Encapsulation and subjectivity from the standpoint of viewpoint theory.

The groundbreaking, viewpoint theory of Merker et al. explains several properties of the conscious field, including why the observer cannot directly apprehend itself. We propose that viewpoint theory might also provide a progressive, constitutive marker of consciousness and shed light on why most of the contents of consciousness are encapsulated.

Involuntary mental rotation and visuospatial imagery from external control.

The Reflexive Imagery Task (RIT) was developed to investigate the entry into consciousness of involuntary imagery. Subjects are presented with objects and instructed to not think of the names of the objects. Involuntary subvocalizations arise on many trials. RIT effects reveal the capacities of involuntary processing. These cognitions do not require symbol manipulation. Can mental rotation and visuospatial imagery, too, arise in this involuntary manner? In the mental rotation task, subjects were first taught to mentally rotate two-dimensional objects. Subjects were then instructed to not mentally rotate objects. In the chess task, subjects were taught how to move in their minds objects in specified ways, much as one could imagine how chess pieces move on a chessboard. Subjects were then instructed to not have such visuospatial imagery. For both tasks, involuntary imagery occurred on a substantial proportion of trials, revealing that symbol manipulation can be influenced involuntarily through external control.

Involuntary polymodal imagery involving olfaction, audition, touch, taste, and vision.

Percepts and urges often enter consciousness involuntarily. The Reflexive Imagery Task (RIT) reveals how high-level cognitions, too, can enter consciousness involuntarily. In the task, the eliciting stimuli are visual (e.g., picture of a cat), and the involuntary imagery is verbal (e.g., the subvocalization "cat"). The generalizability of the RIT effect has been questioned because verbal imagery is an easily elicited form of imagery. Do such effects arise for other kinds of imagery? It is known that imagery is more elicitable in some senses (e.g., vision) than in other senses (e.g., olfaction). We found such differences in an RIT in which food items were presented as orthographic stimuli or as drawings. Although subjects were instructed to suppress mental imagery, involuntary imagery still arose: Olfactory (effect in ∼40% of trials), taste (∼54%), touch (∼60%), and visual/auditory (∼79%). Of theoretical import, effects were comparable when the eliciting stimuli were orthographs or visual objects.

Externally controlled involuntary cognitions and their relations with other representations in consciousness.

Percepts and action-related urges often enter consciousness insuppressibly. The Reflexive Imagery Task (RIT) was developed to investigate how high-level cognitions (e.g., subvocalizations), too, can enter consciousness in this manner. Limitations of the paradigm include (a) that no data have confirmed subjects' introspections about the involuntary subvocalizations, and (b) that, in everyday life, adaptive responses to involuntary cognitions often depend on the nature of the other contents in consciousness. To address a and b, we developed an RIT in which subjects were presented with visual objects and instructed to not think of the object names. If a subvocalization did arise, however, subjects responded motorically only if the subvocalization rhymed with a word held in memory and if there was a visual "go" cue. Subjects successfully (on 0.83 of the trials) emitted this complex, "multi-determined" response, which provides evidence for the occurrence of the involuntary subvocalizations and illuminates the function of consciousness.

Conscious contents as reflexive processes: Evidence from the habituation of high-level cognitions.

Reflexes are often insuppressible, predictable, and susceptible to external control. In contrast, conscious thoughts have been regarded as whimsical, 'offline,' and shielded from external control. Recent advances suggest that conscious thoughts are more reflex-like and susceptible to external control than previously thought. In one paradigm, high-level conscious thoughts (subvocalizations) are triggered by external control, as a function of external stimuli and experimenter-induced action sets. It has been hypothesized that these conscious contents are activated involuntarily and in a reflex-like manner. If such is the case, then these activations should possess a well-known property of the reflex: habituation. Accordingly, we found that involuntary high-level cognitions (subvocalizations) habituated (i.e., were less likely to arise) after repeated stimulation. As in the case of the habituation of a reflex, this novel effect was stimulus-specific. We discuss the implications of this finding for theories about consciousness and about psychopathological phenomena involving undesired, involuntary cognitions.

Homing in on consciousness in the nervous system: An action-based synthesis.

What is the primary function of consciousness in the nervous system? The answer to this question remains enigmatic, not so much because of a lack of relevant data, but because of the lack of a conceptual framework with which to interpret the data. To this end, we have developed Passive Frame Theory, an internally coherent framework that, from an action-based perspective, synthesizes empirically supported hypotheses from diverse fields of investigation. The theory proposes that the primary function of consciousness is well-circumscribed, serving the somatic nervous system. For this system, consciousness serves as a frame that constrains and directs skeletal muscle output, thereby yielding adaptive behavior. The mechanism by which consciousness achieves this is more counterintuitive, passive, and "low level" than the kinds of functions that theorists have previously attributed to consciousness. Passive frame theory begins to illuminate (a) what consciousness contributes to nervous function, (b) how consciousness achieves this function, and (c) the neuroanatomical substrates of conscious processes. Our untraditional, action-based perspective focuses on olfaction instead of on vision and is descriptive (describing the products of nature as they evolved to be) rather than normative (construing processes in terms of how they should function). Passive frame theory begins to isolate the neuroanatomical, cognitive-mechanistic, and representational (e.g., conscious contents) processes associated with consciousness.

