Toward a phenomenology of inner speaking

Not Everybody Has an Inner Voice: Behavioral Consequences of Anendophasia

It is commonly assumed that inner speech-the experience of thought as occurring in a natural language-is a human universal. Recent evidence, however, suggests that the experience of inner speech in adults varies from near constant to nonexistent. We propose a name for a lack of the experience of inner speech-anendophasia-and report four studies examining some of its behavioral consequences. We found that adults who reported low levels of inner speech (N = 46) had lower performance on a verbal working memory task and more difficulty performing rhyme judgments compared with adults who reported high levels of inner speech (N = 47). Task-switching performance-previously linked to endogenous verbal cueing-and categorical effects on perceptual judgments were unrelated to differences in inner speech.

The effects of internal representations on performance and fluidity in a motor task

Individuals can differ in the mode in which they experience conscious thought. These differences in visualisation and verbalisation can also be evident during motor control. The Internal Representation Questionnaire (IRQ) was developed to measure propensity to engage certain types of representations, but its ability to predict motor control and links to reinvestment and motor imagery have not been tested. 159 included participants completed the IRQ, movement specific reinvestment scale (MSRS), and a novel online motor task before and after a period of practice. Results showed that the IRQ Verbal and Orthographic factors were significant predictors of scores on the MSRS. The IRQ factor of Manipulational Representations predicted motor performance both before and after practice. The fluidity of executed movements were predicted by the IRQ verbalisation factor where higher propensity to verbalise was associated with higher levels of jitter, but only after a period of practice. Results suggest there may be some informative conceptual overlap between internal verbalisations and reinvestment and that the propensity to manipulate internal representations may be predictive of motor performance in new tasks. The IRQ has potential to be a valuable tool for predicting motor performance.

Inner speech and the body error theory

Inner speech is commonly understood as the conscious experience of a voice within the mind. One recurrent theme in the scientific literature is that the phenomenon involves a representation of overt speech, for example, a representation of phonetic properties that result from a copy of speech instructions that were ultimately suppressed. I propose a larger picture that involves some embodied objects and their misperception. I call it "the Body Error Theory," or BET for short. BET is a form of illusionism, but the particular version I favor is a cross-modal illusion. Newly described here, my hypothesis is that the experience of inner speech arises from a mix of interoception and audition. Specifically, there is the detection of slight but well-confirmed activities in the speech musculature that occur during inner speech, which helps to transform representations of normal but quiet nonverbal sounds that inevitably occur during inner speech, from breathing to background noise, into a mistaken perception of inner speech. Simply put, activities in the speech musculature mix with sounds to create the appearance of speech sounds, which thus explains the "voice within the mind." I also show how BET's cross-modal system fits with standard information processing accounts for speech monitoring and how it accommodates the central insights of leading theories of inner speech. In addition, I show how BET is supported by data from experience-sampling surveys and how it can be empirically tested against its rivals.

Internal speech is faster than external speech: Evidence for feedback-based temporal control

A recent model of temporal control in speech holds that speakers use sensory feedback to control speech rate and articulatory timing. An experiment was conducted to assess whether there is evidence in support of this hypothesis by comparing durations of phrases in external speech (with sensory feedback) and internal speech (without sensory feedback). Phrase lengths were varied by including one to three disyllabic nouns in a target phrase that was always surrounded by overt speech. An inferred duration method was used to estimate the durations of target phrases produced internally. The results showed that internal speech is faster than external speech, supporting the hypothesis. In addition, the results indicate that there is a slow-down associated with transitioning between internal and external modes of production.

Inner speech as language process and cognitive tool

Many people report a form of internal language known as inner speech (IS). This review examines recent growth of research interest in the phenomenon, which has broadly supported a theoretical model in which IS is a functional language process that can confer benefits for cognition in a range of domains. A key insight to have emerged in recent years is that IS is an embodied experience characterized by varied subjective qualities, which can be usefully modeled in artificial systems and whose neural signals have the potential to be decoded through advancing brain-computer interface technologies. Challenges for future research include understanding individual differences in IS and mapping form to function across IS subtypes.

Distinct neural mechanisms support inner speaking and inner hearing

Humans have the ability to mentally examine speech. This covert form of speech production is often accompanied by sensory (e.g., auditory) percepts. However, the cognitive and neural mechanisms that generate these percepts are still debated. According to a prominent proposal, inner speech has at least two distinct phenomenological components: inner speaking and inner hearing. We used transcranial magnetic stimulation to test whether these two phenomenologically distinct processes are supported by distinct neural mechanisms. We hypothesised that inner speaking relies more strongly on an online motor-to-sensory simulation that constructs a multisensory experience, whereas inner hearing relies more strongly on a memory-retrieval process, where the multisensory experience is reconstructed from stored motor-to-sensory associations. Accordingly, we predicted that the speech motor system will be involved more strongly during inner speaking than inner hearing. This would be revealed by modulations of TMS evoked responses at muscle level following stimulation of the lip primary motor cortex. Overall, data collected from 31 participants corroborated this prediction, showing that inner speaking increases the excitability of the primary motor cortex more than inner hearing. Moreover, this effect was more pronounced during the inner production of a syllable that strongly recruits the lips (vs. a syllable that recruits the lips to a lesser extent). These results are compatible with models assuming that the primary motor cortex is involved during inner speech and contribute to clarify the neural implementation of the fundamental ability of silently speaking in one's mind.

