I have realized that it is impossible to deal with a child without a bribe. Not because the child expects the bribe, but because we, as adults, seem to think this is the only way to evoke a desirable behavior from the child.
Of course, it is very difficult to separate out bribes from praise and rewards, both of which are necessary to encourage children. Sometimes, the line dividing them is too thin. Reward is appreciation for good behavior. Bribe is a condition you are extending to prod the child to good behavior. Of course the expectation of a reward itself can serve as a bribe sometimes, nay, most times. My daughter knows she will get appreciated if she eats herself. So frequently she will try to eat on her own and ask me to clap. If she sees someone observing her during meal time and she is in a mood to please, she will go out of her way to show that she can eat on her own, and even tell them that they are expected to clap and say good job.
As I said this is a form of bribe in itself. But I have realized that this bribe of approval is better than the other types, specially with my daughter because with these she cant insist on upfront payment and delay the expected behavior till the payment is done.
Materialistic bribes just dont work with her because she insists on upfront payment, and after receiving it may still decide it is not worth the expected good behavior. Sometimes if she was anyway planning to behave well, but we hurry in and offer the bribe, she decides the behavior is not worth it. For instance If while feeding her, if we tell her you eat this and I will give you this, there probably ends all chances of her eating it at all. Even if she intended to eat it, the minute it is paired with a bribe, she refuses to eat untill the bribe is given.
Funnily enough she seems to recognize the difference between a bribe and permission. For example, eat and I will give you the ball usually evokes a response of No, I need the ball right now. But if she asks for the ball and I say you can take the ball after eating, she accepts the condition.
I remember recently she asked for a visitor to open the sugar dabba. The lady said I will open it if you sing a rhyme for me. She took the box back with a look which seemed to say, I can find others to do this for me, but I will not sing a rhyme if you impose a condition on me 🙂
Divya Sarma's Blog 
It may be wrong, but I’m all about bribery. Especially the bribery of approval kind. Happy A to Z!
I am not for or against bribery per se. Just realize we are quite handicapped without it. But we probably need to look beyond bribes, even the reward variety, if we need to encourage intrinsic motivation in our kids.