Passive frame theory: A new synthesis.

Passive frame theory attempts to illuminate what consciousness is, in mechanistic and functional terms; it does not address the "implementation" level of analysis (how neurons instantiate conscious states), an enigma for various disciplines. However, in response to the commentaries, we discuss how our framework provides clues regarding this enigma. In the framework, consciousness is passive albeit essential. Without consciousness, there would not be adaptive skeletomotor action.

External control of the stream of consciousness: Stimulus-based effects on involuntary thought sequences.

The stream of consciousness often appears whimsical and free from external control. Recent advances, however, reveal that the stream is more susceptible to external influence than previously assumed. Thoughts can be triggered by external stimuli in a manner that is involuntary, systematic, and nontrivial. Based on these advances, our experimental manipulation systematically triggered a sequence of, not one, but two involuntary thoughts. Participants were instructed to (a) not subvocalize the name of visual objects and (b) not count the number of letters comprising object names. On a substantial proportion of trials, participants experienced both kinds of involuntary thoughts. Each thought arose from distinct, high-level processes (naming versus counting). This is the first demonstration of the induction of two involuntary thoughts into the stream of consciousness. Stimulus word length influenced dependent measures systematically. Our findings are relevant to many fields associated with the study of consciousness, including attention, imagery, and action control.

Subjective aspects of working memory performance: memoranda-related imagery.

Although it is well accepted that working memory (WM) is intimately related to consciousness, little research has illuminated the liaison between the two phenomena. To investigate this under-explored nexus, we used an imagery monitoring task to investigate the subjective aspects of WM performance. Specifically, in two experiments, we examined the effects on consciousness of (a) holding in mind information having a low versus high memory load, and (b) holding memoranda in mind during the presentation of distractors (e.g., visual stimuli associated with a response incompatible with that of the memoranda). Higher rates of rehearsal (conscious imagery) occurred in the high load and distractor conditions than in comparable control conditions. Examination of the temporal properties of the rehearsal-based imagery revealed that, across subjects, imagery events occurred evenly throughout the delay. We hope that future variants of this new imagery monitoring task will reveal additional insights about WM, consciousness, and action control.

Stimulus-elicited involuntary autobiographical memories.

The reflexive imagery task (RIT) has been used to investigate stimulus-elicited involuntary mental processes. The task has been successful in eliciting involuntary perceptual experiences, urges, and even higher-order cognitions, but it has never been used to elicit autobiographical memories, even though in everyday life these memories are often activated involuntarily by external stimuli. These memories are different in interesting ways from the kinds of mental representations that have been activated involuntarily in the RIT. The memories have properties which might make them insusceptible to such a form of external influence. Perhaps substantive effects will not arise because the mental representations associated with autobiographical memories are complex, poly-sensory, and rich in terms of content. To investigate this matter, we developed a variant of the RIT in which participants were presented with external stimuli (line drawings of everyday objects) and instructed not to recall any autobiographical memories. We investigated whether the nature of the involuntary memories was influenced by the nature of the stimulus. In two experiments, the involuntary memories were associated to the stimulus on a majority of the trials (∼80%). We discuss theoretical implications of this finding and of identifying the conditions in which such involuntary effects will not arise. The boundary conditions of the RIT effect illuminate the limits of unconscious processing and also the role of conscious processing in nervous function.

Identifying Consciousness in Other Creatures: Three Initial Steps.

Identifying consciousness in other creatures, be they animals or exotic creatures that have yet to be discovered, remains a great scientific challenge. We delineate the first three steps that we think are necessary for identifying consciousness in other creatures. Step 1 is to define the particular kind of consciousness in which one is interested. Step 2 is to identify, in humans, the key differences between the brain processes that are associated with consciousness and the brain processes that are not associated with consciousness. For Step 2, to identify these differences, we focus on passive frame theory. Step 3 concerns how the insights derived from consciousness research on humans (e.g., concerning these differences) can be generalized to other creatures. We discuss the significance of examining how consciousness was fashioned by the process of evolution, a process that could be happenstance and replete with incessant tinkering, yielding adaptations that can be suboptimal and counterintuitive, far different in nature from our efficiently designed robotic systems. We conclude that the more that is understood about the differences between conscious processing and unconscious processing in humans, the easier it will be to identify consciousness in other creatures.