Bridging phenomenology and neural mechanisms of inner speech: ALE meta-analysis on egocentricity and spontaneity in a dual-mechanistic framework

The neural mechanisms of inner speech remain unclear despite its importance in a variety of cognitive processes and its implication in aberrant perceptions such as auditory verbal hallucinations. Previous research has proposed a corollary discharge model in which inner speech is a truncated form of overt speech, relying on speech production-related regions (e.g. left inferior frontal gyrus). This model does not fully capture the diverse phenomenology of inner speech and recent research suggesting alternative perception-related mechanisms of generation. Therefore, we present and test a framework in which inner speech can be generated by two separate mechanisms, depending on its phenomenological qualities: a corollary discharge mechanism relying on speech production regions and a perceptual simulation mechanism within speech perceptual regions. The results of the activation likelihood estimation meta-analysis examining inner speech studies support the idea that varieties of inner speech recruit different neural mechanisms.

Private speech improves cognitive performance in young adults

The current study investigated the relationship between private speech usage and cognitive performance in young adults. Participants (n = 103, mean age = 20.21 years) were instructed to complete a visual-spatial working memory task while talking out loud to themselves as much as possible (Private Speech condition). We found that participants performed better on trials for which they produced a greater amount of private speech. To establish causality, we further found that participants performed better in the Private Speech condition than in a condition in which they were instructed to remain silent (Quiet condition). These beneficial effects of private speech were not moderated by task difficulty, which was manipulated by varying image labelability. However, participants who used more private speech during the task, as well as those who reported greater use of self-management private speech in everyday life, showed the greatest benefits. These findings have implications for real-world educational/instructional settings.

A voice without a mouth no more: The neurobiology of language and consciousness

Most research on the neurobiology of language ignores consciousness and vice versa. Here, language, with an emphasis on inner speech, is hypothesised to generate and sustain self-awareness, i.e., higher-order consciousness. Converging evidence supporting this hypothesis is reviewed. To account for these findings, a 'HOLISTIC' model of neurobiology of language, inner speech, and consciousness is proposed. It involves a 'core' set of inner speech production regions that initiate the experience of feeling and hearing words. These take on affective qualities, deriving from activation of associated sensory, motor, and emotional representations, involving a largely unconscious dynamic 'periphery', distributed throughout the whole brain. Responding to those words forms the basis for sustained network activity, involving 'default mode' activation and prefrontal and thalamic/brainstem selection of contextually relevant responses. Evidence for the model is reviewed, supporting neuroimaging meta-analyses conducted, and comparisons with other theories of consciousness made. The HOLISTIC model constitutes a more parsimonious and complete account of the 'neural correlates of consciousness' that has implications for a mechanistic account of mental health and wellbeing.

An Introduction to Engaged Phenomenology

In this article, I introduce engaged phenomenology as an approach through which phenomenologists can more explicitly and critically consider the generative conditions and implications of their research. I make an explicit link between philosophical insights from critical and generative phenomenology and the ethical and methodological insights offered by engaged research methods-a community-oriented approach to the generation of shared understanding for the mutual benefit of all stakeholders in research. The article consists of (a) a review of these respective strands of inquiry, (b) an overview and critique of mainstream qualitative methodologies in phenomenology, and (c) suggestions for those interested in working through engaged phenomenology as an approach to both theory and research praxis.

What Individuals Experience During Visuo-Spatial Working Memory Task Performance: An Exploratory Phenomenological Study

In experimental cognitive psychology, objects of inquiry are typically operationalized with psychological tasks. When interpreting results from such tasks, we focus primarily on behavioral measures such as reaction times and accuracy rather than experiences - i.e., phenomenology - associated with the task, and posit that the tasks elicit the desired cognitive phenomenon. Evaluating whether the tasks indeed elicit the desired phenomenon can be facilitated by understanding the experience during task performance. In this paper we explore the breadth of experiences that are elicited by and accompany task performance using in-depth phenomenological and qualitative methodology to gather subjective reports during the performance of a visuo-spatial change detection task. Thirty-one participants (18 females) were asked to remember either colors, orientations or positions of the presented stimuli and recall them after a short delay. Qualitative reports revealed rich experiential landscapes associated with the task-performance, suggesting a distinction between two broad classes of experience: phenomena at the front of consciousness and background feelings. The former includes cognitive strategies and aspects of metacognition, whereas the latter include more difficult-to-detect aspects of experience that comprise the overall sense of experience (e.g., bodily feelings, emotional atmosphere, mood). We focus primarily on the background feelings, since strategies of task-performance to a large extent map onto previously identified cognitive processes and discuss the methodological implications of our findings.

