پدیدارشناسی و هذیان: چه کسی بیگانه را در کنترل 'بیگانه' قرار داده است؟

Although current models of delusion converge in proposing that delusions are based on unusual experiences, they differ in the role that they accord experience in the formation of delusions. On some accounts, the experience comprises the very content of the delusion, whereas on other accounts the delusion is adopted in an attempt to explain an unusual experience. We call these the endorsement and explanationist models, respectively. We examine the debate between endorsement and explanationist models with respect to the ‘alien control’ delusion. People with delusions of alien control believe that their actions and/or thoughts are being controlled by an external agent. Some accounts of alien control (e.g., Frith, Blakemore, & Wolpert, 2000a) are best thought of in explanationist terms; other accounts (e.g., Jeannerod, 1999) seem more suited to an endorsement approach. We argue that recent cognitive and neurophysiological evidence favours an endorsement model of the delusion of alien control.

Current models of delusion converge in proposing that delusional beliefs are based on unusual experiences of various kinds. For example, it is argued that the Capgras delusion (the belief that a known person has been replaced by an impostor) is triggered by an abnormal affective experience in response to seeing a known person; loss of the affective response to a familiar person’s face may lead to the belief that the person has been replaced by an impostor (Ellis & Young, 1990). Similarly, the Cotard delusion (which involves the belief that one is dead or unreal in some way) may stem from a general flattening of affective responses to external stimuli (Ellis & Young, 1990), while the seed of the Frégoli delusion (the belief that one is being followed by known people who are in disguise) may lie in heightened affective responses to unfamiliar faces ( Davies, Coltheart, Langdon, & Breen, 2001). Experience-based proposals have been provided for a number of other delusions ( Breen et al., 2000, Breen et al., 2001, Davies et al., 2001, Davies et al., 2005, Langdon and Coltheart, 2000, Maher, 1988 and Stone and Young, 1997). But behind this broad agreement lies an important controversy about the precise role that experience plays in the formation of delusions. On some accounts the experience comprises the very content of the delusion, such that the delusional patient simply believes what they experience; the delusional belief encodes the content of the perceptual experience in linguistic form. We will call such accounts endorsement accounts, on the grounds that the person believes—that is, doxastically endorses—the content of their perceptual state, or at least something very much like the content of their perceptual state. 1 An endorsement account of the Capgras delusion, for example, would hold that the Capgras patient sees the woman he is looking at (who is his wife) as an imposter (that is, as someone who merely looks like his wife). Other experience-based accounts of delusion construe the relationship between delusional experience and delusional belief in explanationist terms. The patient adopts the delusion in an attempt to explain, or make sense of, an unusual experience. According to the explanationist, the Capgras patient does not perceive his wife as an impostor, rather, he simply fails to have the expected experience of familiarity when looking at his wife. He forms the belief that the woman he is looking at is not his wife in an attempt to explain his lack of affect. 2 In this paper, we employ the distinction between endorsement and explanationist models to evaluate accounts of the ‘alien control’ delusion. People with delusions of alien control believe that their actions and/or thoughts are being controlled by an external agent. Some accounts of alien control (e.g., Frith et al., 2000a) are best thought of in explanationist terms; other accounts (e.g., Jeannerod, 1999) seem more suited to an endorsement approach. We argue that recent cognitive and neurophysiological evidence favours an endorsement model of the delusion of alien control. 2. Two experiential routes to delusion Let us consider the distinction between endorsement and explanationist models in more detail. First, it should be noted that it is possible that a comprehensive account of delusions will contain both endorsement and explanationist elements. Perhaps some delusions should be accounted for in endorsement terms and others in explanationist terms. It is also possible that in some instances patients adopt delusional beliefs in an attempt to explain their unusual experience, but as a result of having adopted the delusional belief their experiences come to inherit the content of the delusion itself. For example, someone might form the Capgras delusion in an attempt to account for their strange experience of lack of affect, but having formed the delusion may come to see their wife as an imposter (see Fleminger, 1992). Experience-based accounts of delusions involve (at least) two components: (i) an explanation of the delusional patient’s experiential state; and (ii) an explanation of the delusional patient’s doxastic state (his belief). Endorsement and explanationist models face distinct challenges in providing these explanations. Explanationist models appear