It's not a novel, but I can highly recommend 'Influence: Science and Practice' by Professor Robert B. Cialdini.
It is a detailed description of research into how people are influenced and the ways in which this information is used by marketers, salesmen and politicians to get what they want out of us.
Ever wondered why the payment slip sent to you by that charity 'suggests' donations of £250, £100, £10, £1? (Answer: they are trying to get you to donate £10. The £1 looks really small compared to the other figures so you'd feel guilty only giving that if other people are giving as much £250. If you give £10, you are 'saving' £240 or £90 compared to the biggest two figures, and you are giving ten times as much as the cheapskates who only pay £1.)
Why does the door-to-door salesman tell you that Mrs. Jones down the road just bought three 'widgets'?
'Everything must go!' How does that persuade people to buy?
Why do people in cities walk by motionless bodies lying in the street, but in small villages would stop to offer assistance?
Some of the discoveries are really amazing.