It is highly unlikely that a first attempt at modelling any psychological phenomenon will yield a model that a) can account for all relevant psychological data, and b) generates no new empirical predictions. Computational modelling is an iterative exercise, in which many models are typically developed and compared before the phenomena of interest can be adequately accounted for. This iteration may involve the exploration of blind alleys (sequences of models which are in some way fundamentally flawed, but where the flaw was not initially obvious) or the use of standard laboratory-based experiments to test model predictions. Either way, building a model of some phenomenon is best understood as a Research Programme (Lakatos, 1970).
Although all the dictates of a Lakatosian Research Programme may not be entirely appropriate to computational modelling, a Lakatosian approach is in many ways the most methodologically appropriate approach to take to modelling. COGENT supports the Lakatosian approach through its Research Programme Manager. This is a set of windows which treat research programmes as first class objects, and which allows the make up of an individual research programme (in terms of a directed graph of individual models) to be displayed graphically.
A rather complex research programme is shown in the following figure:
Each disc on the diagram represents a distinct model. Time within the diagram is understood to progress from left to right: models on the left side of the figure were developed (or at least initiated) before those on the right. Ancestral relationships between models are also shown on the diagram. A line linking two discs indicates that the corresponding models stand in a parent/child relatationship: the model on the right end of the line is a direct desendent of the model on the left.
Individual models within a research programme may be opened by double-clicking on their discs, but before we look at a model, we should step back and look at all of COGENT's research programme facilities.
When COGENT is first invoked it presents the user with its research programme manager window:
This window lists all of the user's projects, and gives access to various maintenance functions. For the most part these functions are obvious. Research programmes can be created, opened, deleted, renamed, and copied. They may also be archived and extracted. This tutorial won't cover many of these functions in any detail. The principal button we're interested in is Create.... This will allow us to create a new research programme, as required by the remainder of the tutorial.