Simulation Theory: Some Objections

Theory of Mind (ToM) is the label for the abilities we have to predict and explain the behaviour of others, by ascribing mental states such as belief and desire to them, or otherwise. There are two major competing theories of ToM: the Theory Theory (TT) and Simulation Theory (ST). TT holds that we understand others by having a theory of them or their behaviour. ST holds that we understand others by putting ourselves in their place. There are also different types of ST. ST(Transformation) holds that I simulate you by becoming you. ST(Replication) holds that I simulate you by becoming like you. Below I briefly address three objections to ST.

ST(Transformation) is Incomprehensible

ST(Transformation) has been questioned. Stich and Nichols provide three possible interpretations of what Gordon’s position might mean, all of which they find unsatisfactory. They note that Gordon has characterised ST(Transformation) as meaning that “we explain and predict behaviour by “imaginative identification” — “that is, [we] use our imagination to identify with others” (Stich and Nichols [p. 91]{Davies95}) in order to fulfil that aim. They quickly dismiss the first interpretation of this as meaning that we experience conscious imagery when we simulate on the grounds of phenomenological implausibility. The second interpretation involves consideration of whether the explanation is intended to cover all or merely some cases of application of ToM. Stich and Nichols think that if the change is made to `some’ then ST becomes “patently true [but] not very exciting, and […] not incompatible with TT”. (Stich and Nichols [p. 92]{Davies95}). However, since it seems that there are ambiguous cases of use of both TT and ST, the serious defence of either should lie in the claim that one of the theories explains many important cases of application of ToM and not all, so Gordon’s line should escape Stich and Nichols particular charge here. Stich and Nichols conclude though that Transformation ST involves “imaginative identification with the other” and that this is a label for “a special sort of mental act or process which […] need not be accompanied by conscious imagery” (Stich and Nichols [p. 92]{Davies95}). Stich and Nichols then ask what this means, bringing the charge that they find it incomprehensible.

There arise here immediate questions which are familiar from asking what is meant when people employ the popular locution `If I were you…’ when giving advice. The conundrum is that the person giving advice presumably means `if I were in your position with my outlook and abilities, I would do X’ whereas those abilities and that outlook might preclude being in the situation being advised upon. It does not seem plausible that the locution means `If I were you in your position with your abilities and outlook I would do X’ since a). presumably the person receiving the advice already has access to that type of suggestion and b). the advisor will not, necessarily. Daniel phrases this objection neatly when he asks “how much of myself am I to project into the other persons’s shoes” (Daniel [p. 39]{Daniel93}). The answer, of course, is `the right amount’.

I will use the term S to refer to the subject doing the simulating and O to be the target of simulation: S wishes to understand or predict the behaviour of O.

S will not be successful in simulating O if S ascribes to O abilities and experiences that are remote from those of O, irrespective of whether that profile of abilities and experiences match those of S more closely. Naturally this presents some difficulties for simulation. S’s may find it difficult to simulate O’s who are dramatically more or less intelligent than themselves.

Stich and Nichols may legitimately ask which line ST takes on the conundrum. Re-examining the argument above produces the opposite conclusion. S does not want to use S’s own abilities and outlook to predict what O will do, because to the extent O has different abilities and outlooks, S’s prediction will be wrong. A chess grandmaster should not expect a novice player to use the same defence that was used against a particular attack in his last world championship appearance, and may indeed struggle to reduce his abilities to the correct level. As a practical matter, this will not be a problem since the grandmaster will simply use his vastly superior playing skills to compensate for his lack of ability to predict what strange tactics the novice will employ. In the other direction, the novice player would do well to predict a grandmaster-level defence against his attack, but this information will not be available. So it seems as though there are difficulties in becoming the O when the O has significantly different levels of relevant ability. These difficulties seem less marked when considering information asymmetry. This is because information asymmetries are ubiquitous in everyday life, both between S and O and between the same S at different times. Step changes in ability in a single S are either much less frequent or indeed never seen; outside of perhaps some unusual pathologies.

