Sense before syntax: a path to a deeper understanding of objects

This paper describes how we have successful adapted a principled pedagogy of objects first and progressive disclosure, originally developed for teaching objects concepts through the vehicle of a pure object language, to the teaching of object concepts using Java. We employ a cognitive science viewpoint to distinguish between, and sequence accordingly, two different aspects of learning Java. We focus initially on fundamental aspects of the object model of computation, which are simple, consistent, meaningful, and hence relatively stable in memory. Aspects of the Java syntax and semantics which are contingent or arbitrary, and hence unstable in long-term memory, are deferred until after students have acquired a secure conceptual model. We use three principal techniques to assist students in acquiring programming experience of fundamental concepts relatively un-distracted by contingent detail. These measures are: interactive microworlds that allow accurate visualisation of central object concepts; a Java scripting environment that minimises the amount of syntax required, but which allows students to interact with and inspect 'live' objects in the microworlds; and an explicitly object-oriented (if verbose) programming style that reinforces object-oriented concepts. Dealing with Java-specific design peculiarities is thus deferred until students have a stable conceptual model on which to scaffold a deeper understanding of objects.