The emulation theory of representation is developed and explored as a framework that can revealingly synthesize a wide variety of representational functions of the brain. The framework is based on constructs from control theory (forward models) and signal processing (Kalman filters). The idea is that in addition to simply engaging with the body and environment, the brain constructs neural circuits that act as models of the body and environment. During overt sensorimotor engagement, these models are driven by efference copies in (...) parallel with the body and environment, in order to provide expectations of the sensory feedback, and to enhance and process sensory information. These models can also be run off-line in order to produce imagery, estimate outcomes of different actions, and evaluate and develop motor plans. The framework is initially developed within the context of motor control, where it has been shown that inner models running in parallel with the body can reduce the effects of feedback delay problems. The same mechanisms can account for motor imagery as the off-line driving of the emulator via efference copies. The framework is extended to account for visual imagery as the off-line driving of an emulator of the motor-visual loop. I also show how such systems can provide for amodal spatial imagery. Perception, including visual perception, results from such models being used to form expectations of, and to interpret, sensory input. I close by briefly outlining other cognitive functions that might also be synthesized within this framework, including reasoning, theory of mind phenomena, and language. Key Words: efference copies; emulation theory of representation; forward models; Kalman filters; motor control; motor imagery; perception; visual imagery. (shrink)

An examination of verbal hallucinations and thought insertion as examples of "alienated self-consciousness.".

In recent years, there has been much focus on the apparent heterogeneity of schizophrenic symptoms. By contrast, this article proposes a unifying account emphasizing basic abnormalities of consciousness that underlie and also antecede a disparate assortment of signs and symptoms. Schizophrenia, we argue, is fundamentally a self-disorder or ipseity disturbance that is characterized by complementary distortions of the act of awareness: hyperreflexivity and diminished self-affection. Hyperreflexivity refers to forms of exaggerated self-consciousness in which aspects of oneself are experienced as akin (...) to external objects. Diminished self-affection or self-presence refers to a weakened sense of existing as a vital and self-coinciding source of awareness and action. This article integrates recent psychiatric research and European phenomenological psychiatry with some current work in cognitive science and phenomenological philosophy. After introducing the phenomenological approach along with a theoretical account of normal consciousness and self-awareness, we turn to a variety of schizophrenic syndromes. We examine positive, then negative, and finally disorganization symptoms—attempting in each case to illuminate shared distortions of consciousness and the sense of self. We conclude by discussing the possible relevance of this approach for identifying early schizophrenic symptoms. (shrink)

Michael Tye untangles the complex web of empirical and conceptual issues of the newly revived imagery debate in psychology between those that liken mental...

Ordinarily, if you say something like “I see a comet,” you might make a mistake about whether it is a comet that you see, but you could not be right about whether it is a comet but wrong about who is seeing it. There cannot be an “error of identification” in this case. In making a judgement like, “I see a comet,” there are not two steps, finding out who is seeing the thing and finding out what it is that (...) is being seen, so that you could go wrong at either step. The only place to go wrong is in your description of what is being seen. We usually take it that the same point applies to present-tense ascriptions to oneself of psychological states in general. You can get it wrong about which psychological state you are in, but you cannot get it right about the psychological state but wrong about whose psychological state it is. In contrast, in a room full of people, I might hear a noise and conclude, “Bill sneezed,” and in this case I could be wrong either about who it was that sneezed or about whether it was a sneeze, rather than say a death-rattle. (shrink)

It is generally accepted that there is something special about reasoning by using mental images. The question of how it is special, however, has never been satisfactorily spelled out, despite more than thirty years of research in the post-behaviorist tradition. This article considers some of the general motivation for the assumption that entertaining mental images involves inspecting a picture-like object. It sets out a distinction between phenomena attributable to the nature of mind to what is called the cognitive architecture, and (...) ones that are attributable to tacit knowledge used to simulate what would happen in a visual situation. With this distinction in mind, the paper then considers in detail the widely held assumption that in some important sense images are spatially displayed or are depictive, and that examining images uses the same mechanisms that are deployed in visual perception. I argue that the assumption of the spatial or depictive nature of images is only explanatory if taken literally, as a claim about how images are physically instantiated in the brain, and that the literal view fails for a number of empirical reasons – for example, because of the cognitive penetrability of the phenomena cited in its favor. Similarly, while it is arguably the case that imagery and vision involve some of the same mechanisms, this tells us very little about the nature of mental imagery and does not support claims about the pictorial nature of mental images. Finally, I consider whether recent neuroscience evidence clarifies the debate over the nature of mental images. I claim that when such questions as whether images are depictive or spatial are formulated more clearly, the evidence does not provide support for the picture-theory over a symbol-structure theory of mental imagery. Even if all the empirical claims were true, they do not warrant the conclusion that many people have drawn from them: that mental images are depictive or are displayed in some (possibly cortical) space. Such a conclusion is incompatible with what is known about how images function in thought. We are then left with the provisional counterintuitive conclusion that the available evidence does not support rejection of what I call the “null hypothesis”; namely, that reasoning with mental images involves the same form of representation and the same processes as that of reasoning in general, except that the content or subject matter of thoughts experienced as images includes information about how things would look. (shrink)