The priming of stimulus-elicited involuntary mental imagery.

Percepts, urges, and even high-level cognitions often enter the conscious field involuntarily. The Reflexive Imagery Task (RIT) was designed to investigate experimentally the nature of such entry into consciousness. In the most basic version of the task, participants are instructed not to subvocalize the names of visual objects. Involuntary subvocalizations arise on the majority of the trials. Can these effects be influenced by priming? In our experiment, participants were exposed to an auditory prime 300 ms before being presented with the RIT stimuli. For example, participants heard the word "FOOD" before seeing two RIT stimuli (e.g., line drawings of BANANA and CAT, with the former being the target of the prime). The short span between prime and target allowed us to assess whether the RIT effect is strategic or automatic. Before each trial, participants were instructed to disregard what they hear, and not to think of the name of any of the objects. On an average of 83% of the trials, the participants thought (involuntarily) of the name of the object associated with the prime. This is the first study to use a priming technique within the context of the RIT. The theoretical implications of these involuntary effects are discussed.

Neural correlates of the essence of conscious conflict: fMRI of sustaining incompatible intentions.

The study of intrapsychic conflict has long been central to many key theories about the control of behavior. More recently, by focusing on the nature of conflicting processes in the brain, investigators have revealed great insights about controlled versus automatic processes and the nature of self-control. Despite these advances, many theories of cognitive control or self-control remain agnostic about the function of subjective awareness (i.e., basic consciousness). Why people consciously experience some conflicts in the nervous system but not others remains a mystery. One hypothesis is that people become conscious only of conflicts involving competition for the control of skeletal muscle. To test one aspect of this larger hypothesis, in the present study, 14 participants were trained to introspect the feeling of conflict (the urge to make an error during a Stroop color-word interference task) and then were asked to introspect in the same way while sustaining simple compatible and incompatible intentions during fMRI scanning (to move a finger left or right). As predicted, merely sustaining incompatible skeletomotor intentions prior to their execution produced stronger systematic changes in subjective experience than sustaining compatible intentions, as indicated by self-report ratings obtained in the scanner. Similar ratings held for a modified Stroop-like task when contrasting incompatible versus compatible trials also during fMRI scanning. We use subjective ratings as the basis of parametric analyses of fMRI data, focusing a priori on the brain regions involved in action-related urges (e.g., parietal cortex) and cognitive control (e.g., dorsal anterior cingulate cortex, lateral PFC). The results showed that subjective conflict from sustaining incompatible intentions was consistently related to activity in the left post-central gyrus.

Conscious thoughts from reflex-like processes: a new experimental paradigm for consciousness research.

The contents of our conscious mind can seem unpredictable, whimsical, and free from external control. When instructed to attend to a stimulus in a work setting, for example, one might find oneself thinking about household chores. Conscious content thus appears different in nature from reflex action. Under the appropriate conditions, reflexes occur predictably, reliably, and via external control. Despite these intuitions, theorists have proposed that, under certain conditions, conscious content resembles reflexes and arises reliably via external control. We introduce the Reflexive Imagery Task, a paradigm in which, as a function of external control, conscious content is triggered reliably and unintentionally: When instructed to not subvocalize the name of a stimulus object, participants reliably failed to suppress the set-related imagery. This stimulus-elicited content is considered 'high-level' content and, in terms of stages of processing, occurs late in the processing stream. We discuss the implications of this paradigm for consciousness research.

The habituation of higher-order conscious processes: Evidence from mental arithmetic.

A recurring idea in psychology is that one is conscious only of the "outputs" of mental operations, but not of the operations themselves. Often, such "entry into consciousness" occurs involuntarily. To investigate involuntary entry, some experimentalists have used the reflexive imagery task (RIT). The RIT has revealed that, under certain conditions, external stimuli (e.g., line drawings) can elicit involuntary entry of high-level cognitions. In the basic version of the task, participants are presented with visual objects and instructed not to subvocalize (i.e., say in one's head) the names of these objects. Participants cannot suppress these subvocalizations on a majority of the trials. It has been proposed that, if RIT effects resemble a reflex, then perhaps they will habituate as reflexes do. In the "habituation" variant of the RIT, the same stimulus object (e.g., CAT) is presented on ten consecutive trials (ten "instantiations"), in order to induce habituation (i.e., a weakened RIT effect). It remains unknown whether such habituation effects arise for stimulus-elicited processes that depend, not on subvocalization, but on more complex processes, such as mental arithmetic. To illuminate this issue, we conducted a conceptual replication of the "habituation" RIT that involves, on each trial, the participant trying not to add two numbers (e.g., 14 and 2). We assessed whether the habituation effects were stimulus-specific or set-specific. Understanding the boundary conditions of the RIT effect and its habituation illuminates the limits of unconscious processes and the role of conscious processing.