A complete, unabridged, "pre-registered" descriptive experience sampling investigation: The case of Lena

Descriptive Experience Sampling (DES) attempts to apprehend in high fidelity pristine inner experience (the naturally-occurring, directly-apprehended phenomena that fill our waking lives, including inner speaking, visual imagery, sensory awarenesses, etc.). Previous DES investigations had shown individual differences in the frequency of inner speaking ranging from nearly zero to nearly 100% of the time. In early 2020, the Internet was ablaze with comments expressing astonishment that constant internal monologue was not universal. We invited Lena, a university student who believed she had constant internal monologue, to participate in a DES analog of a pre-registered study: We would announce, on the Internet, that we would conduct a fully transparent DES investigation and roll out videos of the DES interviews (and annotated transcripts) as they occurred in (almost) real-time, something like "reality TV about inner experience," so that spectators could examine for themselves our characterizations of Lena and how we arrived at them. We describe here the procedure and its findings: Lena did not have frequent internal monologue (contrary to her expectations); she did have frequent visual imagery (to her surprise); and we speculated about the frequent presence of two simultaneous "centers of gravity" of her experience. The entire procedure is available for inspection.

Measuring the Frequency of Inner-Experience Characteristics

Inner experience is widely accepted by psychologists and lay people as being straightforwardly observable: Inner speech, visual images, feelings, and so on are understood to be directly apprehendable "before the footlights of consciousness." Many psychologists hold that such characteristics of inner experience play substantial theoretical roles and have applied significance across a wide range of cognitive, affective, performance, and clinical situations. If so, the frequency of occurrence of these characteristics is of fundamental importance. Such frequencies are usually estimated by questionnaires or by questionnaire-based experience sampling. However, there are reasons to wonder about the accuracy of such questionnaire-based estimates. We present three studies that compared, head-to-head, questionnaire-based experiential frequencies with frequencies discovered using descriptive experience sampling (DES), a method for random sampling in the natural environment that aspires to apprehend inner experience with as high fidelity as the state of the art allows. Together, they suggest that estimates of inner-experience frequency produced by questionnaires and DES are irreconcilably discrepant: Questionnaire-based methods produced dramatically higher (from 2 to 4 times as high) frequencies than did DES. These results suggest caution when interpreting questionnaire-based experiential results and the importance of additional high-fidelity studies of inner experience.

Valence, form, and content of self-talk predict sport type and level of performance

In this paper, we aimed to test whether we could predict sport type (badminton or running) and marathon proficiency from the valence, form, and content of the athletes' self-reported inner speech. Additionally, we wanted to assess the difference between self-talk during high intensity and low intensity exercise. The present study corroborated existing research - we were able to predict both sport type in Study 1 and intensity level as well as marathon proficiency in Study 2 from questionnaire data using machine learning models. In Study 1, we found that badminton players engage more in worry and anxiety-control while runners are more prone to task disengagement. Interestingly, it seemed in Study 2 that the more participants engaged in condensed, positive, and repetitive self-talk when not pushing themselves, the slower their fastest marathons and half marathons were. We discuss potential explanations for these findings and make suggestions for future research.

How Abstract (Non-embodied) Linguistic Representations Augment Cognitive Control

Recent scholarship emphasizes the scaffolding role of language for cognition. Language, it is claimed, is a cognition-enhancing niche (Clark, 2006), a programming tool for cognition (Lupyan and Bergen, 2016), even neuroenhancement (Dove, 2019) and augments cognitive functions such as memory, categorization, cognitive control, and meta-cognitive abilities ("thinking about thinking"). Yet, the notion that language enhances or augments cognition, and in particular, cognitive control does not easily fit in with embodied approaches to language processing, or so we will argue. Accounts aiming to explain how language enhances various cognitive functions often employ a notion of abstract representation. Yet, embodied approaches to language processing have it that language processing crucially, according to some accounts even exclusively, involves embodied, modality-specific, i.e., non-abstract representations. In coming to understand a particular phrase or sentence, a prior experience has to be simulated or reenacted. The representation thus activated is embodied (modality-specific) as sensorimotor regions of the brain are thereby recruited. In this paper, we will first discuss the notion of representation, clarify what it takes for a representation to be embodied or abstract, and distinguish between conceptual and (other) linguistic representations. We will then put forward a characterization of cognitive control and examine its representational infrastructure. The remainder of the paper will be devoted to arguing that language augments cognitive control. To that end, we will draw on two lines of research, which investigate how language augments cognitive control: (i) research on the availability of linguistic labels and (ii) research on the active usage of a linguistic code, specifically, in inner speech. Eventually, we will argue that the cognition-enhancing capacity of language can be explained once we assume that it provides us with (a) abstract, non-embodied representations and with (b) abstract, sparse linguistic representations that may serve as easy-to-manipulate placeholders for fully embodied or otherwise more detailed representations.

The Learning-Specific Inner Speech Scale (LISS)

Abstract. Theory and research suggest that inner speech plays a prominent role in students’ learning. To facilitate research on inner speech within learning and academic contexts, we developed a Learning-specific Inner Speech Scale (LISS) used for assessing students spanning a broad range of ages. The LISS takes a functional view of inner speech, assessing the frequency of social-assessing, self-critical, self-reinforcing, and self-managing inner speech in the learning context. Data from three studies based on the child, adolescent, and young adult samples demonstrated that the LISS exhibits acceptable psychometric properties in terms of internal consistency, test-retest reliability, and construct and content validities. In addition, the LISS is age-sensitive and demonstrates a favorably predictive validity for students’ real-life learning performance. The LISS provides researchers and practitioners a useful tool for exploring verbal thinking and its relationships with learning strategies and performance.

