use the photocopier before you as I have some copies to make?” This technique can work in a number of cases.

Using these three methods, in comparison with the “why not” technique, the researchers determined that the “why not” technique was the most effective. In this case, passersby were asked to look after a bicycle in the street for 10 minutes, or to volunteer their spare time for a good cause. More people were willing to do this when the “why not” technique was used.

According to the researchers, the success of this technique is almost certainly linked to its persistence. A repeated request gives an impression of urgency, which in turn affects the decision-making process, either making us feel guilty or giving us a sense of sympathy. Another explanation has to do with cognitive dissonance, a phenomenon which occurs when we encounter ideas which conflict with our existing beliefs or values. The individual experiences a form of “mental anguish,” and will naturally try to reduce this stress to achieve some form of coherence or agreement. After all, if there’s no reason not to do something, why not do it?

These techniques are even more powerful when combined. The only disadvantage to the “why not” technique is the necessity to be prepared for the diverse objections which may follow. In this case, as in any negotiation, relevant responses must be prepared in advance.