Involuntary refreshing of mental representations.

Laboratory tasks have revealed that mental representations (e.g., mental imagery) can enter consciousness in a manner that is involuntary, reliable, and insuppressible. These effects illuminate the capacities of involuntary processes as well as the function of voluntary, conscious processing. The Reflexive Imagery Task was developed a decade ago to investigate these involuntary effects systematically. Can refreshing yield such involuntary effects? Refreshing is the reactivating in mind of a mental representation that was activated moments ago. It is associated with mental rehearsal and executive function. We investigated whether a mental representation (subvocalization of an object name) can arise in consciousness involuntarily after a delayed interval, when the relevant stimulus is no longer present, and in response to a cue. In Experiment 1, participants were instructed not to refresh a previously presented (6 s before) stimulus in response to a cue. Involuntary refreshing occurred on a substantive proportion (0.56) of the trials. Experiment 2 replicated and extended this finding (proportion of the trials = 0.53) with a refreshing task that was more challenging than that of Experiment 1. Our findings suggest that mental representations arising from processes such as refreshing can occur involuntarily. We discuss the theoretical implications of this conclusion.

Stimulus-Elicited Involuntary Cognition: Boundary Conditions and Systematic Effects.

For decades, researchers have been presenting participants with stimuli and instructing the participants not to respond to the stimuli in some way. Today, researchers are studying the effects that such stimuli have, not only on behavior, but on conscious experience. To this end, researchers have used several laboratory tasks, including the reflexive imagery task (RIT). In the RIT, participants are instructed not to respond in a specific way to stimuli. Participants often cannot suppress such responses. Knowledge of the conditions under which RIT effects fail to arise can illuminate the limitations of involuntary processes. We observed that the RIT effect can survive with brand symbols (Experiment 1, n = 30), which are different from everyday objects in interesting ways. In addition, we investigated systematic effects. Systematic effects are unlikely to be due to experimental demand. In Experiment 2 (n = 48), we observed that RIT effects could arise from associations learned, not across the participant's lifetime, but only in the laboratory. Participants studied nonsense shapes that were associated with pseudowords that preceded or followed the shapes. Afterward, these new associations led to RIT effects. In addition, RIT effects were more likely for pseudowords that preceded the shapes rather than for the pseudowords that followed the shapes (a systematic effect). In Experiment 3 (n = 46), systematic effects involving two sensory modalities were observed: olfactory stimuli were more likely to elicit involuntary visual imagery than visual stimuli were to elicit involuntary olfactory imagery. We discuss the theoretical implications of these effects.

Insuppressible cognitions in the reflexive imagery task: Insights and future directions.

In 1959, Neal Miller made the bold claim that the Stimulus-Response, Behaviorist models of that era were describing the way in which stimuli lead to the entry of contents into consciousness ("entry," for short). Today, researchers have begun to investigate the link between external stimuli and involuntary entry, using paradigms such as the reflexive imagery task (RIT), the focus of our review. The RIT has revealed that stimuli can elicit insuppressible entry of high-level cognitions. Knowledge of the boundary conditions of the RIT effect illuminates the limitations of involuntary processes and the role of consciousness in the regulation of behavior. We review the boundary conditions of this paradigm as well as its systematic effects. Systematic effects are unlikely to be due to experimental demand. While reviewing each effect, we consider its theoretical implications. In addition, throughout our review, we discuss future directions for the study of insuppressible entry using the RIT. Last, we discuss a theoretical development (passive frame theory) that stems from the RIT and illuminates how involuntary entry and encapsulation, though at times disadvantageous for the actor, are essential for adaptive action selection during the course of ontogeny.

Cognitive and neural components of the phenomenology of agency.

A primary aspect of the self is the sense of agency ­ the sense that one is causing an action. In the spirit of recent reductionistic approaches to other complex, multifaceted phenomena (e.g., working memory; cf. Johnson &Johnson, 2009), we attempt to unravel the sense of agency by investigating its most basic components, without invoking high-level conceptual or 'central executive' processes. After considering the high-level components of agency, we examine the cognitive and neural underpinnings of its low-level components, which include basic consciousness and subjective urges (e.g., the urge to breathe when holding one's breath). Regarding urges, a quantitative review revealed that certain inter-representational dynamics (conflicts between action plans, as when holding one's breath) reliably engender fundamental aspects both of the phenomenology of agency and of 'something countering the will of the self'. The neural correlates of such dynamics, for both primordial urges (e.g., air hunger) and urges elicited in laboratory interference tasks, are entertained. In addition, we discuss the implications of this unique perspective for the study of disorders involving agency.