Showing posts with label self awareness. Show all posts
Showing posts with label self awareness. Show all posts

Friday, January 03, 2014

Re-Conceptualizing Free Will for the 21st Century: Acting Independently with a Limited Role for Consciousness

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Yesterday I posted 5 scientific reasons to believe in free will, an article by Steven Handel at The Emotion Machine. But I wasn't content to stop there, so I also added in the excellent research of Dr. Jeffrey Schwartz and his work with self-directed neuroplasticity with those who have Obsessive Compulsive Disorder (OCD).

His work there is the best evidence for free will I have seen.

In this recent article from Frontiers in Psychology, Gregory Bonn proposes a modified version of free will that allows us to act independently with a limited role for consciousness. His model is not essentially different than my own - we have partial free will. Where we differ is in my conviction that free will can be increased through conscious, directed awareness of the automaticity of thoughts and feelings.

In reviewing the neuroscientific data against free will, Bonn sites the early work of Libet and then more recent functional magnetic resonance imaging:
Libet showed that readiness potentials or neural indications of an impulse to act were evident in participants' brains well before they reported any conscious intention to act. The conscious awareness of an intention to act in these experiments apparently came into being several 100 ms after the action had been set in motion within the brain. More recently, functional magnetic resonance imaging studies (e.g., Soon et al., 2008) have detected neural correlates of an intention to act many seconds before conscious awareness of that intention is reported. Conscious awareness of an impulse to act, thus, seems to be a neurological afterthought to the impulse itself.
He begins his discussion by defining terms, starting with free will and the position he takes in this paper.
The point of this discussion is to present psychological evidence pointing to the possibility of individual humans behaving in novel and creative ways, albeit within the constraints of whatever context they live in. The human brain, it is presumed, can only process information that it is exposed to. The argument here is that human brain functions allow for given sets of information to be combined in novel or creative ways, and furthermore, the integrative conceptions created through these processes can be used to direct action.
He then defines consciousness, an essential element of free will.
In most discussions of free will, the term consciousness refers to this type of narrative self-awareness it is used here in the same way, although it is with the assumption that the individual experiences and interacts with his surroundings on multiple levels, only some of which are accessible to conscious self-report (e.g., Morin, 2006 ).

From there he moves into memory issues and offers his definition of free will, as well as related topics, especially the role of the default mode network in all of this. Here is the crucial passage:
I have argued here for a broader conception of free will which is compatible with current neuroscientific understanding. This model is broadly outlined in Figure 1: Essentially, according to this model, the individual can generate novel concepts, translate those concepts into goals, and initiate and monitor activity toward achieving those goals. The model consists of two feedback loops which are largely anticorrelated. The first loop is made up of the default network and memory systems: The default network extracts elements of stored information from memory systems, integrates and combines information in various ways, and feeds the results back into memory. The second loop involves the executive control and motor networks: Executive regions establish and update goal priorities, while initiating and monitoring motor activities according to environmental feedback. These two loops are linked via a feed forward connection from the default network to the executive control network (e.g., Gerlach et al., 2011) which allows for output from simulations occurring within the default network to be uploaded into the executive control network and incorporated into the creation and maintenance of externally directed goals.
And this:
Though preliminary, this model provides an outline of how a practical form of free will, independently generated and controlled activity, can exist and be consistent with current findings from psychology and neuroscience. Those who adhere to particular definitions of “free will” could certainly take issue with these arguments. However, if one accepts that free will can exist in degrees limited by a person's knowledge and experiences; and, that decisions do not need to be entirely conscious in order to be owned by the individual. Then, I believe there is evidence to posit a level of will and independence within the person. Individuals can integrate information creatively to conceptualize multiple different scenarios or goals; they can choose between options; they can act according to goals; they can abort actions if they do not match current goal sets; and they can incorporate and integrate information from ongoing feedback into subsequent simulations and decisions.
This is well worth the read for those interested in this ttopic

Full Citation: 
Bonn, GB. (2013, Dec 9). Re-conceptualizing free will for the 21st century: acting independently with a limited role for consciousness. Frontiers in Theoretical and Philosophical Psychology; 4:920. doi: 10.3389/fpsyg.2013.00920

Re-conceptualizing free will for the 21st century: Acting independently with a limited role for consciousness

Gregory B. Bonn
  • Jeffrey Cheah School of Medicine and Health Sciences, Monash University, Bandar Sunway, Petaling Jaya, Malaysia

Abstract


This paper examines the concept of free will, or independent action, in light of recent research in psychology and neuroscience. Reviewing findings in memory, prospection, and mental simulation, as well as the neurological mechanisms underlying behavioral control, planning, and integration, it is suggested in accord with previous arguments (e.g., Wegner, 2003; Harris, 2012) that a folk conception of free will as entirely conscious control over behavior should be rejected. However, it is argued that, when taken together, these findings can also support an alternative conception of free will. The constructive nature of memory and an integrative “default network” provide the means for novel and creative combinations of information, such as the imagining of counterfactual scenarios and alternative courses of action. Considering recent findings of extensive functional connections between these systems and those that subsume motor control and goal maintenance, it is argued that individuals have the capability of producing novel ideas and translating them into actionable goals. Although most of these processes take place beneath conscious awareness, it is argued that they are unique to the individual and thus, can be considered a form of independent control over behavior, or free will.

Introduction


An identifying characteristic of human experience is a distinct, intuitive sense of volition. An inner voice existing within each of us insists that our actions result from personal will, telling us that we consciously choose our actions and rationally guide ourselves through life. Although intuitively satisfying, this notion has, deservedly, been the subject of much debate over the years. Recently, as neuroscience and psychology have expanded our understanding of the mind, a number of eminent scholars in these fields have provided evidence that contradicts such intuitive conceptions (e.g., Libet, 1985; Wegner, 2002; Wilson, 2002) leading some to argue that the notion of free will should be discarded entirely (e.g., Harris, 2012). Here I will argue that, although recent evidence does justify rejecting the idea that humans possess entirely conscious, reasoned self-control; if one moves away from simplistic notions of consciousness and its role in human decision making, findings from several areas, when taken together, suggest an alternative conception of free will: Humans can possess levels of autonomy even if the processes involved are not entirely accessible to conscious reason. This argument consists of several major components: In sections The Problem with Memory: Looking Backwards or Forwards? through Novel Conceptions I review evidence from multiple lines of research for novelty or creativity in human thought. Sections The Problem with Conscious Will and Why Consciousness? discuss findings regarding the limitations of conscious awareness as well as its potential value. Sections Internal Control of Behavior and Translating Simulations into Goals present evidence for the internal control of behavior as well as for functional connections between this control system and the systems involved with creative processing and counter-factual thinking. Finally, in sections Modeling Volitional Processes and Free Will with Limited Consciousness Awareness, I suggest a model for understanding how these systems interact and a more practically defensible model of free will: The creative integration of conceptual elements into novel, counter-factual simulations, and the use of these generative processes to guide behavior.
 

Scope and Limitations


The terms free will and consciousness both mean many things to many different people. For this reason it is important to first clarify some of the underlying assumptions that drive this argument. After establishing the gist of how these terms are used, as well as the intention of this paper, the line of thinking that follows should be clearer.



What is Meant by Free Will?


This paper is not meant as a philosophical treatise. As such, it does not address the more metaphysical issues, such as determinism, often invoked in free will debates. The point of this discussion is to present psychological evidence pointing to the possibility of individual humans behaving in novel and creative ways, albeit within the constraints of whatever context they live in. The human brain, it is presumed, can only process information that it is exposed to. The argument here is that human brain functions allow for given sets of information to be combined in novel or creative ways, and furthermore, the integrative conceptions created through these processes can be used to direct action.

