Learner Control

There is a significant amount of research suggesting that students benefit most

when there are fewer restrictions imposed on the tutoring process. Providing

students with the freedom to explore and arrive at correct solutions via their own cognitive processes can improve the learning outcome (Gilbert et al., 2009). This goal can be addressed by support for non-procedural tasks, flexible solution representations, and scalable feedback, which are discussed in detail below.

4.1.2.1 Support for Procedural/Non-Procedural Tasks

Procedural tasks have a defined algorithm or method for completion. For example, there is a procedure to be followed when assembling furniture, adding fractions or carrying out a chemical reaction. There may be some flexibility in the ordering of individual steps, but there is still a defined process that arrives at a valid

4.1. DESIRABLE ITS CHARACTERISTICS 45

solution. Non-procedural tasks are less clearly defined and involve more freedom of thought. For example, writing an essay or designing a database are more open- ended tasks that do not have an exact algorithm or series of steps to be followed. There may be guidelines, such as including an introduction at the beginning of an essay and including a topic sentence at the beginning of each paragraph, but these constraints are still quite general and do not describe an exact process.

AR-based training for assembly and maintenance traditionally involves more procedural tasks that instruct the student to follow a series of defined steps. How- ever, one can imagine an AR tutor that teaches students to plant a garden or perform a similar less procedural task. The tutor may give general guidelines, such as planting certain species next to each other or how deep to dig, but it would not give the student a fixed series of steps describing exactly where each plant should go. For this reason, the chosen ITS would ideally be able to sup- port both procedural and non-procedural tasks, even though the majority of AR assembly tasks are procedural.

4.1.2.2 Accepting Multiple Solutions

Another important property to consider when evaluating an ITS is its degree of flexibility with regard to the representation of solutions. As previously mentioned in section 2.2.1, traditional rule-based (model-tracing) systems represent solutions as a collection of problem-solving procedures. They do support multiple correct solutions for a single task, but each solution must be anticipated in advance by the ITS developer and have an associated set of rules describing the procedure to be followed to arrive at the solution. Constraint-based tutors, on the other hand, describe abstract features of correct solutions via constraints. They do not detail the exact procedure for satisfying the constraints, and thus are more flexible in terms of accommodating multiple solution paths. The ITS developer does not need to anticipate all correct solution procedures in advance.

While some AR-based training tasks follow a set of defined procedures, they could also potentially benefit from the use of the more flexible solution represen- tations found in constraint-based tutors. For example, when assembling a table, it doesn’t necessarily make sense to follow a strict procedure to attach each of the

four legs. It would be possible to create a set of rules for each possible solution procedure, but that would be tedious and there might be valid solution paths that are overlooked.

In contrast, a constraint-based approach would simply state that the table must have four legs attached in the proper locations and orientations. It would then be left up to the AR interface and the student to devise a method to meet the solution requirements set forth by the tutor. If the ITS developer wanted the student to follow an exact procedure, this can still be achieved by adding additional constraints that detail a more strict solution path.

4.1.2.3 Flexible Teaching Strategy

Scaffolding is an educational concept that entails scaling the level of assistance with a task as needed based on how a student performs (Wood et al., 1976). When a student is learning a concept or skill for the first time, the system provides detailed assistance with each aspect of the learning task. As the student becomes more familiar with the task, the level of assistance is gradually scaled back until the student is able to perform the task without assistance. If the student forgets something or makes a mistake, the scaffolding kicks in and reminds the student of the proper procedure. The goal is to reduce reliance on the system over the course of the training period so that eventually the student can complete the task without assistance.

Effective ITSs are able to adjust their teaching strategy to suit each student. Prior research suggests that novice students benefit most from immediate inter- vention and feedback when mistakes are made, while more knowledgeable students benefit from less rigid instruction, which allows them the opportunity to discover and correct their own mistakes (Gilbert et al., 2009). In general, students should be given the minimum level of assistance required to successfully complete the task (via scaffolding), and a minimal level of feedback in the form of hints when a mistake is made. It is important for any ITS to be able to accommodate different styles of instruction depending on the task to be performed and the student’s level of expertise.