Influence: The Psychology of Persuasion

Robert cialdini's seminal book on the psychological techniques of persuasion list 6 types of persuasion.

• reciprocity: the classic example being the free flower from the hari Krishna at the airport so pleasingly lampooned in airplane. The idea is if you receive a gratuity, regardless of how insignificant, you feel morally obliged to reciprocate, (in the context of sales by purchasing the product)
• commitment and consistency: early in the sales patter, committing your target to even a small factual statement which then is consistent with the purchase. ( for example do you like classical music? therefore you will will want to buy my discount coupon book for classical concerts right? Uh yeah I guess so)
• authority: we are more susceptible to following instructions from people in a putative position of authority. As to this see the Milgram experiments etc
• social proof: we are joiner inners. We will tend to behave in the same way that people in our social group and of our social status behave. Therefore if you can be persuaded that that is what your peers are doing you are likely to be persuaded to do it yourself.
• liking : if you like the person selling to you you're more likely to buy from them. Therefore, Physical Attraction, agreeableness and so on are very disarming.
• scarcity: on sale now for a limited time only 4. A very simple strategy, everyone understands that, however it is surprisingly effective full stop people can be persuaded to buy products that they would not buy were they not in scarce supply.
• unity.

It should not come as an enormous surprise that a combination of these techniques is particularly effective. The same techniques can be used to good ends and ill: many are staples of unscrupulous salespeople. Some are especially susceptible to fraudsters.

See also

• the dog in the night time