Another point is that, although philosophers have significantly more nuanced ways of understanding the term, psychologists tend to operationalize free will by relating it to self-report (e.g., Libet et al., 1983; Wegner, 2008) which requires a form of self-reflective conscious awareness. The implicit condition is that one must be able to report upon all the processes leading up to a decision or behavior in order for it to be “free,” and conversely, if my brain generates an idea or initiates an action without my conscious awareness it is somehow not “me” doing the thinking or acting. The conception of freedom argued for here, on the other hand, merely requires that thoughts and resulting actions be novel and internally generated, that they result from a combination of experiences and characteristics which is unique to the individual. Unconscious, or implicit, processes are, in this view, essential components of how an individual processes information: Regardless of whether a particular process can be observed and narrated by the conscious, self-aware part of the brain, it can still make unique and important contributions toward thought and action, and thus, to the independence of the individual. The arguments here, thus, specifically reject the simplistic notion that free will requires complete conscious awareness of the processes involved.



What is Meant by Consciousness?


A separate, but closely related point should also be made about the term “consciousness” which is used rather haphazardly by both scientists and laypersons to refer to a range of different phenomena (Chalmers, 1995). A basic conception of consciousness is experiential awareness or alertness, which is defined in contrast to unconsciousness (e.g., being awake as opposed to being in a deep sleep or a coma). Consciousness, from this viewpoint, can exist on many levels and possess varying degrees of complexity, all of which are simply characterized by the presence of subjective or phenomenal experience (Velmans, 2009). For example, every person experiences many degrees of alertness, a variety of emotions, as well as many other subjective phenomena over the course of a given day. There is no one conscious state that can be defined, there are rather, many overlapping, but differentiable states, some simple and some quite complex; some describable and some inscrutable. By this definition, although their subjective “experience” would vary tremendously (see, for example, Nagel, 1974) most forms of animal life as well as very small children would possess consciousness in some form. Tononi's (2008) conceptualization of consciousness as integrated information is suggestive in this regard. By contrast, studies that are commonly cited as evidence against conscious free will (e.g., Libet et al., 1983; Wegner, 2003) tend to operationalize consciousness as an awareness of mental processes which is measured through self-report: Participants are asked to describe aspects of their experience after performing certain tasks. It should be obvious that, although they are often conflated, these conceptions of consciousness are far from equivalent. The latter is more accurately a form of metacognition (i.e., “thinking about thought”), or self-consciousness, which is a small, so far as we know distinctively human, subset of the former (e.g., Rochat, 2003). Nevertheless, since in most discussions of free will, the term consciousness refers to this type of narrative self-awareness it is used here in the same way, although it is with the assumption that the individual experiences and interacts with his surroundings on multiple levels, only some of which are accessible to conscious self-report (e.g., Morin, 2006). For the purpose of this discussion, internal processes belong to the individual regardless of where they fall on any continuum of consciousness to unconsciousness.
 

Memory, Prospection, and Creativity

Several areas of research have recently converged on a conception of memory as constructive, with the ability to combine elements of different remembered events in an integrative fashion. Evidence for processes that extract and recombine elements of multiple representations in generative, potentially novel, ways is discussed throughout the next six sections.


The Problem with Memory: Looking Backwards or Forwards?


Research has, over the years, pointed toward inaccuracies in the functioning of human memory (e.g., Schacter, 1999; Moscovitch et al., 2006; Addis et al., 2007). Remembering, it has been shown, is more of a creative, constructive process than the precise recall of past events. People, for example, often remember things that never happened (Roediger and McDermott, 1995), and conflate different episodes with each other, combining bits and pieces of various events into a single recalled instance (e.g., Tulving, 2002; Schacter and Addis, 2007a). Similarly, memories for specific events apparently change with each recollection, often incorporating current information with past impressions (Bridge and Paller, 2012). Having experienced problems stemming from such inaccuracies, it is not surprising that most people interpret such inaccuracies as “bugs,” or errors, in a memory system which should, intuitively, provide accurate information about the past.

Recent interpretations of such phenomena, however, (Dudai and Carruthers, 2005; Schacter and Addis, 2007b) speculate that the lack of factual accuracy in our recollections may instead be the signature of a system that evolved, not to store accurate representations of the past, but instead, to provide a means of flexibly imagining the future, as well as conceiving of other hypothetical scenarios. Surviving in the real world does not depend upon accurate recall of every past detail as much as an ability to predict future contingencies (Schacter et al., 2008). A system that can integrate details of multiple past events and is more sensitive to broad patterns and associations rather than accurately representing minutia would be well suited to this purpose.

The idea that memory systems play an important role in the creation of counter-factual scenarios, or formulating mental simulations, is supported by findings from several areas. Neurological studies find considerable overlap of brain systems used in memory and simulation (e.g., Buckner, 2010). Research on Construal Level Theory (Trope and Liberman, 2010) has identified similar patterns in how we conceptualize the past and the future. Also, studies of prospection, or predicting the future (Gilbert, 2006; Gilbert and Wilson, 2007), demonstrate that emotions and memory play an important role in imagining the future. These points are briefly reviewed in the following sections.


Neurobiology of Memory and Prospection

Patients with memory deficits have, for some time, been observed to have difficulty planning for and imagining the future (Tulving et al., 1988; Hassabis et al., 2007). This led to some early speculation about a relationship between memory and prospection (e.g., Fuster, 1989) which has only recently been confirmed by functional imaging studies (Addis et al., 2009). Growing evidence points to a core network of brain regions involved in remembering the past and imagining the future, as well as other forms of mental simulation (Arzy et al., 2009; Spreng and Grady, 2010). In broad terms, tasks related to “mental time travel” (i.e., remembering the past and predicting the future) incorporate memory systems in the medial temporal lobes, the lateral parietal lobes and the hippocampal formation (Wheeler and Buckner, 2004), in addition to areas in the medial frontal lobes which are involved in perspective taking and theory of mind, or understanding others' mental states (Gallagher and Frith, 2003). It seems that many forms of self-projection; imagining the past and future, navigation (imagining the self in different physical locations) and theory of mind (taking the perspective of other people) depend on this same core network of memory-related brain areas (Buckner and Carroll, 2007).


The Default Network: Integrating Information While at Rest

Particularly relevant for this discussion are findings (e.g., Buckner et al., 2008) noting increased activity in this core network of brain regions during periods of undirected mental function, or passive states—hence its common designation as the “default network.” This default network is broadly associated with many forms of stimulus-independent thinking or internally focused cognition (Spreng and Grady, 2010): Mind-wandering, daydreaming, imagining the future, reminiscing about the past, as well as thinking about the cognitive states of others are all subsumed within its functions (e.g., Hassabis and Maguire, 2007; Schacter et al., 2008). When the brain is not occupied with processing external stimuli, activity reverts to this area where stored impressions are consolidated and reorganized (Buckner, 2010). The default network seems to facilitate the internal experience of scenarios and perspectives that transcend simple recall, and it seems to do so automatically through making connections between, or recombining, elements of multiple memory traces.


Abstraction and the Extraction of Gist Elements

Evidence of how this reworking of stored memories operates can be seen in Trope and Liberman's (2010) research on mental representations (summarized as Construal Level Theory). They have shown that mental representations of objects and experience become reconstructed in different ways at various levels of abstraction. “Psychological distance,” for example spatial, temporal, or social separation, between a person and an object leads to representations of differing resolution. Objects, people, and situations that are imagined to be distant are represented with less resolution; their conceptions become more abstract and essentialized (Liberman et al., 2002). A chair, for example, could be imagined as a specific object one is sitting on now, or imagining various future or past scenarios representations can take on numerous forms. For example, imagining a chair in an office, a living room, a restaurant, a car, or a spaceship can result in many different images. All that remains constant is the essential quality of affording sitting (see Gibson, 1977). The mind changes how it represents objects based upon the imagined context (e.g., Smith, 1998), adding or removing non-essential elements to facilitate the formation of a sensible scene. Complementing the research on memory and the default network, Construal Level Theory illustrates how gist elements from numerous impressions can be combined to create mental simulations placing the self and others in various situations and contexts (Wakslak et al., 2008).


