The upgrading method first endows a participant with a product profile and then allows him or her to upgrade it, one attribute at a time, to a more desirable product configuration.

• 该升级方法首先赋予参与者一个产品轮廓，随后允许他/她将它产品进行升级，每次升级一个属性，使产品升级到一个令人更加满意的形态。