Involuntary symbol manipulation (Pig Latin) from external control: Implications for thought suppression

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.

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.

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.

The Generation of Involuntary Mental Imagery in an Ecologically-Valid Task

Laboratory tasks (e.g., the flanker task) reveal that incidental stimuli (e.g., distractors) can reliably trigger involuntary conscious imagery. Can such involuntary effects, involving competing representations, arise during dual-task conditions? Another concern about these laboratory tasks is whether such effects arise in highly ecologically-valid conditions. For example, do these effects arise from tasks involving dynamic stimuli (e.g., simulations of semi-automated driving experiences)? The data from our experiment suggest that the answer to our two questions is yes. Subjects were presented with video footage of the kinds of events that one would observe if one were seated in the driver's seat of a semi-automated vehicle. Before being presented with this video footage, subjects had been trained to respond to street signs according to laboratory techniques that cause stimulus-elicited involuntary imagery. After training, in the Respond condition, subjects responded to the signs; in the Suppress condition, subjects were instructed to not respond to the signs in the video footage. Subjects in the Suppress condition reported involuntary imagery on a substantive proportion of the trials. Such involuntary effects arose even under dual-task conditions (while performing the n-back task or psychomotor vigilance task). The present laboratory task has implications for semi-automated driving, because the safe interaction between driver and vehicle requires that the communicative signals from vehicle to driver be effective at activating the appropriate cognitions and behavioral inclinations. In addition, our data from the dual-task conditions provide constraints for theoretical models of cognitive resources.

EEG Correlates of Involuntary Cognitions in the Reflexive Imagery Task

The Reflexive Imagery Task (RIT) reveals that the activation of sets can result in involuntary cognitions that are triggered by external stimuli. In the basic RIT, subjects are presented with an image of an object (e.g., CAT) and instructed to not think of the name of the object. Involuntary subvocalizations of the name (the RIT effect) arise on roughly 80% of the trials. We conducted an electroencephalography (EEG) study to explore the neural correlates of the RIT effect. Subjects were presented with one object at a time in one condition and two objects simultaneously in another condition. Five regions were defined by electrode sites: frontal (F3-F4), parietal (P3-P4), temporal (T3-T4), right hemisphere (F4-P4), and left hemisphere (F3-P3). We focused on the alpha (8-13 Hz), beta (13-30 Hz), delta (0.01-4 Hz), and theta (4-8 Hz) frequencies.

Involuntary attentional shifts as a function of set and processing fluency

In laboratory tasks, involuntary cognitions of various kinds (e.g., mental imagery) have been elicited by external stimuli. These effects reveal, among other things, the capacities of involuntary processes. In most cases, these cognitions do not require, for their generation, executive functions such as a shift in selective attention. In Experiment 1, subjects were presented with a clock of 12 words in the stead of numbers and were instructed to focus on the center of the screen and to not count the number of letters of a word at a certain location. Involuntary counting of the critical word occurred on 39% of the trials. This effect requires an involuntary shift of attention. Experiment 2, involving Chinese ideographs, concerned the effect of stimulus fidelity and processing fluency. Native English speakers and a separate group of subjects who could read Chinese ideographs were presented with an array similar to that of Experiment 1 and instructed to not read any of the words. Some words were easy to read (e.g., regular Chinese words and English words), and some words were more difficult to read (e.g., Chinese "loan" words and English pseudowords). For the subjects who could read Chinese ideographs, more involuntary reading occurred for regular ideographs than for loan words. For the Native English speakers, comparable effects were found with the English stimuli. Together, these studies reveal that attentional phenomena of this kind can be influenced involuntarily and systematically through external control.

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 Entry Into Consciousness From the Activation of Sets: Object Counting and Color Naming

High-level cognitions can enter consciousness through the activation of certain action sets and the presentation of external stimuli (“set-based entry,” for short). Set-based entry arises in a manner that is involuntary and systematic. In the Reflexive Imagery Task, for example, subjects are presented with visual objects and instructed to not think of the names of the objects. Involuntary subvocalizations arise on roughly 80% of the trials. We examined whether or not set-based entry can also occur in the case of involuntary counting. Subjects in Experiment 1A were instructed to not count the number of objects presented in an array. Involuntary counting arose on a high proportion of the trials (a mean proportion of ∼0.90) for stimulus arrays having 2–5 objects, and such counting arose less frequently across trials when the array consisted of 6–10 objects (a mean proportion of ∼0.21). The data from Experiment 1B revealed that, when people choose to perform Set X, they also experience thoughts about an unselected Set (Set Y). Subjects were trained on one set (e.g., to “color name”) and then, when presented with stimuli, were given the choice to perform the trained set or a novel set. Consistent with theories proposing that the conscious contents represent several potential action plans, subjects were equally likely to experience set-related imagery or set-unrelated imagery. Our findings regarding set-based entry are relevant to many subfields of psychology and neuroscience (e.g., the study of high-level mental processes, attention, imagery, and action 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.

The reflexive imagery task: An experimental paradigm for neuroimaging

High-level cognitions can be triggered into consciousness through the presentation of external stimuli and the activation of certain action sets. These activations arise in a manner that is involuntary, systematic and nontrivial. For example, in the Reflexive Imagery Task (RIT), subjects are presented with visual objects and instructed to not think of the names of the objects. Involuntary subvocalizations arise on roughly 80% of the trials. We review the findings from this paradigm, discuss neural findings that are relevant to the RIT, and present new data that further corroborate the reliability and robustness of the RIT, a paradigm that could be coupled with neuroimaging technologies. We developed an RIT variant in which two, non-focal objects are presented simultaneously. In previous RITs, visual objects were presented only one at a time, in the center of the screen, and subjects were instructed to focus on the center of the screen, where these objects were presented. Replicating the RIT effect, involuntary subvocalizations still occurred on a high proportion of trials (M = 0.78). An RIT effect arose for both objects on a considerable proportion of the trials (M = 0.35). These findings were replicated in a second experiment having a different sample of subjects. Our findings are relevant to many subfields of neuroscience (e.g., the study of high-level mental processes, attention, imagery and action control).

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.

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.