Emotions, Memory, and Imagining the Future

Similarly, the integration and fuzzy processing that seems to occur in the default network is evident in Gilbert's (2006) writings about prospection. Emotional aspects of memories and current states influence mental simulations in important ways. Current emotional states, for example, color our emotional feelings about future events (Gilbert and Wilson, 2007); so, for example, if we are in a good mood when imagining a future date we are more likely to imagine it going well. Also, as memories tend to be skewed toward emotional peaks and valleys (Morewedge et al., 2005); simulations become “over emotionalized.” They tend to focus on brief highlights (or lowlights): Thinking about a future trip to an amusement park, for example, we might just remember the thrill of riding a roller coaster, and the pleasure of eating ice cream from past visits; not so much the monotony of waiting in long lines.

Gilbert (2006) also points out that memories and predictions of the future are strongly influenced by cultural scripts or “memes” (e.g., Blackmore, 2000; Bonn and Tafarodi, 2013). Our memories of the past, as well as imaginings of the future, are given meaning and form by the narratives that predominate in our cultures. The stories that we observe and hear being told from day-to-day shape our expectations and evaluations of our own lives, leading us to reshape the way we remember experiences over time (Klaaren et al., 1994). Memories (and in turn our expectations about the future) get rewritten each time they are accessed. Thus, over time the way we remember our past and what we expect in the future tends to fall in line with the narrative zeitgeist.


Novel Conceptions

Evidence, thus, supports the notion that as processing becomes removed from current surroundings representations change in nature: Details fall away while meaning, feelings, and connecting relationships become more important. Elements of different scenarios, when stripped of context, mingle with one another, potentially combining in ways many steps removed from actual experience.

Regardless of where such connections appear on a spectrum of conscious awareness, the integrative systems that seem to center around the default network allow for a great deal of flexibility in imagining and simulating possible realities. Although such simulations can be deeply flawed in the sense of being factually inaccurate and susceptible to bias, they are unique to the individual in that they are based upon that person's specific set of experiences. Each mind has a specific store of knowledge to which it can “add value” by integrating that information in qualitatively new ways (e.g., Tononi, 2008). New formulations of knowledge, in theory, can subsequently be fed back into the processing system and form the bases for new phantasies (e.g., Kashima et al., 2007). Simulations thus, have the potential to build upon each other through a process of scaffolding, feeding back into memory and integrating with each other iteratively over time.

Buckner (2010) actually takes the potential for originality one step further by arguing that, not only can we extract and combine elemental properties of information in creative ways, but random variations in neural firings would almost certainly play a part in the flexibility of this sort of system. He observes that seemingly random properties of neural systems are observable in nature. Aronov et al. (2008), for example, has identified a specific brain structure in finches that seems to relate to random song patterns. Cisek and Kalaska (2005) observed apparently random variations in neural firing influencing behavioral choice in monkeys. Relatedly, Bim (2012) has noted that physiological noise, such as respiratory and cardiac fluctuations, can influence resting functional connectivity in the brain. Thus, intrinsic properties of neural systems combined with environmental variation could allow for novel leaps in connectivity or new combinatorial patterns. Again, this is not an argument for conscious control over how the mind produces concepts, but for a capacity of originality, generativity, or creativity, in how it processes information.



Consciousness: Limitations and Capabilities

The Problem with Conscious Will

The studies most commonly cited in neuropsychological arguments against the existence of free will began with a series of experiments conducted by Benjamin Libet and his colleagues (1983; 1985). Libet showed that readiness potentials or neural indications of an impulse to act were evident in participants' brains well before they reported any conscious intention to act. The conscious awareness of an intention to act in these experiments apparently came into being several 100 ms after the action had been set in motion within the brain. More recently, functional magnetic resonance imaging studies (e.g., Soon et al., 2008) have detected neural correlates of an intention to act many seconds before conscious awareness of that intention is reported. Conscious awareness of an impulse to act, thus, seems to be a neurological afterthought to the impulse itself.

Along similar lines, Wegner (2003) has collected extensive evidence indicating that, in many cases, our experience of conscious will is misleading. In some cases the feeling of causing or of willing an action does not exist after we have performed it (e.g., Geschwind et al., 1995) and in other cases we can be led to believe that we caused an action that we, in fact, did not (Ansfield and Wegner, 1996; Wegner and Wheatley, 1999). Wegner theorizes that the sense of having willed an action is inferred from various indicators: If we think a thought just prior to an action; the action is consistent with our thought; and there is no other obvious cause of the action; then, we tend to infer that we performed the action (Wegner, 2003). Even more, once we have inferred responsibility for an action we tend to rewrite our perceptions so that they are more consistent with this sense of authorship. Evidence shows, for example, that we estimate the gap between thought and action to be smaller for actions that we believe we have willed and longer for actions we do not feel responsible for (Ebert and Wegner, 2011). Again, the gist of these findings is that our feeling of having consciously willed an act is illusory in many ways. It seems that the conscious awareness of intention that we place so much weight upon, that we naively think of as causal, is, in fact, a narrative construction that is formed well after the train of causation has been set in motion.

What Wegner, Libet, and others have shown clearly is that the narrative awareness of a will to act arises after the actual impulse to perform a certain action. This does not mean, however, that the action is not owned by the person. It merely shows that action is not initiated by the narrative self. Only if our definition of the self is limited to narrative capability can we say that the person didn't initiate the action. One must acknowledge, based on the evidence, that the stories we create about our actions are misleading. They are subjective impressions, not factual accounts of all the processes involved. The argument can still be made, however, that the individual (i.e., the person in the broader, not necessarily self-conscious, sense) may initiate or control behavior on other, less explicit, levels.
Why Consciousness?

Libet (1999) himself pointed out that even if the conscious impression of will is merely corollary to and not the direct cause of an action it still occurs enough in advance of the action to allow for a conscious “veto” or a decision to not perform the action. Such late inhibitory decisions apparently involve an area in the frontomedian cortex (Brass and Haggard, 2007) and involve perceptual feedback (Moore et al., 2009). Consciousness, in this way, seems to have the potential to play some role in self-monitoring processes (Kuhn and Brass, 2009). Although we are not consciously aware of what is going on at every stage of the chain of neural events leading to action, there is room for a degree of conscious involvement if only to pull the emergency brake before it is too late. Thus, although it may not be the initial source of motivations and behavioral impulses, the part of the mind that is self-reflective; that can envision the self in causal and narrative contexts, may serve important monitoring and control functions.

Even Wegner, who has tirelessly argued that the folk understanding of conscious will is an illusion, has suggested that such an illusion probably serves some social purpose (Wegner, 2008). Being able to observe our behavior and its results in context, he suggests, allows individuals to better fit into complex social arrangements. Although illusory, the perspective of agency allows the brain to fine tune its behavioral impulses. “It tells us what we can and cannot do (Wegner, 2008; p. 241),” and further, the illusion of conscious will “makes behavior more open to modification (Wegner, 2008; p. 243).” So, for Wegner, the fact that conscious will is largely illusory does not completely rule out self-reflective capabilities from having some effect on behavior.

Consciousness may play an important role in monitoring the self and its behavior within contexts. Consciousness, in the sense of self-reflection, is closely entwined with the creation of narrative meaning (McAdams, 2008). Narrative meaning making involves processes such as conceptualizing the self in relation to higher-order or longer-term goals and social rules as well as imagining the consequences of actions and the reactions of others to those actions. This is all critical to understanding how the self relates to the surrounding world, and especially to integrating behavior with complex social contexts (Cozolino, 2002; Baumeister, 2008; Rochat, 2009). A monitoring function for the conscious self would, in theory, track behavioral impulses and their potential results, looking for conflicts between the actor and his longer term goals as they arise, with the potential for triggering inhibitory functions at various times. Consciousness, in this view, influences behavior by providing broad contextual input and inhibitory feedback into a complex planning system. Behavioral impulses, however, would be produced by mechanisms that are outside of direct conscious control. Consciousness per se is most useful because it can monitor behaviors, goals, and the changing environment in real-time watching for potential conflicts. The bulk of processing, however, must take place in other complex systems that operate largely beneath the surface. Consciousness seems most important for providing up-to-the-minute contextual integration and feedback to other systems. Self-reflective monitoring facilitates the fine-tuning of impulses and behaviors, and inhibitory control, necessary for high-level integration with dynamic physical and social environments.