The abilities to attribute an action to its proper agent and to understand its meaning when it is produced by someone else are basic aspects of human social communication. Several psychiatric syndromes, such as schizophrenia, seem to lead to a dysfunction of the awareness of one’s own action as well as of recognition of actions performed by other. Such syndromes offer a framework for studying the determinants of agency, the ability to correctly attribute actions to their veridical source. Thirty normal (...) subjects and 30 schizophrenic patients with and without hallucinations and/or delusional experiences were required to execute simple finger and wrist movements, without direct visual control of their hand. The image of either their own hand or an alien hand executing the same or a different movement was presented on a TV-screen in real time. The task for the subjects was to discriminate whether the hand presented on the screen was their own or not. Hallucinating and deluded schizophrenic patients were more impaired in discriminating their own hand from the alien one than the non-hallucinating ones, and tended to misattribute the alien hand to themselves. Results are discussed according to a model of action control. A tentative description of the mechanisms leading to action consciousness is proposed. (shrink)

This paper is concerned with the problem of selfidentification in the domain of action. We claim that this problem can arise not just for the self as object, but also for the self as subject in the ascription of agency. We discuss and evaluate some proposals concerning the mechanisms involved in selfidentification and in agencyascription, and their possible impairments in pathological cases. We argue in favor of a simulation hypothesis that claims that actions, whether overt or covert, are centrally simulated (...) by the neural network, and that this simulation provides the basis for action recognition and attribution. (shrink)

It is sometimes said that reasoning, thought and judgment essentially involve action. It is sometimes said that they involve spontaneity, where spontaneity is taken to be connected in some constitutive way with action—intentional, voluntary and indeed free action. There is, however, a fundamental respect in which reason, thought and judgment neither are nor can be a matter of action. Any spontaneity that reason, thought and judgment involve can be connected with freedom only when the word 'freedom' is used in the (...) Spinozan-Kantian sense according to which freedom is a matter of 'rational necessitation', determination by reason. (shrink)

In the past dozen years a number of theoretical models of schizophrenic symptoms have been proposed, often inspired by advances in the cognitive sciences, and especially cognitive neuroscience. Perhaps the most widely cited and influential of these is the neurocognitive model proposed by Christopher Frith (1992). Frith's influence reaches into psychiatry, neuroscience, and even philosophy. The philosopher John Campbell (1999a), for example, has called Frith's model the most parsimonious explanation of how self-ascriptions of thoughts are subject to errors of identification. (...) "On reflection, it also seems that this is not just one possible theory; it is the simplest theory which has any prospect of explaining the sense of agency, and we ought to work from it, introducing complications only as necessary" (1999a, p. 612). Not everyone agrees. In their recent analysis of alien voices and inserted thoughts in schizophrenia, Stephens and Graham (2000) offer a critique of Frith. Their criticism, however, although serious, is neither deep nor extensive. They outline three points. First, Frith fails to provide an adequate account of why a subject who experiences thought insertion would misattribute that thought to some other agent. Second, Frith does not clarify the distinction between thought insertion and thought influence. And third, Frith fails to explain how a subject can claim both that he is thinking the thought and that the thought is someone else's thought (Stephens and Graham.. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Philosophy, Psychiatry, & Psychology 9.1 (2002) 35-39 [Access article in PDF] The Ownership of Thoughts John Campbell Keywords: schizophrenia, thought insertion, immunity to error through misidentification. SYDNEY SHOEMAKER FORMULATED a basic point about first-person, present-tense ascriptions of psychological states when he declared that they are, in general, immune to error through misidentification (Shoemaker 1984). Assuming Shoemaker's point to be correct, the puzzle it raises is this: how are we (...) to explain this datum? Why should it be that first-person, present-tense ascriptions of psychological states are immune to error through misidentification? One type of explanation is in terms of the meaning of the first person: that "I" just stands for whoever is the owner of these (demonstrated) psychological states (including any states being self-ascribed). I argued against this account of the first person in a number of places, and in favor of an alternative explanation of Shoemaker's datum. On the alternative explanation, the reason for the immunity is provided by an account of the ownership of psychological states, on which what makes a psychological state mine is the possibility of self-ascription of it by me (Campbell 1986, 1999a). Suppose we call this the Introspectionist explanation of the immunity to error through misidentification of present-tense self-ascriptions of psychological states. I do think, though, that the simple Introspectionist account is too simple an account of Shoemaker's datum (Campbell 1999a, 1999b). The reason is that there is a certain complexity in our notion of the ownership of a token thought. We cannot give a full account of our ordinary notion of the ownership of a thought simply in terms of the person who is capable of introspective knowledge of the thought. The reason is that there is another dimension to our ordinary notion of the ownership of a thought. We also think of the possessor of a thought as being the person who generated that very thought; we think of the owner of the thought as being the person who brought that particular token thought into existence, the person who formed it. Of course, that token thought may be a copying of someone else's idea; that other person may have influenced my formation of that particular thought. But the point remains that I play a special role in the production of my thoughts.Suppose we have a document bearing a signature and we ask, "Whose signature is that?" In this case we are asking about the authorship of the signature; we are asking who made those particular marks on that bit of paper. Of course, someone else can copy my signature, trying to make it look as if what they write was written by me. But for a particular piece of writing to be an authentic signature of mine, the thing has to be generated by me personally. I think it is helpful to bear in mind this aspect of the notion of the ownership of a signature, when we consider a certain complexity in the notion of the ownership of a thought—I mean, an occurrent, episodic [End Page 35] thought. There are, I am saying, two strands in the ordinary notion of the ownership of a thought, which we do not ordinarily have any reason to separate. First, there is the notion of the person who generated that particular thought, which we might think of on the model of the person who inscribed a particular signature. Of course, in generating a particular token thought, you may be subject to all sorts of influences. Perhaps your thought is derivative, largely shaped by others. Perhaps your thoughts are sometimes simply echoes of the things other people have said. Nonetheless, when we consider how your individual token thoughts are being brought about, you play a proximal role in their formation that no one else does. To give an analogy, suppose that I am taking notes at your dictation. Then there is a sense in which the contents of my notes are entirely determined by you. But there is also a sense in which the token sentences are being generated by... (shrink)