The Internal Representations Questionnaire: Measuring modes of thinking

Does the format in which we experience our moment-to-moment thoughts vary from person to person? Many people claim that their thinking takes place in an inner voice and that using language outside of interpersonal communication is a regular experience for them. Other people disagree. We present a novel measure, the Internal Representation Questionnaire (IRQ) designed to assess people's subjective mode of internal representations, and to quantify individual differences in "modes of thinking" along multiple factors in a single questionnaire. Exploratory factor analysis identified four factors: Internal Verbalization, Visual Imagery, Orthographic Imagery, and Representational Manipulation. All four factors were positively correlated with one another, but accounted for unique predictions. We describe the properties of the IRQ and report a test of its ability to predict patterns of interference in a speeded word-picture verification task. Taken together, the results suggest that self-reported differences in how people internally represent their thoughts relates to differences in processing familiar images and written words.

Developing Self-Awareness in Robots via Inner Speech

The experience of inner speech is a common one. Such a dialogue accompanies the introspection of mental life and fulfills essential roles in human behavior, such as self-restructuring, self-regulation, and re-focusing on attentional resources. Although the underpinning of inner speech is mostly investigated in psychological and philosophical fields, the research in robotics generally does not address such a form of self-aware behavior. Existing models of inner speech inspire computational tools to provide a robot with this form of self-awareness. Here, the widespread psychological models of inner speech are reviewed, and a cognitive architecture for a robot implementing such a capability is outlined in a simplified setup.

The role of inner speech on the association between childhood adversity and 'hearing voices'

Adverse childhood experiences are associated with later development of psychosis, particularly auditory verbal hallucinations and delusions. Although auditory hallucinations have been proposed to be misattributed inner speech, the relation between childhood adversity and inner speech has not been previously investigated. The first aim was to test whether childhood adversity is associated with inner speech in persons with psychosis. The second aim was to test for the influence of inner speech on the association between childhood adversity and auditory hallucinations. Our final aim was to test for evidence that would falsify the null hypothesis that inner speech does not impact the relationship between childhood adversity and delusions. In persons with psychosis, we found a positive association between childhood adversity and dialogic inner speech. There was a significant total effect of childhood adversity on auditory hallucinations, including an indirect effect of childhood adversity on auditory hallucinations via dialogic inner speech. There was also a significant total effect of childhood adversity on delusions, but no evidence of any indirect effect via inner speech. These findings suggest that childhood adversities are associated with inner speech and psychosis. The relation between childhood adversity and auditory hallucination severity could be partially influenced by dialogic inner speech.

Neural tracking of speech mental imagery during rhythmic inner counting

The subjective inner experience of mental imagery is among the most ubiquitous human experiences in daily life. Elucidating the neural implementation underpinning the dynamic construction of mental imagery is critical to understanding high-order cognitive function in the human brain. Here, we applied a frequency-tagging method to isolate the top-down process of speech mental imagery from bottom-up sensory-driven activities and concurrently tracked the neural processing time scales corresponding to the two processes in human subjects. Notably, by estimating the source of the magnetoencephalography (MEG) signals, we identified isolated brain networks activated at the imagery-rate frequency. In contrast, more extensive brain regions in the auditory temporal cortex were activated at the stimulus-rate frequency. Furthermore, intracranial stereotactic electroencephalogram (sEEG) evidence confirmed the participation of the inferior frontal gyrus in generating speech mental imagery. Our results indicate that a disassociated neural network underlies the dynamic construction of speech mental imagery independent of auditory perception.

The ConDialInt Model: Condensation, Dialogality, and Intentionality Dimensions of Inner Speech Within a Hierarchical Predictive Control Framework

Inner speech has been shown to vary in form along several dimensions. Along condensation, condensed inner speech forms have been described, that are supposed to be deprived of acoustic, phonological and even syntactic qualities. Expanded forms, on the other extreme, display articulatory and auditory properties. Along dialogality, inner speech can be monologal, when we engage in internal soliloquy, or dialogal, when we recall past conversations or imagine future dialogs involving our own voice as well as that of others addressing us. Along intentionality, it can be intentional (when we deliberately rehearse material in short-term memory) or it can arise unintentionally (during mind wandering). We introduce the ConDialInt model, a neurocognitive predictive control model of inner speech that accounts for its varieties along these three dimensions. ConDialInt spells out the condensation dimension by including inhibitory control at the conceptualization, formulation or articulatory planning stage. It accounts for dialogality, by assuming internal model adaptations and by speculating on neural processes underlying perspective switching. It explains the differences between intentional and spontaneous varieties in terms of monitoring. We present an fMRI study in which we probed varieties of inner speech along dialogality and intentionality, to examine the validity of the neuroanatomical correlates posited in ConDialInt. Condensation was also informally tackled. Our data support the hypothesis that expanded inner speech recruits speech production processes down to articulatory planning, resulting in a predicted signal, the inner voice, with auditory qualities. Along dialogality, covertly using an avatar's voice resulted in the activation of right hemisphere homologs of the regions involved in internal own-voice soliloquy and in reduced cerebellar activation, consistent with internal model adaptation. Switching from first-person to third-person perspective resulted in activations in precuneus and parietal lobules. Along intentionality, compared with intentional inner speech, mind wandering with inner speech episodes was associated with greater bilateral inferior frontal activation and decreased activation in left temporal regions. This is consistent with the reported subjective evanescence and presumably reflects condensation processes. Our results provide neuroanatomical evidence compatible with predictive control and in favor of the assumptions made in the ConDialInt model.