Control and Planning of Behavior

Strictly conscious control over behavior seems to be ruled out by our improved understanding of the mind. Does this mean, however, that a person is not in control of their behavior? Again, keeping in mind a broad definition of the “person” as including both conscious and unconscious elements, recent discoveries can shed light on this issue. First, there is a separate motor control network dedicated to internally generated, voluntary, goal oriented behaviors as contrasted with externally-triggered and more habitual behaviors. Second, there appear to be connections between the default network, where novel ideas and counterfactual scenarios are produced, and this goal-oriented control network that allows for the internal generation of action.


Internal Control of Behavior

Two major sources provide activating input to the primary motor cortex, which is the initiator of muscle movement (Haggard, 2008). The first motor control system runs from the sensory cortices to the primary motor region via the pre-motor area: Activity in these areas relates to stimulus-driven, or reflexive, responses to sensory input as well as to habitual behaviors such as grasping, eating, and walking which are performed largely unconsciously (Prabhu et al., 2007). The second motor system involves multiple regions, including the cingulate, frontal cortices, and basal ganglia, which connect to the primary motor cortex via the pre-supplementary and supplementary motor areas. Behaviors that require planning and goal maintenance engage some or all of this system (Daw et al., 2006; Hirosaka, 2008). Processes mediated by pre-supplementary motor area (preSMA) connections generally allow for the flexible, online integration of goal states, decisions, and action priorities with feedback from the environment. Imaging studies, for example, show that the preSMA is consistently involved in task-focused activities and situations that require the preferential selection of certain behaviors over others (Nachev et al., 2007). Importantly, patients with damage to the preSMA are deficient in their ability to prioritize behaviors and suppress automatic behaviors (Pacherie, 2007): They might, for example, impulsively grasp, eat, or drink without reporting the intention or desire to do so (Della Salla et al., 1991), suggesting that the preSMA plays a role in inhibiting the habitual behaviors governed by the first motor control system.

This second motor control system plays a crucial role in tasks related to goals and decision making. The preSMA, along with the frontopolar cortex and the rostral cingulate, is active in tasks requiring decisions between multiple options, such as choosing between right or left hand key presses (Ammon and Gandevia, 2007; Mueller et al., 2007). The frontopolar cortex is also involved in maintaining goal states such as suppressing responses to immediate environmental demands (Koechlin and Hyafil, 2007; Dreher et al., 2008) and, along with the anterior cingulate (ACC), is seemingly involved in the production of goal-directed action sequences (Holroyd and Yeung, 2012). The ACC, through the preSMA, also seems capable of selecting and initiating action in the absence of external prompts, as well as monitoring and adjusting those actions in response to feedback (Rowe et al., 2010; Zhang et al., 2012). All told, there are extensive findings indicating that the preSMA is involved in interfacing multiple goal and decision-related subsystems with the primary motor cortex.

Most complex behaviors would involve an integration of these two motor systems, with the more automatic system triggering the basic movements and the decision and goal related system throwing in guidance and inhibitory impulses at important junctures. Although these relationships need further clarification, the pathways mediated by the supplementary and pre-supplementary motor areas do seem to allow for basic internally guided choice, selective inhibition, and “volition-like” control of behavior (Haggard, 2008), though probably not complex decision-making or reasoning (e.g., Koechlin and Hyafil, 2007). The next section will propose that these systems are capable of interfacing with the default network during planning tasks. In this way, output from integrative processes taking place in the default network could be incorporated into goal formation and behavioral control.


Translating Simulations into Goals

To this point we have established two important concepts. First, processing in the default network allows humans to create novel combinations of information. Information stored in memory is broken down to elemental form and connections made between elements during times of reduced sensory input. This allows for patterns and relationships among multiple impressions to be extracted and for the flexible generation of counterfactual simulations. Second, faculties exist for internally maintained goals to exert flexible control over behavior. Humans can replace automatic, reflexive behaviors with internally guided, goal-directed action.

Default network functioning, by definition, is most active when the external attention necessary for goal-oriented functioning is absent. Thus, the systems that produce novel ideas and those that maintain goals are usually thought of as contradictory, or negatively correlated (e.g., Fox et al., 2005; Carhart-Harris and Friston, 2010). Free will as it is conceptualized here, however, would require an interface between these two levels of operations. For behaviors to be called free, or independently generated, they would need to result not just from the complex training processes that reside within the goal maintenance system: They would need to incorporate elements that are unique to the individual; that are novel and creative, as well. The brain would need to be able to translate the abstract simulations and integrated information produced by the default network into actionable goals.

Recently, Spreng et al. (2010) found that tasks in which participants made goal-related plans activated default network regions as well as regions commonly associated with cognitive control (i.e., areas of the frontal cortex and the ACC). Similarly, other recent studies (Gerlach et al., 2011; Spreng and Schacter, 2012) have found that solving imagined future problems involved default network areas as well as control network areas. In particular, the dorsolateral prefrontal cortex, which is central to rule acquisition and goal maintenance functions (Badre and D'Esposito, 2009; Badre et al., 2009; Packer and Cunningham, 2009) has been implicated, along with default network regions, in planning tasks. Gerlach et al. (2011) have also found functional connections between the posterior cingulate cortex, which is thought to be the nexus of the default network, and the dorsolateral prefrontal cortex. The default network, then, is seemingly able to interface with goal maintenance and cognitive control functions when engaged in problem solving and future planning. This suggests that the generative capacity of the default network; the ability to extract elements of diverse memories and impressions and integrate them in novel ways, could be used to create concrete, actionable goals.
 

Reconceptualizing Free Will

Modeling Volitional Processes

Thus, although the folk conception of free will as entirely conscious self-control seems to be dead in the water (e.g., Wegner, 2008; Harris, 2012), I have argued here for a broader conception of free will which is compatible with current neuroscientific understanding. This model is broadly outlined in Figure 1: Essentially, according to this model, the individual can generate novel concepts, translate those concepts into goals, and initiate and monitor activity toward achieving those goals. The model consists of two feedback loops which are largely anticorrelated. The first loop is made up of the default network and memory systems: The default network extracts elements of stored information from memory systems, integrates and combines information in various ways, and feeds the results back into memory. The second loop involves the executive control and motor networks: Executive regions establish and update goal priorities, while initiating and monitoring motor activities according to environmental feedback. These two loops are linked via a feed forward connection from the default network to the executive control network (e.g., Gerlach et al., 2011) which allows for output from simulations occurring within the default network to be uploaded into the executive control network and incorporated into the creation and maintenance of externally directed goals. Additional information is continually fed back into the memory and control systems through sensory input from the environment. Each person's activities lead through their observed effect on the environment to a unique store of information in the individual memory system. The many impressions; sensory, emotional, or otherwise, that the individual has in memory are available to the default network during times of reduced input. During such periods, elements or traces of different memories are combined together in various ways with the results then stored and available for further processing.

FIGURE 1  
http://c431376.r76.cf2.rackcdn.com/71195/fpsyg-04-00920-HTML/image_m/fpsyg-04-00920-g001.jpg

Figure 1. Model showing interconnections among systems for memory, mental simulations, behavioral control, and conscious awareness.
Both loops are accessible to a limited degree by conscious awareness or self-reflective abilities and receive some feedback from this conscious level. Conscious awareness is mostly important here for online monitoring and the incorporation of current contextual information. Although most processing occurs beneath conscious awareness, the ability to direct attention both inwards and outwards could make conscious awareness especially useful for monitoring and minimizing conflicts between actions, intentions, and real-time, current context. In the case of the control/motor network loop, conscious awareness also possesses some veto-like inhibitory powers: It can interfere with certain impulses before action is initiated (e.g., Libet, 1999). In the context of the default network, conscious monitoring could integrate current contextual information with ongoing simulations, perhaps providing reality checking functions which keep simulations more in line with the external environment. In both systems conscious awareness need not be directly causal, but just provide monitoring and additional real time information as feedback into the system.