Passivity experiences in schizophrenia are thought to be due to a failure in a neurocognitive action self-monitoring system . Drawing on the assumption that inner speech is a form of action, a recent model of auditory verbal hallucinations has proposed that AVHs can be explained by a failure in the NASS. In this article, we offer an alternative application of the NASS to AVHs, with separate mechanisms creating the emotion of self-as-agent and other-as-agent. We defend the assumption that inner speech (...) can be considered as a form of action, and show how a number of previous criticisms of applying the NASS to AVHs can be refuted. This is achieved in part through taking a Vygotskian developmental perspective on inner speech. It is suggested that more research into the nature and development of inner speech is needed to further our understanding of AVHs. (shrink)

The comparator-model, originally developed to explain motor action, has recently been invoked to explain several aspects of the self. However, in the first place it may not be used to explain a basic self-world distinction because it presupposes one. Our alternative account is based on specific systematic covariation between action and perception. Secondly, the comparator model cannot explain the feeling of ownership of thoughts. We argue—contra Frith and Campbell—that thoughts are not motor processes and therefore cannot be described by the (...) comparator-model. Rather, thoughts can be the triggering cause (intention) for actions. An alternative framework for the explanation of thought insertion in schizophrenics is presented. (shrink)

Motor imagery typically involves an experience as of moving a body part. Recent studies reveal close parallels between the constraints on motor imagery and those on actual motor performance. How are these parallels to be explained? We advance a simulative theory of motor imagery, modeled on the idea that we predict and explain the decisions of others by simulating their decision-making processes. By proposing that motor imagery is essentially off-line motor action, we explain the tendency of motor imagery to mimic (...) motor performance. We close by arguing that a simulative theory of motor imagery gives (modest) support to and illumination of the simulative theory of decision-prediction. (shrink)

What is a person, and how can a person come to know that she is a person identical to herself over time ? The article defends the view that the sense of being oneself in this sense consists in the ability to consciously affect oneself : in the memory of having affected oneself, joint to the consciousness of being able to affect oneself again. In other words, being a self requires a capacity for metacognition (control and monitoring of one's own (...) internal states). This view is compatible with the hypothesis that the self is a dynamic representation emerging out of a higher level control system, - valuation control - whose articulation with control of plans and perceptual/motor control is discussed in the context of normal and pertrubed agency. (shrink)

As fundamental researchers in the neuroethology of efference copy, we were stimulated by Grush's bold and original synthesis. In the following critique, we draw attention to ways in which it might be tested in the future, we point out an avoidable conceptual error concerning emulation that Grush seems to share with other workers in the field, and we raise questions about the neural correlates of Grush's schemata that might be probed by neurophysiologists.