Inner Dialogical Communication and Pathological Personality Traits

Dialogicality and its relation to personality traits have been extensively explored since the evolution of dialogical self theory. However, the latest edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) proposes a new hybrid personality disorder system and, thereby, a new model of pathological personality traits. As of now, there are no studies which show the relationships between self-talk, internal dialogicality, and pathological traits. Thus, the aim of this study was twofold: (a) to investigate the relationship between self-talk and pathological personality traits and (b) to explore the possible affinity between pathological structure of personality and dialogicality. A representative sample of 458 individuals from the non-clinical population, aged 18–67 (M = 30.99, SD = 10.27), including 52% women, completed three questionnaires: the Self-Talk Scale by Brinthaupt et al. (2009), the Internal Dialogical Activity Scale by Oleś (2009), and the Personality Inventory for DSM-5 by Krueger et al. (2012). To verify the correspondence between self-talk, internal dialogues, and pathological personality traits, the Pearson product–moment correlation coefficients (Pearson’s r) and canonical correlation analysis were used. The results supported the hypotheses about the specific relationship between internal dialogical activity and five crucial dysfunctional personality traits related to the hybrid DSM-5 system of diagnosis. People characterized as having emotional lability, anxiousness, and separation insecurity (high negative affectivity), with unusual beliefs and experiences, as well as eccentricity (high psychoticism), are prone to having ruminative and confronting dialogues. The correlation between pathological personality traits and self-talk were statistically significant, but the relationships are very small.

Individual Differences in Self-Talk Frequency: Social Isolation and Cognitive Disruption

Despite the popularity of research on intrapersonal communication across many disciplines, there has been little attention devoted to the factors that might account for individual differences in talking to oneself. In this paper, I explore two possible explanations for why people might differ in the frequency of their self-talk. According to the “social isolation” hypothesis, spending more time alone or having socially isolating experiences will be associated with increased self-talk. According to the “cognitive disruption” hypothesis, having self-related experiences that are cognitively disruptive will be associated with increased self-talk frequency. Several studies using the Self-Talk Scale are pertinent to these hypotheses. The results indicate good support for the social isolation hypothesis and strong support for the cognitive disruption hypothesis. I conclude the paper with a wide range of implications for future research on individual differences in self-talk and other kinds of intrapersonal communication.

A Test Battery for Inner Speech Functions

Objective

Inner speech, or the ability to talk to yourself in your head, is one of the most ubiquitous phenomena of everyday experience. Recent years have seen growing interest in the role and function of inner speech in various typical and cognitively impaired populations. Although people vary in their ability to produce inner speech, there is currently no test battery which can be used to evaluate people's inner speech ability. Here we developed a test battery which can be used to evaluate individual differences in the ability to access the auditory word form internally.

Methods

We developed and standardized five tests: rhyme judgment of pictures and written words, homophone judgment of written words and non-words, and judgment of lexical stress of written words. The tasks were administered to adult healthy native British English speakers (age range 20-72, n = 28-97, varies between tests).

Results

In all tests, some items were excluded based on low success rates among participants, or documented regional variability in accent. Level of education, but not age, correlated with task performance for some of the tasks, and there were no gender difference in performance.

Conclusion

A process of standardization resulted in a battery of tests which can be used to assess natural variability of inner speech abilities among English speaking adults.

Measuring the Frequency of Inner-Experience Characteristics by Self-Report: The Nevada Inner Experience Questionnaire

Descriptive experience sampling has suggested that there are five frequently occurring phenomena of inner experience: inner speaking, inner seeing, unsymbolized thinking, feelings, and sensory awareness. Descriptive experience sampling is a labor- and skill-intensive procedure, so it would be desirable to estimate the frequency of these phenomena by questionnaire. However, appropriate questionnaires either do not exist or have substantial limitations. We therefore created the Nevada Inner Experience Questionnaire (NIEQ), with five subscales estimating the frequency of each of the frequent phenomena, and examine here its psychometric adequacy. Exploratory factor analysis produced four of the expected factors (inner speaking, inner seeing, unsymbolized thinking, feelings) but did not produce a sensory awareness factor. Confirmatory factor analysis validated the five-factor model. The correlation between an existing self-talk questionnaire (Brinthaupt's Self-Talk Scale) and the NIEQ inner speaking subscale provides one piece of concurrent validation.

Neurolinguistics Research Advancing Development of a Direct-Speech Brain-Computer Interface

A direct-speech brain-computer interface (DS-BCI) acquires neural signals corresponding to imagined speech, then processes and decodes these signals to produce a linguistic output in the form of phonemes, words, or sentences. Recent research has shown the potential of neurolinguistics to enhance decoding approaches to imagined speech with the inclusion of semantics and phonology in experimental procedures. As neurolinguistics research findings are beginning to be incorporated within the scope of DS-BCI research, it is our view that a thorough understanding of imagined speech, and its relationship with overt speech, must be considered an integral feature of research in this field. With a focus on imagined speech, we provide a review of the most important neurolinguistics research informing the field of DS-BCI and suggest how this research may be utilized to improve current experimental protocols and decoding techniques. Our review of the literature supports a cross-disciplinary approach to DS-BCI research, in which neurolinguistics concepts and methods are utilized to aid development of a naturalistic mode of communication.