Though preliminary, this model provides an outline of how a practical form of free will, independently generated and controlled activity, can exist and be consistent with current findings from psychology and neuroscience. Those who adhere to particular definitions of “free will” could certainly take issue with these arguments. However, if one accepts that free will can exist in degrees limited by a person's knowledge and experiences; and, that decisions do not need to be entirely conscious in order to be owned by the individual. Then, I believe there is evidence to posit a level of will and independence within the person. Individuals can integrate information creatively to conceptualize multiple different scenarios or goals; they can choose between options; they can act according to goals; they can abort actions if they do not match current goal sets; and they can incorporate and integrate information from ongoing feedback into subsequent simulations and decisions.

Free Will with Limited Consciousness Awareness

As I have discussed, the role that consciousness, as it is commonly conceptualized, plays in these processes is limited. It is not, however, non-existent. There is a place in this model for conscious monitoring of simulations and goal states, the integration of sensory information with ongoing internal processes, and related inhibitory control. The vast majority of processing in this model does, however, take place beneath the level of conscious awareness and self-report. If one considers the degree to which unconscious processes are involved in every action that we undertake, this should become far less of a concern. For example, consider everyday acts like walking from one place to another, or speaking a sentence. These are incredibly complex behaviors requiring the coordinated operations of many thousands of neurons and muscles simultaneously. When we perform such acts we are not aware of exactly how we balance our bodies or shape our mouth and tongue at any particular moment. Our bodies just perform as we expect them to (normally) and we report via our conscious awareness a summary of what we did or what we intended to do: We just think “I walked to the café and ordered a coffee,” for example. We don't notice exactly how every muscle moved along the way, where we placed our feet, or how we formed our words. Most people, however, would not claim a lack of control over their bodies. It is not irrational to believe that, yes; I took a walk and ordered coffee.

Cognitive psychology has shown over the years that large portions of mental processing take place beneath the level of consciousness awareness (e.g., Kahneman, 2011; Kihlstrom, 2013). Much of our mental processing involves energy- and time-saving shortcuts, and much of our behavior is, for similar reasons, habitual. This does not necessarily mean, however, that consciousness is entirely left out of the picture, but certainly the conception that we are in complete conscious control (or that we always behave rationally) has been proven to be illusory. What I have argued here is that if we abandon the ideas that human will needs to be completely explicit, and that conscious awareness and control of every process is required for an individual to be a decision maker, it is possible to see evidence of originality, individuality, and creative processes, as well as cognitive control, in the way that each person thinks and behaves. This type of individuality, I believe, can be called free will.


Conflict of Interest Statement

The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
 

Acknowledgments

This work was funded by a Fundamental Research Grant (FRGS) from the Ministry of Education, Malaysia.


References available at the Frontiers site.

Friday, November 01, 2013

The Multiplicity of Consciousness and the Emergence of the Self - Gerard O’Brien and Jon Opie

 

This article by Gerard O’Brien and Jon Opie appeared in The Self in Neuroscience and Psychiatry (2003). This is a draft version of the article dated 2000, but it is an excellent and interesting read - and their theory on self and consciousness is not dissimilar to that of Hubert Hermans' Dialogical Self Theory (see also Dialogical Self Theory: Positioning and Counter-Positioning in a Globalizing Society [2012] or Handbook of Dialogical Self Theory [2013]).

The Multiplicity of Consciousness and the Emergence of the Self

Gerard O’Brien and Jon Opie

Department of Philosophy, University of Adelaide, South Australia 5005
gerard.obrien@adelaide.edu.au
http://arts.adelaide.edu.au/Philosophy/gobrien.htm
jon.opie@adelaide.edu.au
http://arts.adelaide.edu.au/Philosophy/jopie.htm

In A. S. David & T. Kircher (eds.) The Self in Neuroscience and Psychiatry, Cambridge University Press, 2003. [Draft @ October 2000]

Abstract

One of the most striking manifestations of schizophrenia is thought insertion. People suffering from this delusion believe they are not the author of thoughts which they nevertheless own as experiences. It seems that a person‘s sense of agency and their sense of the boundary between mind and world can come apart. Schizophrenia thus vividly demonstrates that self awareness is a complex construction of the brain. This point is widely appreciated. What is not so widely appreciated is how radically schizophrenia challenges our assumptions about the nature of the self. Most theorists endorse the traditional doctrine of the unity of consciousness, according to which a normal human brain generates a single consciousness at any instant in time. In this paper we argue that phenomenal consciousness at each instant is actually a multiplicity: an aggregate of phenomenal elements, each of which is the product of a distinct consciousness-making mechanism in the brain. We then consider how certain aspects of self might emerge from this manifold substrate, and speculate about the origin of thought insertion.


1. Introduction


Schizophrenia is a complex and heterogeneous disease, incorporating at least three distinct subsyndromes: psycho-motor poverty (poverty of speech, lack of spontaneous movement, blunting of affect), disorganisation (inappropriate affect, disturbances of the form of thought), and reality distortion (Liddle 1987, Johnstone 1991). The reality distortion syndrome encompasses the so called "positive" symptoms of schizophrenia, which include auditory hallucinations, delusions of persecution and delusions of reference. Of these "thought insertion" is arguably the most bizarre. People suffering from this delusion believe that some of the thoughts they experience are not their own:
I look out the window and I think that the garden looks nice and the grass looks cool, but the thoughts of Eammon Andrews come into my mind… He treats my mind like a screen and flashes his thoughts onto it like you flash a picture. (Reported by Mellors 1970, p.17)
To get a feel for how bizarre this is, contrast thought insertion with the experience of hearing voices. The standard explanation of such auditory hallucinations is that the voice the schizophrenic ―hears‖ is actually inner speech which has been mis-identified as emanating from someone else. The error, in this case, is comprehensible: we‘ve all had the experience of being uncertain whether the noise we just heard was real or imagined.[1] Thought insertion, on the other hand, is not a case of mistaking an introspection for a perception. Those who suffer with this delusion are quite aware that the thought has arisen in their own minds. But despite this recognition they still disown it: the thought doesn‘t have any "my-ness" attached to it.

Given this symptomatology, it is not surprising that the working presupposition of most current research in this area (and the organising theme of the current volume) is that schizophrenia is, at least in its delusional form, a disease of the self. Despite this focus, what has not been sufficiently appreciated is how radically schizophrenia challenges our assumptions about the nature of the self. Crucial to being a human self is the possession of a certain sort of inner life, one which encompasses a distinction between one‘s own thoughts, feelings, and actions, and the world in which one is embedded. Conventional wisdom has it that this kind of self-consciousness is a unitary faculty, and, moreover, one that is of a piece with phenomenal consciousness in general. However, by demonstrating that it is possible to be aware of the boundaries of one‘s mind without acknowledging that all of the thoughts contained therein are one‘s own, the delusion of thought insertion suggests that this traditional conception of self-consciousness actually conflates two quite distinct capacities.

The first is the brain‘s capacity to distinguish its mind from the rest of the world. This capacity produces a sense of subjectivity: an awareness that certain thoughts, perceptions and feelings comprise the mental life of a single psychological subject. The second is the brain‘s capacity to distinguish between self-initiated thoughts and actions, and mental occurrences of which it is merely the passive recipient (e.g., perceptions). This capacity produces a sense of agency: the brain‘s awareness of itself as the source of the thoughts and imaginings that occur within its boundaries. [2] Thought insertion demonstrates that these two capacities can come apart: schizophrenics afflicted with this delusion believe that they are not the agents of some of the thoughts contained within their own minds. From this perspective, schizophrenia would seem to be a disease that undermines a person‘s sense of agency, while leaving their sense of subjectivity intact.

