Simulation vs. Theory-Theory

The debate between the "simulation" theory and the "theory" theory, initiated in the late 1980s in philosophy of mind and developmental psychology, concerns the source of everyday human competence in predicting and explaining human behavior, including the capacity to ascribe mental states. Unlike earlier controversies concerning the role of empathetic understanding and historical reenactment in the human sciences, the current debate appeals to empirical findings, particularly experimental results concerning children's development of psychological competence.

Since the 1960s it has been widely assumed that the source of this competence is a body of implicit general knowledge or theory, commonly called FOLK PSYCHOLOGY by philosophers and THEORY OF MIND by psychologists, concerning the basic internal organization of the system that controls human behavior. The theory is either inherited as an innate module comparable to Noam Chomsky's language module (e.g., Jerry Fodor, Alan Leslie) or largely developed in childhood in a manner comparable to the development of scientific theories (e.g., Alison Gopnik, Josef Perner, and Henry Wellman). It is usually understood to consist in a body of lawlike generalizations, with PROPOSITIONAL ATTITUDES, especially beliefs and desires, thought to be the chief posits of the theory. Many but not all proponents of this view think that the theory must be measured against computational and/or neuroscientific accounts of the system that controls behavior. The chief disagreement among proponents of the theory theory is between those who think folk psychology likely to be largely vindicated by cognitive science and those who believe it has been or will be shown to be radically mistaken (see ELIMINATIVE MATERIALISM).

The simulation (or "mental simulation") theory, introduced in 1986 by Robert Gordon and Jane Heal and further developed by Alvin Goldman, Paul Harris, and others, is usually, though not always, taken to present a serious challenge to the very assumption that a theory underlies everyday psychological competence. According to this account, human beings are able to use the resources of their own minds to simulate the psychological etiology of the behavior of others, typically by making decisions within a "pretend" context. A common method is role-taking, or "putting oneself in the other's place." However, like the term theory, "simulation" has come to be used broadly and in a variety of ways. The term is often taken to cover reliance on a shared world of facts and emotive and motivational charges, where there is no need to put oneself in the other's place. (Gordon calls this the default mode of simulation.) Sometimes the term is taken to include automatic responses such as the subliminal mimicry of facial expressions and bodily movements. Stephen Stich and Shaun Nichols, whose critical papers have clarified the issues and helped refine the theory, urge that the term be dropped in favor of a finer-grained terminology.

Simulation is often conceived in cognitive-scientific terms: one's own behavior control system is employed as a manipulable model of other such systems. The system is first taken off-line, so that the output is not actual behavior but only predictions or anticipations of behavior, and inputs and system parameters are accordingly not limited to those that would regulate one's own behavior. Many proponents hold that, because one human behavior control system is being used to model others, general information about such systems is unnecessary. The simulation is thus said to be process-driven rather than theory-driven (Goldman 1993).

Important differences exist among simulation theorists on several topics. According to Goldman and (less clearly) Harris, to ascribe mental states to others by simulation, one must already be able to ascribe mental states to oneself, and thus must already possess the relevant mental state concepts. Gordon holds a contrary view suggested by Kant and Quine: Only those who can simulate can understand an ascription of, for instance, belief -- that to S it is the case that p. Although no simulation theorist claims that all our everyday explanations and predictions of the actions of other people are based on role-taking, Heal in particular has been a moderating influence, arguing for a hybrid simulation-and-theory account that reserves simulation primarily for items with rationally linked content, such as beliefs, desires, and actions.

Three main areas of empirical investigation have been thought especially relevant to the debate.

  1. False belief. Taking into account another's ignorance or false belief when predicting or explaining his or her behavior requires imaginative modifications of one's own beliefs, according to the simulation theory. Thus the theory offers an explanation of the results of numerous experiments showing that younger children fail to take such factors into account. It would also explain the correlation, in AUTISM, of failure to take into account ignorance or false belief and failure to engage in spontaneous pretend-play, particularly role-play. Although these results can also be explained by certain versions of theory theory (and were so interpreted by the experimenters themselves), the simulation theory offers a new interpretation.

  2. Priority of self- or other-ascription. A second area of developmental research asks whether children ascribe mental states to themselves before they ascribe them to others. Versions of the simulation theory committed to the view that we recognize our own mental states as such and make analogical inferences to others' mental states seem to require an affirmative answer to this question; other versions of the theory seem to require a negative answer. Some experiments suggest a negative answer, but debate continues on this question.

  3. Cognitive impenetrability. Stich and Nichols suppose simulation to be "cognitively impenetrable" in that it operates independently of any general knowledge the simulator may have about human psychology. Yet they point to results suggesting that when subjects lack certain psychological information, they sometimes make incorrect predictions, and therefore must not be simulating. Because of problems of methodology and interpretation, as noted by a number of philosophers and psychologists, the cogency of this line of criticism is unclear.

The numerous other empirical questions of possible relevance to the debate include the following:

Some philosophers think the simulation theory may shed light on issues in traditional philosophy of mind and language concerning INTENTIONALITY, referential opacity (SENSE AND REFERENCE), broad and NARROW CONTENT, the nature of MENTAL CAUSATION, TWIN EARTH problems, the problem of other minds, and the peculiarities of SELF-KNOWLEDGE. Several philosophers have applied the theory to aesthetics, ethics, and philosophy of the social sciences. Success or failure of these efforts to answer philosophical problems may be considered empirical tests of the theory, in a suitably broad sense of "empirical."

Additional links

-- Robert M. Gordon


The following collections include most of the relevant papers by authors mentioned in the article:

Carruthers, P., and P. Smith, Eds. (1996). Theories of Theories of Mind. Cambridge: Cambridge University Press.

Davies, M., and T. Stone, Eds. (1995). Folk Psychology: The Theory of Mind Debate. Oxford: Blackwell. (The introductory chapter offers an excellent overview and analysis of the initial debate.)

Davies, M., and T. Stone, Eds. (1995). Mental Simulation: Evaluations and Applications. Oxford: Blackwell.

Further Readings

Fodor, J. A. (1987). Psychosemantics. Cambridge, MA: MIT Press.

Goldman, A. (1993). The psychology of folk psychology. Behavioral and Brain Sciences 16:15-28.

Gopnik, A. (1993). How we know our minds: The illusion of first-person knowledge of intentionality. Behavioral and Brain Sciences 16:1-14.

Gordon, R. M., and J. Barker. (1994). Autism and the "theory of mind" debate. In G. Graham and L. Stephens, Eds., Philosophical Psychopathology: A Book of Readings. Cambridge, MA: MIT Press, pp. 163-181.

Harris, P. (1989). Children and Emotion. Oxford: Blackwell.

Peacocke, C., Ed. (1994). Objectivity, Simulation, and the Unity of Consciousness. Oxford: Oxford University Press.

Perner, J. (1991). Understanding the Representational Mind. Cambridge, MA: MIT Press.

Wellman, H. M. (1990). The Child's Theory of Mind. Cambridge, MA: MIT Press.