The varieties of inner speech questionnaire - Revised (VISQ-R): Replicating and refining links between inner speech and psychopathology

Inner speech is a common experience for many but hard to measure empirically. The Varieties of Inner Speech Questionnaire (VISQ) has been used to link everyday phenomenology of inner speech - such as inner dialogue - to various psychopathological traits. However, positive and supportive aspects of inner speech have not always been captured. This study presents a revised version of the scale - the VISQ-R - based on factor analyses in two large samples: respondents to a survey on inner speech and reading (N = 1412) and a sample of university students (N = 377). Exploratory factor analysis indicated a five-factor structure including three previous subscales (dialogic, condensed, and other people in inner speech), an evaluative/critical factor, and a new positive/regulatory factor. Confirmatory factor analysis then replicated this structure in sample 2. Hierarchical regression analyses also replicated a number of relations between inner speech, hallucination-proneness, anxiety, depression, self-esteem, and dissociation.

On investigating inner experience: Contrasting Moore & Schwitzgebel and Brouwers et al

Moore and Schwitzgebel (this issue) reported that readers report innerly speak the text about 59% of the time. Brouwers et al. (2018) reported that readers innerly speak the text only about 3% of the time. I use this huge discrepancy as a case study to discuss important issues in the investigation of inner experience, including: the training of participants; ambiguity in the time being considered; ambiguity in the phenomenon; the desirability of investigating the phenomenon itself, not merely its frequency; bracketing presuppositions; the advantages and disadvantages of large and small sample sizes; influence by the investigator; and the slide from phenomena to reports of phenomena.

Pristine Inner Experience and Descriptive Experience Sampling: Implications for Psychology

Pristine inner experience is that which is directly present in awareness before it is distorted by attempts at observation or interpretation. Many psychological methods, including most introspective methods, attempt to measure some aspect of pristine inner experience (thoughts, feelings, mental imagery, sensations, etc.). We believe, however, that these methods produce unspecifiable combinations of pristine inner experience, beliefs about the self, beliefs about what inner experience should be like, inaccurate recollections, miscommunications, and other confounding influences. We argue that descriptive experience sampling (DES) can produce high fidelity descriptions of pristine inner experience. These descriptions are used to create idiographic profiles, carefully crafted, in-depth characterizations of the pristine inner experience of individuals. We believe these profiles, because they are built from moments apprehended via a method that confronts the challenges inherent in examining inner experience, are uniquely valuable in advancing the science of inner experience and psychology broadly. For example, DES observations raise important questions about the veracity of results gathered via questionnaires and other introspective methods, like casual introspection. DES findings also provide high fidelity phenomenological data that can be useful for those developing psychological theories, such as theories of emotional processing. Additionally, DES procedures may allow clinicians and clients to practice valuable skills, like bracketing presuppositions and attending to internal experiences. This paper will describe difficulties inherent in the study of pristine inner experience and discuss implications of high fidelity descriptions of pristine inner experience for psychological research, theory development, and clinical practice.

A Comparison of Computation Span and Reading Span Working Memory Measures' Relations With Problem-Solving Criteria

Researchers have operationalized working memory in different ways and although working memory-performance relationships are well documented, there has been relatively less attention devoted to determining whether seemingly similar measures yield comparable relations with performance outcomes. Our objective is to assess whether two working memory measures deploying the same processes but different item content yield different relations with two problem-solving criteria. Participants completed a computation-based working memory measure and a reading-based measure prior to performing a computerized simulation. Results reveal differential relations with one of the two criteria and support the notion that the two working memory measures tap working memory capacity and other cognitive abilities. One implication for theory development is that researchers should consider incorporating other cognitive abilities in their working memory models and that the selection of those abilities should correspond to the criterion of interest. One practical implication is that researchers and practitioners shouldn't automatically assume that different phonological loop-based working memory scales are interchangeable.

Characteristics of inner reading voices

This study examined the phenomenological characteristics of inner speech during silent reading (inner reading voices or IRVs), a type of inner speech that may be particularly amenable to empirical study. A survey was conducted in the general population to assess IRV frequency, location, number, identity, and controllability, and auditory qualities of IRVs. Of 570 survey respondents, 80.7% reported sometimes or always hearing an inner voice during silent reading, and the remaining 19.3% reported always understanding words being read without hearing an inner voice. Results indicated that IRVs are a routine experience for many, with 34.2% of respondents with IRVs hearing an IRV every time something was read, and 45% reporting an IRV often. Most respondents reported IRVs with specific auditory qualities such as gender, accent, pitch, loudness, and emotional tone. IRVs were reported in participants' own voices, as well as in the voices of other people. Some respondents reported being unable to control any aspect of their IRVs, while others could control one or several aspects. These results indicate that there is considerable individual variation in inner speech during silent reading.