The distinction between theses two kinds of self-awareness, and the fact that they can be selectively impaired, means that it is no longer possible to talk of our experience of self as though it were a single, monolithic entity, and hence assume that there must be a single, all-encompassing explanation which does it justice. For example, the facts that explain the brain‘s capacity to draw a distinction between its mind and the world must be different from those which explain its capacity to represent itself as a cognitive agent. Furthermore, because subjects can experience certain thoughts and yet disown any agency in respect of them, the different aspects of selfhood would appear to be achievements over and above the brain‘s capacity to manufacture individual conscious experiences. In schizophrenia, in other words, we have a vivid demonstration that the self is a complex construction of the brain that is to some degree independent of its capacity to generate consciousness.

We would go further. We believe that schizophrenia offers a unique window on the cognitive operation of the brain. It reveals a relationship between the structure of consciousness and the brain‘s cognitive machinery that is very different from the conception which has dominated our thinking for centuries. Most theorists in this area, either explicitly or implicitly, endorse the traditional doctrine of the unity of consciousness, according to which a normal (intact) human brain generates a single consciousness at any instant in time (rather than several distinct consciousnesses), and hence a single stream of consciousness over time (rather than parallel tributaries). However, what we know of schizophrenia suggests that, far from being a unity, phenomenal consciousness at each instant is actually a multiplicity: an aggregate of phenomenal elements, each of which is the product of a distinct consciousness-making mechanism in the brain. We will call this, for reasons to be explained shortly, the multi-track model of consciousness, by contrast with the single-track model that is implicit in the doctrine of the unity of consciousness.

Our aim in this paper is to make good on these claims. We begin by introducing the multi-track model of consciousness, partly by contrasting it with its more conventional (single-track) counterpart, before considering the evidence for this model. We go on to consider how some aspects of self might emerge from the distributed and manifold substrate of consciousness, and enter into some speculations as to how the failure of this emergence gives rise to the symptoms of schizophrenia.


2. The Multiplicity of Consciousness


Many if not most contemporary theorists working in the field of consciousness studies endorse the doctrine of the unity of consciousness. According to this doctrine, the intact human brain produces a single consciousness at each instant, as opposed to several distinct consciousnesses. Here we argue that this doctrine is mistaken: far from being a unity, phenomenal consciousness is actually a multiplicity. Before proceeding, however, we must provide a clearer picture of what the supposed unity of consciousness entails about the way the brain makes consciousness.

2.1 What does the unity of consciousness entail?

At the outset let us quickly dispense with a naïve, albeit influential, understanding of the unity of consciousness. Some would have it that consciousness is a unity because it is a serial stream comprising a single informational content at each moment (see, for example, Penrose 1989, p.399). Like a solo chorister, who, by virtue of the limitations of the human vocal folds, can only produce one note at a time, consciousness is taken to be single-voiced or monophonic. This reading of the unity of consciousness can hardly be sustained. Even the most casual inspection of instantaneous conscious experience shows it to contain contents drawn from a number of different modalities. Sound and vision, for example, don‘t compete for a place in awareness; both are simultaneously present. You may not be able to simultaneously react to, or focus on, disparate sources of experience, but the phenomenology they generate can certainly co-occur.

If we suppose that consciousness incorporates a number of distinct contentful elements at each instant, then it is best likened to polyphonic choral music. Musical polyphony involves two or more simultaneously active voices, such that at any moment there are a number of different notes being sounded. We think it is safe to say that most theorists regard moment by moment consciousness as informationally polyphonic. However, a question immediately arises for an advocate of the unity of consciousness: If consciousness is polyphonic, in what sense is it a unity? The unity on offer can‘t be the unity of an undifferentiated whole, because, by assumption, experience is actually a composite structure: it is assembled from numerous contentful elements that have been fused together in some way. The polyphony of consciousness entails, therefore, that any proponent of the traditional doctrine of the unity of consciousness is committed to there being a single consciousness-making mechanism or process in the brain, whose task it is to bind these different contents together into a unity. On the one hand, the task of combining multiple representational contents in a single experience must be performed by some physical mechanism or process. And on the other, if we suppose that the brain implements more than one such mechanism or process, then it must be capable of simultaneously generating more than one experience, contrary to the unity doctrine.

Given this constraint, there appear to be only two roads open to the advocate of a polyphonic, but unitary consciousness: 1) treat conscious experience as the product of a single, central neural system where informational contents must be re-presented to be made conscious, or 2) opt for a somehow unitary consciousness-making process that acts simultaneously on the brain‘s many distinct information processing sites.

A representative example of the former approach is Baars‘ "Global Workspace" model of consciousness (1988, 1997). Baars begins with the premise that the brain contains a multitude of distributed, unconscious processors all operating in parallel, each highly specialised, and all competing for access to a global workspace – a kind of central information exchange for the interaction, coordination, and control of the specialists. Such coordination and control is partly a result of restrictions on access to the global workspace. At any one time only a limited number of specialists can broadcast global messages (via the workspace), since different messages may often be contradictory. Those contents are conscious which gain access to the global workspace (perhaps as a result of a number of specialists forming a coalition and ousting their rivals) and are subsequently broadcast throughout the brain (1988, pp.73-118).

In support of this model, Baars claims there is a brain structure suited to the role of workspace, namely: the Extended Reticular-Thalamic Activating System (ERTAS), which includes the reticular formation, the thalamus, and the "diffuse thalamic projection system" (p.124). The ERTAS is particularly suited to the role of "global broadcaster," given the bidirectional projection system that it incorporates. Moreover, there is "evidence of a feedback flow from cortical modules to the ERTAS" and of global information feeding "back into its own input sources." Baars suggests that "[both] kinds of feedback may serve to strengthen and stabilize a coalition of systems that work to keep a certain content on the global workspace." That is, given the competitive nature of access to consciousness, "a circulating flow of information may be necessary to keep some contents in consciousness" (p.134).

This kind of model provides an explanation for the unity of consciousness, because the ERTAS acts as an executive composer and broadcaster. Its role is to combine a number of distinct contents hailing from different sense modalities into a single work, which it then broadcasts polyphonically. The unity of consciousness, on this story, is not imposed by the seriality of the stream of contents broadcast (as would be the case with a monophonic executive), but by virtue of there being a single broadcasting mechanism.

As to the second route available to the advocate of the unity of consciousness in the face its manifest polyphony, a number of neuroscientists have suggested that distributed time-locked neural oscillations might fit the bill. Consider, for example, Damasio‘s proposal:
The integration of multiple aspects of reality, external as well as internal, in perceptual or recalled experiences, both within each modality and across modalities, depends on the time-locked co-activation of geographically separate sites of neural activity within sensory and motor cortices, rather than on a neural transfer and integration of different representations towards rostral integration sites. The conscious experience of these co-activations depends on their simultaneous, but temporary, enhancement…against the background activity on which other activations are being played out. (1989, p.39)
Damasio here explicitly repudiates the central theatre model, and builds his account around the known parcellation and distribution of information processing in the brain. What brings content-bearing activity to consciousness is its temporary enhancement as a result of time-locked co-activation with contents coded elsewhere in the brain. Time-locking "integrates" contents coded at "geographically separate sites," which are then capable of simultaneously entering consciousness. Time-locked enhancement is thus a candidate for a single consciousness-making process. This putative process occurs simultaneously at many separate sites, and is unitary in virtue of being phase-locked, or falling within a single well defined temporal window of some kind.

2.2 Single-track versus multi-track models of consciousness

It is reasonable to ask whether such approaches to consciousness are the only option. Once it is acknowledged that instantaneous consciousness is polyphonic, and once this fact is considered in the light of the parcellation of information processing in the brain, an alternative way of thinking about the relationship between the structure of consciousness and brain activity clamours for attention. Instead of requiring that the multiple contents of moment by moment experience be re-presented in some central system, or that they be integrated in a single global process, why not suppose that these contents contribute to instantaneous experience via multiple mechanisms of consciousness-making scattered across the brain?

