the key to stickk really is one of being self- aware.what is the right amount that is enough that you'll be honest with yourself if you fail-- be able to pay it if you fail, but enough so that it'll actually motivate you to change? >> reporter: while karlan is no longer involved with stickk, he still regularly incorporates insights from behavioral economics into his everyday life. >> when we order dessert, "i just want one bite. you eat the rest. but i want one bite, no more. if i ask for a second bite, i owe you $100." >> reporter: devising ways to motivate change, whether to drop more pounds or to save more money. >> to learn more about what some financial companies are doing to help you save money, visit newshour.pbs.org. >> yesterday i spoke with nell any of the usa today about the decriminallation of marijuana in washington, d.c. this past week. here is an excerpt of the conversation. what is the word in washington, d.c. >> it basically decriminalizes possession of up to an ounce of marijuana. >> if you are caught with that on your