Can Inner Experience Be Apprehended in High Fidelity? Examining Brain Activation and Experience from Multiple Perspectives

We discuss the historical context for explorations of "pristine inner experience," attempts to apprehend and describe the inner experiences that directly present themselves in natural environments. There is no generally accepted method for determining whether such apprehensions/descriptions should be considered high fidelity. By analogy from musical recording, we present and discuss one strategy for establishing experiential fidelity: the examining of brain activation associated with a variety of experiential perspectives that had not been specified at the time of data collection. We beeped participants in an fMRI scanner at randomly-determined times and recorded time-locked brain activations. We used Descriptive Experience Sampling (DES) to apprehend and describe the participant's experience that was ongoing at each beep. These apprehensions/descriptions were obtained with no specific theoretical perspective or experimental intention when originally collected. If these apprehensions/descriptions were of high fidelity, then these pairings of moments of experience and brain activations should be able to be productively examined and re-examined in multiple ways and from multiple theoretical perspectives. We discuss a small set of such re-examinations and conclude that this strategy is worthy of further examination.

[Multidimensionality of inner speech and its relationship with abnormal perceptions]

BACKGROUND

Inner speech is a common human experience. Recently, there have been studies linking this experience with cognitive functions, such as problem solving, reading, writing, autobiographical memory, and some disorders, such as anxiety and depression. In addition, inner speech is recognised as the main source of auditory hallucinations.

OBJECTIVES

The main purpose of this study is to establish the factor structure of Varieties of Inner Speech Questionnaire (VISQ) in a sample of the Colombian population. Furthermore, it aims at establishing a link between VISQ and abnormal perceptions.

METHOD

This was a cross-sectional study in which 232 college students were assessed using the VISQ and the Cardiff Anomalous Perceptions Scale (CAPS).

RESULTS

Through an exploratory factor analysis, a structure of three factors was found: Other Voices in the Internal Speech, Condensed Inner speech, and Dialogical/Evaluative Inner speech, all of them with acceptable levels of reliability. Gender differences were found in the second and third factor, with higher averages for women. Positive correlations were found among the three VISQ and the two CAPS factors: Multimodal Perceptual Alterations and Experiences Associated with the Temporal Lobe.

CONCLUSIONS

The results are consistent with previous findings linking the factors of inner speech with the propensity to auditory hallucination, a phenomenon widely associated with temporal lobe abnormalities. The hallucinations associated with other perceptual systems, however, are still weakly explained.

Exploring the Ecological Validity of Thinking on Demand: Neural Correlates of Elicited vs. Spontaneously Occurring Inner Speech

Psychology and cognitive neuroscience often use standardized tasks to elicit particular experiences. We explore whether elicited experiences are similar to spontaneous experiences. In an MRI scanner, five participants performed tasks designed to elicit inner speech (covertly repeating experimenter-supplied words), inner seeing, inner hearing, feeling, and sensing. Then, in their natural environments, participants were trained in four days of random-beep-triggered Descriptive Experience Sampling (DES). They subsequently returned to the scanner for nine 25-min resting-state sessions; during each they received four DES beeps and described those moments (9 × 4 = 36 moments per participant) of spontaneously occurring experience. Enough of those moments included spontaneous inner speech to allow us to compare brain activation during spontaneous inner speech with what we had found in task-elicited inner speech. ROI analysis was used to compare activation in two relevant areas (Heschl’s gyrus and left inferior frontal gyrus). Task-elicited inner speech was associated with decreased activation in Heschl’s gyrus and increased activation in left inferior frontal gyrus. However, spontaneous inner speech had the opposite effect in Heschl’s gyrus and no significant effect in left inferior frontal gyrus. This study demonstrates how spontaneous phenomena can be investigated in MRI and calls into question the assumption that task-created phenomena are often neurophysiologically and psychologically similar to spontaneously occurring phenomena.

What goes on in the resting-state? A qualitative glimpse into resting-state experience in the scanner

The brain's resting-state has attracted considerable interest in recent years, but currently little is known either about typical experience during the resting-state or about whether there are inter-individual differences in resting-state phenomenology. We used descriptive experience sampling (DES) in an attempt to apprehend high fidelity glimpses of the inner experience of five participants in an extended fMRI study. Results showed that the inner experiences and the neural activation patterns (as quantified by amplitude of low frequency fluctuations analysis) of the five participants were largely consistent across time, suggesting that our extended-duration scanner sessions were broadly similar to typical resting-state sessions. However, there were very large individual differences in inner phenomena, suggesting that the resting-state itself may differ substantially from one participant to the next. We describe these individual differences in experiential characteristics and display some typical moments of resting-state experience. We also show that retrospective characterizations of phenomena can often be very different from moment-by-moment reports. We discuss implications for the assessment of inner experience in neuroimaging studies more generally, concluding that it may be possible to use fMRI to investigate neural correlates of phenomena apprehended in high fidelity.