This challenge seems equally strong on both the replication and the transformation views. If S lacks the ability to become a chess grandmaster, then S also lacks the ability to become like one, in terms of ability at least. S has however no difficulty simulating information asymmetries between S and anyone else because this is generally not related to ability differences. However, we need to remember what the challenge is, exactly. It seems to be demanding to know what is meant by becoming someone else. I have sketched out above what this might mean. Then Stich and Nichols can say that on the above outline, it looks as though ST provides a picture on which ToM will fail to produce accurate predictions when S lacks some of the relevant abilities or disabilities of O, but will perhaps be more successful when the differences between S and O are those of information asymmetry. Fine: there are systematic errors in ToM. These will need to be explained; I will do this in later work.

ST(Replication) Involves Impossible Ascriptions

One logical objection brought against Goldman by Olson and Astington is fairly easy for Goldman\index{Goldman} to deal with. The objection is to charge that Goldman “argues that the ascription of beliefs to others is done by simulating the other’s state on the basis of one’s own. But […] the only definitive evidence for ascribing belief occurs in the case of ascribing false belief. Yet one’s own beliefs are never introspectively available as false beliefs, so how could false beliefs ever be ascribed to others? That is, how could one see in another what was never experienced in one’s self?” (Olson and Astington [p. 65]{Olson93}).

What Olson and Astington mean by the surprising claim that no one ever experiences their own false belief is that very quickly on discovering conclusive evidence for the falsity of a belief, we will change that belief such that it is no longer false. Or more precisely, we will eliminate the previous belief since it has been falsified and replace it with its negation that is a new true belief. So it is true that we never have current experience of a belief that is false now. That of course, is not what ST needs. It is only true that we have no experience of our own false beliefs if it is true that we have no experience of our beliefs changing, because both of those scenarios require only that we have an ability to use memory with some non-zero accuracy to compare our current belief states with our previous ones. We can see then that Introspectionist ST(Replication) is committed to there being such a memory capacity, though not that it must always function correctly.

ST Cannot Account for Some Developmental Data

Stich and Nichols claim that there is some developmental data which can be explained by TT but not ST. In developing a response to this objection, we may also learn more about the differences between TT and ST. The data in question derive from a variant of the false belief tests, in which children are asked about the beliefs of another child sitting in front of them about the contents of a box. The box is closed, and the other child may have either looked in the box or been told what is in it. The first child will be good at answering correctly that the other child knows what is in the box when the other child has looked in the box, but younger children are bad at answering correctly when the other has child has been told what is in the box. Older children — five and up — are good at both tasks: they know that if you see what is in the box, you know what is in the box, but they also know that you know if you are told what is in the box.

Stich and Nichols claim that these data are consistent with TT but not with ST. They write that “as children get older, they master more and more of the principles of folk psychology” (Stich and Nichols [p. 262]{Stich93}). However, they say, while it is clear that even the younger children “form beliefs as the result of perception, verbally provided information, and inference” (Stich and Nichols [p. 262]{Stich93}) they do not have the latter two routes to assessing the beliefs of others. Thus they are not using their own minds to simulate others, thus ST is false, according to Stich and Nichols. Of course, Stich and Nichols are not entitled to this conclusion. They are entitled to claim that these data show that younger children are unable to use all of the capacities available to them to form their own beliefs when simulating others. Their ToM is to that extent immature. Since Stich and Nichols allow that three-year olds have immature ToM, these data do not weigh one way or the other in the TT vs ST debate.

We might on this picture suppose that the way ST abilities develop as the child matures is that more of the routes to knowledge that the child uses become available for the simulation as maturation proceeds. Perhaps exactly that just is the development in question. There is a particular time course of development of these capabilities in the case of the child’s own beliefs — there is no reason to presume that the arrival of abilities to form knowledge from perception, testimony and inference are all simultaneous — and so one would expect the same as the child’s abilities to simulate develop. This is exactly what is found. Empirical studies confirm that different ToM component abilities develop at different times. As Farrant et al confirm, “[c]hildren typically pass the diverse desires task first, followed by the diverse beliefs, knowledge access, contents false belief, and real–apparent emotion tasks in that order” (Farrant et al [p. 1845]{Farrant06}). ST may not be committed to anything by these data, but if it assumes that maturation means the child can bring more of its own abilities to bear when simulating others, ST will to that extent be supported by empirical evidence.