to have an easier job of (i) than endorsement models: the less one packs into the content of the perceptual experience, the easier it is to explain how the experiential state acquires its content. Very primitive explanationist models, according to which the delusion in question is generated by nothing more than an absence of certain kinds of affect, would seem to have rather little work to do here. But what explanationist models gain with respect to (i) they lose with respect to (ii). The explanationist holds that delusional beliefs are adopted in an attempt to explain unusual experiences. The problem with this suggestion is that delusional beliefs are typically very poor explanations of the events that they are supposedly intended to explain. More plausible explanations of their strange experiences are available to the patients, some of which might be actively recommended to them by family and medical staff. Furthermore, delusional patients do not appear to hold their delusions in the tentative and provisional manner with which explanations are usually held. Explanationists are well-positioned to account for the content of the patient’s experiential state, but they face problems in explaining why the patient refuses to acknowledge the implausibility of the delusional beliefs they adopt in response to those experiences. By contrast, endorsement models would seem to have a more plausible story to tell about how delusional patients move from experiences to belief. Perhaps, as Davies et al. (2001) suggest, delusional individuals might have difficulties inhibiting the pre-potent doxastic response to their experiences. Seeing is certainly not believing, but the transition from perceiving ‘that P’ to believing ‘that P’ is a familiar and attractive one. Of course, things are not completely plain sailing for the endorsement theorist. For one thing, we would need to know why delusional patients fail to take account of their background beliefs; why do they fail to inhibit the pre-potent doxastic response in the way that a ‘healthy’ person presumably would, if faced with the same bizarre and implausible sensory experience?3 But on the face of things the endorsement account looks to have a more plausible account of why, given the experiences that the account ascribes to the patients, they go on to form the beliefs that they do. Where the endorsement account would appear to be weakest is in explaining how delusional patients could have the experiences that the account says they do. We return to this point below. How does the distinction between endorsement and explanationist models map on to the better-known distinction between one-deficit and two-deficit accounts of delusions? One-deficit accounts, such as Maher’s (Maher, 1974), hold that the only impairments delusional patients have are perceptual: their mechanisms of belief-fixation operate within the normal range (although they might be biased in some way). Two-deficit accounts, by contrast, hold that delusional patients have belief-fixation processes that are outside the normal range. The distinction between one- and two-deficit accounts is orthogonal to the distinction between explanationist and endorsement accounts ( Davies et al., 2001). Both endorsement and explanationist models can be developed in either one-deficit or two-deficit terms. Consider first the endorsement account. As the Müller–Lyer illusion demonstrates, normal individuals do not always believe ‘that P’ when confronted with the perception ‘that P.’ And although the explanationist model of delusions might be thought to suggest a two-deficit view, it can be developed in one-deficit terms. Whether or not the explanationist will need to invoke a belief-formation abnormality depends on whether a normal individual would form (and maintain) the sorts of explanations of their unusual experiences that delusional patients do ( Bayne and Pacherie, 2004a and Bayne and Pacherie, 2004b). These distinctions allow us to notice that one way one might be tempted to argue for a two-deficit account is fallacious. It is sometimes suggested that the discovery of two individuals who share the same experiential abnormality, but only one of which was delusional, would weigh decisively in favour of a two-deficit account of delusions. The logic behind this claim is that we would need to appeal to a second (belief-fixation) deficit to explain why only the delusional individual adopted the delusional belief in response to the unusual experience. But this inference is fallacious: for all we know, a vast range of belief-fixation processes fall within the normal range, and it is quite possible that there will be individuals who share exactly the same phenomenology, and whose belief-forming processes are within the normal range, but only some of which go on to form delusional beliefs. Two individuals, S1 and S2, could reason from exactly the same types of experiential states, via different but normal belief-fixation procedures (doxastic styles), to quite different doxastic states; S1 might put a higher premium on theoretical simplicity than S2, while S2 might put a higher premium on mechanistic explanations than S1. The dissociation argument would show that belief-forming processes must play a role in the formation of delusional belief, but it would not show that delusional individuals have a beliefs-forming deficit. 