Cognitive Tutor Authoring Tools 2.6 > Using the Tools > Working with Behavior Graph (BRD) FilesA problem for a student to solve is described in a behavior recorder data file, or BRD file. It describes the steps students should take (or shouldn't take) as links in a node-link graph. Links in the graph represent action that can be taken by the student or the tutor (in the case of a tool-performed action). Nodes in the graph represent stopping points between actions; they store no information about problem-solving.
Section 2.1, “Link Types” describes the different link types represented in a behavior graph. Section 2.2, “Navigating a Behavior Graph (BRD) in the Behavior Recorder” explains how to navigate a behavior graph.
A link can represent one of four different action types: 'correct', 'incorrect', 'suboptimal', and 'incorrect, but not modeled'. These terms are defined below.
A preferred, correct action. This type of link is traversed when matched with a student's action. A correct action link can have feedback associated with it that is displayed to the student when the link is matched; it can also have a variable number of hints that are displayed sequentially when the student requests a hint. Visual feedback to the student is commonly a green outline or green text on the component specified as the selection of the correct action.
An incorrect action. This type of link is not traversed when matched. As one cannot progress 'through' an incorrect action link, it is not possible to have links beyond an incorrect action link. This type of link can have a variable number of 'buggy' messages that are displayed to the student when they perform the incorrect action specified on the link. Visual feedback to the student is commonly a red outline or red text on the component specified as the selection of the incorrect action.
A correct action that is suboptimal. Unlike the incorrect action link, a suboptimal action link is traversed when performed; a student can travel down a 'suboptimal path'. This type of link can have a variable number of 'buggy' messages that are displayed to the student when they perform the action specified on the link. Visual feedback to the student is commonly a red outline or red text on the component specified as the selection of the suboptimal action.
An incorrect action that is not modeled by the cognitive model. This type of link is used to identify errors that should not be traced by Jess, the rule engine used in Cognitive Tutor (Jess) mode, when running an automated test with the graph (ie, Test Cognitive Model on All Steps).