The pamphlet reviews cognitive and developmental psychology research in which skilled and less skilled performance patterns and mechanisms have been compared. Knowledge has been described, in theory, in terms of an associative network in which concepts are represented as the nodes of the net, and relations between concepts serve as associative…

External representations have a great impact on what and how students learn. One key manner in which environments can operate upon novices' knowledge is through helping them ground their problem solving in an understanding of the situation embodied by the problem. In this paper, students' difficulties in microeconomics problem solving were…