4 Although recent accounts of delusions have generally been quite vague about both the content of the abnormal experiences they posit and the precise way in which such experiences generate delusional beliefs, most theorists seem inclined towards explanationism. Young and Leafhead (1996) suggest that Cotard and Capgras patients arrive at different delusional states because they adopt different explanatory strategies towards the same abnormal experience of loss of affect: Cotard patients are depressed, and as a result they explain their loss of affect in terms of a change to themselves, while Capgras patients are suspicious, and as a result they explain their loss of affect in terms of changes to their environment. One could have reason to challenge this attractive suggestion if, as Gerrans argues, there is reason to think that the Cotard and Capgras delusions are grounded in distinct phenomenal states (Gerrans, 2002).5 Gerrans himself seems to adopt an explanationist account of the Capgras delusion. He argues that “The Capgras person does not perceive the other person as a double. Rather she perceives the other person and, while doing so, has a very atypical affective experience. Because this experience occurs in a context in which, normally, perception is coupled with a recognition judgment, she infers that the person she is seeing is a double” (2002, p. 67). One reason for the widespread sympathy with explanationist models may be the view that the relationship between perception and belief is typically explanatory. Some theorists think of perception in general, and emotional and affective states in particular, as non-representational. On this view, perceptual beliefs are adopted in the attempt to explain our perceptual states: I believe that I am looking at a cat in an attempt to explain certain sensations I am currently having. Such explanationist approaches to the perception-belief interface should be rejected. There are two central respects in which they fall short. First, the explanationist needs to explain how the adoption of perceptual beliefs (such as “this is a cat”) could explain the sensations in question. Exactly how this explanation might go is anything but clear. Second, the proposal flies in the face of phenomenology. Our experience of the world is shot through with representational content. This is clear in the case of visual perception, as the much discussed Müller–Lyer illusion demonstrates: the two lines appear to be of different lengths, even when one believes that they are the same length. But it is worthwhile pausing to consider the degree to which other facets of experience also have representational content. Think of the patient with phantom limbs, who experiences her phantom limb as reaching for a door, even though she knows that she is performing no such action. Think of what it is like to watch Heider’s visual stimuli (Heider & Simmel, 1944), where one sees the geometrical stimuli as intentional entities (“the big square is chasing the small triangle”). In all of these cases, one has perceptual experiences that naturally give rise to beliefs with the same content unless (slow, conscious) processes of doxastic inhibition intervene. Given that our experience of the world is rich with representational content, it is not implausible to suppose that the dominant experience-based route to belief takes an endorsement form.

We began this paper with the distinction between endorsements and explanationist accounts of delusion: endorsement theorists hold that the content of the delusion in question is encoded in the patient’s perceptual experience, explanationists hold that although the delusion is grounded in an unusual experience of some kind, the content of the delusion results from the patient’s attempt to explain this unusual experience. Our goal in this paper has been to develop an endorsement-based account of the delusion of alien control. We distinguished four aspects of the content of alien control delusions: passivity, externality, agency, and particularity. We saw that Frith’s central-monitoring account gives us a way to understand how it is that a person could experience their willed actions as passive and external. But Frith’s account does not take an endorsement approach to either the agency or the particularity components of alien control. To develop an endorsement account of alien agency we turned to Jeannerod’s simulationist account of action monitoring, arguing that the inherent inter-subjectivity of his model gives us a way in which a person could experience their own actions as the actions of someone else. We finish with some outstanding questions. First, we still need to account for particularity: why do patients with alien control delusions believe that particular agents are controlling their actions? Is this also encoded in their experience, or do we have to appeal to explanationist principles at this point? Second, there is what Gallagher (2004) calls the problem of specificity. Why do patients with alien control regard only some of their actions as under the control of other agents? Because this issue is orthogonal to the debate between endorsement theorists and explanationist theorists we have left it to one side here, but it is clearly a pressing one for accounts of the delusion of alien control, no matter what form they take.