We can‘t resist employing another musical metaphor here to clarify this alternative polyphonic model of consciousness and to distinguish it from its more orthodox counterpart (see O‘Brien & Opie 1998). Before the advent of modern studios the only way to record music was to get all the musicians in a room together, place a microphone in their midst, and start up the band. The signal from the microphone would then go through a limited amount of processing before leaving a groove on a wax disc, or more recently, a magnetic trace on a tape. Such a recording is said to be single-track, since there is no way to separate out the individual contributions of the musicians—they are packaged into a single structure. By contrast, on a multi-track recording one or more separate tracks is devoted to each musical instrument. As a result, while all the musical parts combine to make up the total sound during playback, at the level of the recording one can distinguish between them.

The polyphonic models surveyed thus far are all single-track theories of consciousness. Whether one treats conscious experience as the product of a single, central neural system where informational contents must be re-presented to be made conscious, as in Baars‘ account, or whether one opts for a unitary consciousness-making process that acts simultaneously on the brain‘s many distinct information processing sites, as in Damasio‘s story, one assumes that at the level at which it is made by the brain, instantaneous consciousness is a single thing. When it comes to consciousness-making, the normal brain has just one track. By contrast, a multi-track theory of consciousness regards instantaneous consciousness as being made up of a number of parallel tracks: a collection of phenomenal elements, each generated by a distinct mechanism in the brain.

It might be objected that information in one sensory modality sometimes influences the content of experience in another. A salient example is the McGurk effect, whereby what subjects report hearing is partly determined by what they see. [3] This looks problematic for a multi-track account because the various parts of the polyphonic mix don‘t appear to be truly independent of one another. But the multi-track account is committed only to the claim that the various parts of experience are generated locally, at the very sites where their information contents are fixed. This does not require content-fixations to be completely causally independent of one another. At any given moment there are presumably all sorts of influences, both intra-sensory and inter-sensory, criss-crossing the brain, such that conscious contents not only co-occur, but mutually influence and shape one another. Such causal links are perfectly consistent with the multi-track model, so long as the consciousness-making mechanisms themselves are manifold and localised.

The distinction between single-track and multi-track approaches to consciousness is not well-appreciated in the literature. [4] Because of their unquestioning allegiance to the traditional doctrine of the unity of consciousness, most theorists don‘t even entertain the possibility of a multi-track theory. As a result they overlook what we think is a more parsimonious account of consciousness, one that is more consistent with both our moment by moment phenomenal experience and our neuroscientific understanding of the mechanisms subserving cognition. In the next subsection we examine the evidence, both phenomenological and neuroscientific, in favour of this alternative approach to explaining how the brain makes consciousness.

2.3 Evidence for the multi-track model of consciousness

Consider, first, the phenomenological evidence. Close attention to instantaneous experience reveals it to be a complex aggregate of many elements. Right now, for example, as you concentrate on these sentences, your phenomenal experience is a very rich, comprising: visual experiences (the shapes, textures and colours of these sentences, together with other objects in the room), auditory experiences (noises from outside the room), tactile experiences (the chair pressing against your body), proprioceptive experiences (the position of your limbs), and understanding experiences (what these words and sentences mean), to name a few. These parts are relatively independent, because they can be altered or lost without substantially affecting the others (try closing your eyes for a moment); like the parallel tracks on a multi-track recording, the loss of any one mode of consciousness merely reduces the total "sound."

This independence among the parts of experience is even evident, to some extent, within modalities. Consider the figure below. It can be seen as a flight of stairs in normal orientation, with rear wall uppermost; as an inverted flight of stairs, with front wall uppermost; or even as a flat line drawing, with no perspective. And whichever of these interpretations one adopts, the details of line and colour remain the same. That is, our experience here incorporates not only lines, and regions, but also some abstract phenomenology (a sense of perspective) which is subject to a degree of voluntary control. What is striking here is the looseness of fit between the more abstract and the more concrete parts of experience. It seems that, like a sound engineer, we have some capacity to control which parts go into the mix, and how they will sound.


Figure: Inverting stairs

Although this evidence is suggestive of the multi-track model, it is strictly speaking equivocal where the single-track/multi-track distinction is concerned. The case for multi-track polyphony starts to look quite compelling, however, when these phenomenological data are combined with a range of neuroscientific findings. Neurologists have long studied the experiential consequences of brain injury. They observe complicated patterns of ablation and sparing, both across and within modalities. It is possible, for example, to lose the capacity to visually detect (or experience) motion, while retaining other aspects of visual experience (Zeki 1993, p.82), or to lose colour sensations, while retaining visual form and motion experiences (Sacks 1995, pp.1-38). Phenomenal deficits of this kind are now known to be the result of lesions in specific parts of the brain. Lesion studies have, in fact, been instrumental in establishing the degree and kinds of functional specialisation and localisation in the brain. The picture that is emerging is of a brain which divides and conquers, with broad divisions among modalities and task domains reflected in large-scale anatomical divisions (e.g., primary visual processing in occipital cortex, auditory processing in temporal cortex, planning and working memory in frontal cortex), while more fine-grained functional distinctions are reflected in correspondingly restricted anatomical divisions and loci (e.g, visual motion detection in area V5, colour processing in V4). Other kinds of studies, such as fMRI, PET, micro-electrode and ERP, which are effective over a wide range of spatial and temporal scales, have lately confirmed and enriched this picture with regard to both normal and abnormal function.

The following picture emerges: pathological losses of phenomenology are associated with brain lesions at specific sites, while transient but related alterations in experience (caused by changes in input or task demands) are found to co-vary with activity at these same sites. Thus, variations in conscious experience appear to march in lock-step with reproducible, physically localised variations in brain activity, variations, moreover, at brain sites where the relevant informational contents are thought to be encoded. From here it is a short step to the following conclusion: the brain sites that code for particular informational contents are the very sites where those contents are made conscious. Since the contents and associated brain loci are multiple, phenomenal consciousness is multi-track.

A further, tantalising, piece of evidence for the multi-track model has recently been discovered by Zeki and Bartels. They discuss experimental work on visual processing that suggests that when the different attributes of a visual scene are presented simultaneously, these attributes are not perceived at the same time. It appears that colour is perceived before orientation, which in turn is perceived before motion, the difference between colour and motion being about 60-80 ms (Bartels & Zeki 1998, p.2329). Experiments in which subjects are asked to pair two rapidly alternating states of two attributes (e.g., a bar with two possible orientations and two possible colours), reveal systematic misbinding of attributes relative to their actual time of occurrence (Zeki & Bartels 1998, p.1583). This suggests to Zeki and Bartels that there are "multiple visual micro-consciousnesses which are asynchronous with respect to each other" (p.1584), which in turns leads them to advocate a multi-track theory: "consciousness is not a unitary faculty, but…consists of many micro-consciousnesses" (Bartels & Zeki 1998, p.2327).

The upshot of all this is that the multi-track model of phenomenal consciousness has to be taken quite seriously. It is consistent with the phenomenological and neuroscientific evidence, and doesn‘t succumb to any obvious a priori objections. Rather, this model appears a viable alternative to current single-track orthodoxy.



3. The Emergence of the Self


One area where abandoning the traditional doctrine of the unity of consciousness has major ramifications is in our understanding of the self. Single-track theorists typically explain how the brain constructs a self by deploying exactly the same resources they use to explain the generation of conscious experience. From this perspective, the self and its experiences represent a package deal: the very existence of the latter presupposes the existence of the former. [5] This is part of the "conventional wisdom" to which we alluded in the introduction. But it is wisdom that is put under pressure by the symptoms of schizophrenia. Schizophrenia, in its delusional variant, is a condition that impairs some aspects of self-consciousness while leaving others intact. In particular, sense of agency can come apart from sense of subjectivity. This suggests that the self, when all is well, is a complex entity constructed out of independently conscious parts: a multiplicity, not a unity.

In this section we briefly discuss these implications of the multi-track model of consciousness for the nature of the self, and examine some recent speculations about the neurological basis of schizophrenia which support this perspective.

