Computer Simulation of Individual Belief Systems1

Abelson [ 19631 *), this complex project has not heretofore been totally outlined in print. We shall begin with several clarifying comments on the nature of our goals and the problems we have faced, thence procecding further and further into the details of operation of our sirnulation. By an individtral belief sgstem we refer to an interrelated set of affect-laden cognitions concerning some aspects of the psychological world of a single individual. In simulating such a system, our intention is not only to represent its structure of interrelationships, but also some of the processes by which the system maintains itself against the intrusion of new and potentially upsetting information. Our use of the technique of comprrtcr simiiIation is intended to maximize tlie explicitness with which we state our assumptions and the vividness with \vhich the consequences of these assumptions are made apparent. The operation of simulated belief systems can be played out on the computer and die detaiIs scrutinized in order to refine our level of approximation to real systems. The psychology of belief systems lies athwart the ancient philosophical battleground of whether inan is basically “rational” or “irrational.” Without claiming to have resolved this honorable controversy, we adopt the useful compromise position current among social psychologists that man is “subjectively rational,” i.e., rational within the constraints of his own experience and motivation. This position owes much to Heider’s5. analysis of “naive psychology,” and can be found implicitly or explicitly in the work of many “cognitive consistency” theorists ( Festinger7; Osgood and Tannenbaums; Rosenberg and Abelson3). To be sure, there is still much room within this compromise position for differences in emphasis as between motivational and cognitive components of tlie total system. The work of Rokeach9 and Smith, Bruner, and White’” among others reminds us that individual belief systems are heavily determined by personality needs. Our