Is a behavior modification technique that rewards appropriate behavior with tokens that can be exchanged later for desired goods and/or privileges.

The answer in the blank is token economy. It is a way of having the targeted behavior to be made with the use of the tokens which represents as a symbol that could be exchanged into something that the person would desire, in order to have this, the individual will likely behave in order to get the token from the one who is going to give it.