An Investigation into Adaptive Shifting in Knowledge Transfer

An Investigation into Adaptive Shifting in Knowledge Transfer Timothy J. Nokes (tnokes@uiuc.edu) Beckman Institute University of Illinois at Urbana-Champaign Urbana, IL 61801 U.S.A. Abstract Participants were trained on three knowledge types -- exemplars, tactics, and constraints -- and then thought aloud while solving a series of transfer problems. Results show that participants shift between the transfer mechanisms of analogy, knowledge compilation, and constraint violation depending on their prior knowledge and the characteristics of the transfer tasks. Introduction A central goal of cognitive science is to develop a general theory of transfer to explain how people use and apply their prior knowledge to solve new problems. To construct such a theory scientists need to identify and articulate the cognitive processes involved in the access, retrieval, and application of prior knowledge to new situations. Previous work has taken a ‘divide and conquer’ approach to attaining this goal. Researchers have pursued separate lines of inquiry by investigating the cognitive processes of transfer for particular learning and problem solving scenarios. This work has led to the development of several specialized theories of transfer including analogical transfer (Gentner, 1983), knowledge compilation (Anderson, 1983), constraint violation (Ohlsson, 1996), and transfer appropriate processing (Morris, Bransford, & Franks, 1977), among others. Although this research has contributed to our understanding of particular kinds of transfer, it has done little to address how these transfer processes interact and relate to one another. A complementary research strategy is theory unification. If our ultimate goal is to develop a general theory of transfer we need to articulate how the local theories ‘fit together’ within a larger cognitive framework (Newell, 1990). If each theory postulates a particular kind of transfer mechanism, then those mechanisms must eventually be realized within one and the same cognitive system. The purpose of the current work is to take the first steps towards this goal by synthesizing across previous theories of transfer in an effort to elucidate how a subgroup of transfer mechanisms relate to and interact with one another. Building upon previous work, I investigate whether people are capable of dynamic shifting between multiple mechanisms of transfer depending on their prior knowledge and the characteristics of the transfer tasks. Theories of Transfer The three theories of transfer investigated in the current work are analogy, knowledge compilation, and constraint violation. These theories are of particular interest because each proposes a computationally well-defined transfer mechanism that operates on different types of knowledge structures. In this section I briefly review each theory and describe their scope of application. Analogical transfer consists of three main parts: retrieving a prior analogue from memory, aligning and mapping the analogue to a target, and then drawing an inference from that mapping to the target scenario (Gentner, Holyoak, & Kokinov, 2001). Analogical transfer operates on exemplar knowledge that is typically assumed to be a declarative representation, but it can also include procedural attachments (Chen, 2002). Prior empirical work has shown that analogical retrieval is facilitated by surface feature similarity to the target scenario (Catrambone, 2002) whereas alignment and mapping is facilitated by structural similarity (Gentner, Ratterman, & Forbus, 1993). These results suggest that analogy is triggered by tasks that are similar on the surface and share the same relational structure. Knowledge compilation is a method by which prior declarative knowledge (instructions, tactics, or facts) can be used to solve novel problems and perform new tasks. It can be viewed as a translation device that translates prior declarative knowledge into a set of procedures and actions for performing a particular task or solving a specific problem. Knowledge compilation operates through the deliberate and explicit, step-by-step interpretation of a declarative statement that generates new procedures (production rules) as a side effect. Those rules are later optimized via rule composition, and the result is a procedural representation of the declarative knowledge given a particular goal (Anderson, 1983; Taatgen & Anderson, 2002). Previous work has shown that declarative knowledge can apply to a variety of different tasks but is costly in terms of the time required to proceduralize that knowledge to the current problem context (Nokes & Ohlsson, in press). Constraint violation is a three-part process that involves a generate-evaluate-revise transfer cycle in which a learner uses prior knowledge of the domain constraints to evaluate and correct her or his task performance (Ohlsson, 1996). According to the theory the learner generates an initial solution based on general problem solving strategies and then evaluates that solution with respect to her or his prior knowledge of the constraints. If a constraint is violated, the learner attempts to revise the faulty procedure(s) and generate a new solution. This process is repeated until a correct solution is found that satisfies all of the constraints. Transfer is the process by which the learner uses her or his