The Nature Of Expertise: Constrained And Elaborated

What is the nature of expertise?In order to answer this question, the dissertation reviews the history of psychological researches on expertise.Firstly in theory, competences of expert in every domain are mostly the result of acquired knowledge and long-term experiences. Compared to novices, experts have meaningful perceptual pattern, quickly action, exceptional memory, deeper problem representation, better self-regulatory skill, etc. Behind the expert performance are structured knowledge, such as declarative knowledge (organized knowledge) and procedural knowledge (automatic basic skill and domain-specific strategic). Because of these knowledge and their structure, expert do better than novice, and the interaction between knowledge and competence make expert performance integrated and limited in his domain, not transferred to another domain.Secondly in methodology, expert performance studied in laboratory must be up to three criterions: reliability, reproducibility, and measurability. The approach to expert performance has been divided to 7 steps: selecting subject, defining representative task, task analyses, designing study program, collecting data, protocol analyses and explanation.After these reviews, the dissertation advances a proposition: the nature of expertise is acquired domain-specific knowledge, which affects the competences essentially. For this proposition, the empirical part of dissertation aims at answering three questions: (1) Being constrained by domain-specific activities, what are the characteristics of expert's knowledge structure compared to novice? (2) How different knowledge and its structure affect problem solving? (3) How to elicit domain-specific knowledge (including declarative knowledge and procedural knowledge), and to explain the relation of knowledge and competence?In order to answer these sub-questions, according to the logic of study on expert performance, the dissertation choose Ohm Law in physics as empirical research content, select undergraduate students in physics (relative expert) and philosophy (relative novice) as subjects, adopt expert-novice comparison and case studies, do protocol analyses, and conclude that:From the quantitative data, expert has more formulas than novice. But with further qualitative discuss, the wrong formulas that novice has can be due to knowledge deficiencies. The peculiar formulas that expert has are mostly relations ofbetween-categories and between-resistors. Expert adds more conditions in their thought, but the conditions novice adds are single or invalid. Expert is inclined to quantitatively analyze the relations between different circuits, but novice is accustomed to qualitatively analyze such relations.Such differences in knowledge suggest some characteristics of expert's knowledge structure: constrained, the fact that expert adds a lot of conditions into procedural knowledge, implies that expert performance is adapted to many constraints, so expert can produce more definite domain-demanding actions; elaborated, the fact that expert has a lot of formulas in declarative knowledge, implies that expert generated more relations in and between schema, so has a large body of efficient knowledge.In problem solving, novice does a lot of errors about computation, formulas, circuit, and goes into the plight of thought. Expert uses more complicated formulas, such as proportional and interlinked relations, but novice uses some basic formulas. Expert represents problem deeply, adopts top-down strategy and goal-directed thought, and regulates the process of problem-solving efficiently, but novice represents problem in surface way, adopts down-up strategy and algorithm-directed thought, and regulates inefficacy.Such differences between expert and novice can be analyzed from their knowledge structure: given that procedure of problem-solving as production set, on the one hand, more constraints in "if parts of production system, being automatic, can make more cognitive resources plan and monitor activities, on the other hand, more elaborated...