According to the multi-track model, conscious experience is not unitary; it is a complex amalgam of co-conscious elements, each generated by a distinct consciousness-making mechanism somewhere in the brain. If one adopts this perspective then it is no longer possible to regard self-consciousness as the product of a centralised workspace, or of a single global process such as time-locked co-activation. Consciousness ceases to be a package deal as far as its neural realisation is concerned — there are as many independent physical loci of consciousness as there are distinct information processing paths in the brain. This means, of course, that our conjectures about the degree of parcellation of self-directed experience are answerable to the neurocomputational facts. But the symptoms of schizophrenia already offer some grounds for expecting there not to be a single neural locus of self and self-consciousness. At a first pass, then, we ought to be wary of the view that the conscious self is physically unitary in the strong sense implied by the doctrine of the unity of consciousness.

As it happens, current conjectures about the neural basis of schizophrenia provide a good deal of support for this multi-track perspective on the self. It is widely held that the positive symptoms of schizophrenia are a pathology of agency, involving changes in the consciousness of action (Frith et al 1998, Georgieff & Jeannerod 1999). The leading hypothesis about the physical basis of the disease is that it results from a breakdown in communication among a number of brain regions, including frontal, temporal and cingulate cortices, and various subcortical structures. This lack of integration is thought to be a kind of temporal disconnection syndrome caused by the desynchronisation of numerous widely distributed neural systems (Cleghorn & Albert 1990, Vogeley 1999). Hand in hand with this hypothesis goes a view about the neural basis of self, namely, that it depends on many distinct centres of self-representation within the brain; from cortical regions associated with somatotopic body mapping and action mapping, through regions that function to distinguish between self-initiated and externally caused events (Georgieff & Jeannerod 1998), up to regions such as prefrontal cortex that play a crucial role in organising behaviour. Georgieff and Jeannerod conclude that:
…functions like agency or self-consciousness cannot be mapped on a single localization, even if the involved area seems to fulfill criteria for such a function, in terms of multimodal coding, spatial and temporal integration, etc. The solution to this problem would be to continue further in the direction of fractionating such broad entities as self-construct into more operational elements, and then to relate these elements to specific cortical functions. (1999, Sect. 2.2)
On a view like this, self-consciousness clearly comes out as multi-track, and the changes in sense of agency associated with schizophrenia as failures of integration among distinct self-representing regions, probably caused by their temporal disconnection.

But if phenomenal consciousness, and self-consciousness, in particular, are multi-track, what is one to make of the impression most of us have of being a single, integrated subject? Or, to put it more tendentiously: How does a self emerge from the multiplicity of consciousness? This is a difficult question, largely because there are several senses in which one might claim to be a "single subject." Without entering into that murky territory here, we can offer one relatively straightforward answer that is consistent with the multi-track model of consciousness: a self emerges when the multiple tracks of self-directed experience produced by the brain are sufficiently representationally coherent. [6] Representational coherence concerns the way the various contents of experience relate to each other. In normal circumstances we don‘t experience a ―blooming, buzzing confusion‖, but a structured world of discrete objects arrayed in space, a world in which events unfold in a regular, law-like way, and in which informational contents fall into meaningful spatiotemporal patterns. This registration of contents, which is both intra-modal (e.g., colour and form) and inter-modal (e.g., the registration of proprioceptive, auditory and visual contents as one types on a keyboard), also occurs at the level of specifically self-directed representations. Thus, I typically recognise an action as mine as I perform it, am aware of how it fits with my plans, and discover how it affect things about me (and vice versa), all in a real-time, rapidly up-dated feedback cycle.

Representational coherence is not an invariable feature of conscious experience—it is a hard-won computational achievement, as demonstrated by the many cases (often the result of trauma) in which the brain fails to produce an integrated model of the world. [7] The emergence of a self therefore presumably depends on some mechanism that acts to bring the multiple, locally generated contents of conscious experience into register with one another. In particular, such a mechanism must render coherent the multiple streams of self-representation upon which so much of our behaviour depends. A promising manoeuvre for the multi-track theorist is to appropriate one of the neural mechanisms/processes that single-track theorists deploy to explain the production of consciousness, and redeploy it in the new role of explaining the brain‘s construction of a self. For example, the multi-track theorist might focus on the ERTAS as a neural structure likely to be involved in global communication and integration, as does Baars, but treat it as a self-maker, rather than a consciousness-maker.

If we adopt this proposal then it is possible to regard instantaneous consciousness as a multiplicity, rather than a unity, and yet still claim that it is "unified." The sense in which consciousness is "unified" is not a matter of oneness, but a matter of representational coherence. Such coherence, perhaps courtesy of the ERTAS (cortico-cortical circuits may play a role too), goes some way towards explaining how a self emerges from the multiple strands of representational activity in the brain. This proposal is attractive in the current context because it is reasonable to conjecture that schizophrenia is a disease which impairs the capacity of consciousness-making mechanisms to produce a coherent set of experiences. Instead, possibly as a result of desynchronisation, these mechanisms operate in an autonomous fashion, producing experiences whose contents are disconnected and discontinuous with one another. This gives rise to the familiar symptoms of schizophrenia. In the case of delusions of thought insertion, for example, it is precisely because one part of the brain generates a thought that is representationally discontinuous with mental contents being produced elsewhere that the patient judges it to be alien, and hence disowns it. What we see here is a partial disintegration of the self, but not in the sense of the self failing to be a single thing—on the multi-track view it was never that in the first place—rather, in the sense that the many self-directed representations produced by the brain no longer hang together as a coherent system.

We finish with a word of caution. Although representational coherence may play a pivotal role in the emergence of our sense of agency, it is not clear that it can account for what we earlier termed our "sense of subjectivity." Schizophrenics and others who suffer quite radical breakdowns in the connectedness and continuity of their experience generally have no doubt that these anomalous experiences belong to them (see above). The representational incoherence of the parts of experience doesn‘t appear to undermine the phenomenal "togetherness" that characterises a single subject of experience. A multi-track theorist must therefore appeal to a different set of resources to account for this feature of consciousness. One possibility is that such subject unity depends on some feature of brain organization more basic than that which is responsible for representational coherence. For example, the very causal connectedness of the brain as a whole, which is such that a signal can pass from any part of the brain to any other via no more than half a dozen synapses, might be the physical basis of subject unity—even under conditions where representational coherence has broken down. The detailed working out of this proposal is, however, a task we must leave for another time.

Notes

1. There is evidence, however, that many of the delusions classified as verbal hallucinations are much closer in their phenomenology to thought insertion. See Graham & Stephens 1994, pp.94-97.
2. The distinction between subjectivity and agency is nicely developed in Graham & Stephens 1994.
3. See McGurk & MacDonald 1976. We owe this example to Tim Bayne. For Bayne‘s critique of the multi-track model, and our reply, see Bayne 2000 and O‘Brien & Opie 2000, respectively.
4. The only other place we have seen this distinction explicitly drawn is in a recent discussion of consciousness by Searle (2000). Searle distinguishes between what he calls the unified field approach (single-track model) and the building block approach (multi-track model). Having said that, Damasio shows himself to be alive to the possibility of a multi-track theory (see his 1999, esp.pp.123-4 and pp.165-6)
5. See, for example, Damasio 1999.
6. We use the word ‗sufficiently‘ in this characterisation advisedly, since it renders selfhood a matter of degree. We regard this as a strength of the proposal.
7. To take a single example, subjects recovering from damage to striate cortex sometimes have quite peculiar visual phenomenology as the visual elements that are normally bound individually "reappear":
At first the patient will see pure motion (usually rotary) without any form or colour. Then brightness perception returns as a pure Ganzfield – a uniform brightness covering the whole visual field. When colours develop they do so in the form of ‗space‘ or ‗film‘ colours not attached to objects. The latter develop as fragments which join together and eventually the colours enter their objects to complete the construction of the phenomenal object. (Smythies 1994, p.313)
Normal integration of colour and form to produce coherent objects is initially absent here. Schizophrenia likewise results from an inability to integrate distinct informational contents, but at the level of self-consciousness, such that self-initiated actions or thoughts fail to be recognised as one‘s own.


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