Inner Speech: Development, Cognitive Functions, Phenomenology, and Neurobiology

Inner speech-also known as covert speech or verbal thinking-has been implicated in theories of cognitive development, speech monitoring, executive function, and psychopathology. Despite a growing body of knowledge on its phenomenology, development, and function, approaches to the scientific study of inner speech have remained diffuse and largely unintegrated. This review examines prominent theoretical approaches to inner speech and methodological challenges in its study, before reviewing current evidence on inner speech in children and adults from both typical and atypical populations. We conclude by considering prospects for an integrated cognitive science of inner speech, and present a multicomponent model of the phenomenon informed by developmental, cognitive, and psycholinguistic considerations. Despite its variability among individuals and across the life span, inner speech appears to perform significant functions in human cognition, which in some cases reflect its developmental origins and its sharing of resources with other cognitive processes.

Assessing the accuracy of self-reported self-talk

As with most kinds of inner experience, it is difficult to assess actual self-talk frequency beyond self-reports, given the often hidden and subjective nature of the phenomenon. The Self-Talk Scale (STS; Brinthaupt et al., 2009) is a self-report measure of self-talk frequency that has been shown to possess acceptable reliability and validity. However, no research using the STS has examined the accuracy of respondents’ self-reports. In the present paper, we report a series of studies directly examining the measurement of self-talk frequency and functions using the STS. The studies examine ways to validate self-reported self-talk by (1) comparing STS responses from 6 weeks earlier to recent experiences that might precipitate self-talk, (2) using experience sampling methods to determine whether STS scores are related to recent reports of self-talk over a period of a week, and (3) comparing self-reported STS scores to those provided by a significant other who rated the target on the STS. Results showed that (1) overall self-talk scores, particularly self-critical and self-reinforcing self-talk, were significantly related to reports of context-specific self-talk; (2) high STS scorers reported talking to themselves significantly more often during recent events compared to low STS scorers, and, contrary to expectations, (3) friends reported less agreement than strangers in their self-other self-talk ratings. Implications of the results for the validity of the STS and for measuring self-talk are presented.

Relations among questionnaire and experience sampling measures of inner speech: a smartphone app study

Inner speech is often reported to be a common and central part of inner experience, but its true prevalence is unclear. Many questionnaire-based measures appear to lack convergent validity and it has been claimed that they overestimate inner speech in comparison to experience sampling methods (which involve collecting data at random timepoints). The present study compared self-reporting of inner speech collected via a general questionnaire and experience sampling, using data from a custom-made smartphone app (Inner Life). Fifty-one university students completed a generalized self-report measure of inner speech (the Varieties of Inner Speech Questionnaire, VISQ) and responded to at least seven random alerts to report on incidences of inner speech over a 2-week period. Correlations and pairwise comparisons were used to compare generalized endorsements and randomly sampled scores for each VISQ subscale. Significant correlations were observed between general and randomly sampled measures for only two of the four VISQ subscales, and endorsements of inner speech with evaluative or motivational characteristics did not correlate at all across different measures. Endorsement of inner speech items was significantly lower for random sampling compared to generalized self-report, for all VISQ subscales. Exploratory analysis indicated that specific inner speech characteristics were also related to anxiety and future-oriented thinking.

The activity view of inner speech

We distinguish two general approaches to inner speech (IS)-the "format" and the "activity" views-and defend the activity view. The format view grounds the utility of IS on features of the representational format of language, and is related to the thesis that the proper function of IS is to make conscious thinking possible. IS appears typically as a product constituted by representations of phonological features. The view also has implications for the idea that passivity phenomena in cognition may be misattributed IS. The activity view sees IS as a speaking activity that does not have a proper function in cognition. It simply inherits the array of functions of outer speech. We argue that it is methodologically advisable to start from this variety of uses, which suggests commonalities between internal and external activities. The format view has several problems; it has to deny "unsymbolized thinking"; it cannot easily explain how IS makes thoughts available to consciousness, and it cannot explain those uses of IS where its format features apparently play no role. The activity view not only lacks these problems but also has explanatory advantages: construing IS as an activity allows it to be integrally constituted by its content; the view is able to construe unsymbolized thinking as part of a continuum of phenomena that exploit the same mechanisms, and it offers a simple explanation for the variety of uses of IS.

Inner experience in the scanner: can high fidelity apprehensions of inner experience be integrated with fMRI?

To provide full accounts of human experience and behavior, research in cognitive neuroscience must be linked to inner experience, but introspective reports of inner experience have often been found to be unreliable. The present case study aimed at providing proof of principle that introspection using one method, descriptive experience sampling (DES), can be reliably integrated with fMRI. A participant was trained in the DES method, followed by nine sessions of sampling within an MRI scanner. During moments where the DES interview revealed ongoing inner speaking, fMRI data reliably showed activation in classic speech processing areas including left inferior frontal gyrus. Further, the fMRI data validated the participant’s DES observations of the experiential distinction between inner speaking and innerly hearing her own voice. These results highlight the precision and validity of the DES method as a technique of exploring inner experience and the utility of combining such methods with fMRI.

Investigating pristine inner experience: implications for experience sampling and questionnaires

We argue that inquiring about directly apprehended ("pristine") inner experience requires four overlapping methodological characteristics: effectively limiting investigation to specific, clearly identified moments; effectively limiting investigation to pristine experience; bracketing presuppositions; and iteratively acquiring skills. We compare and contrast Descriptive Experience Sampling (DES), other (non-DES) experience sampling methods, and questionnaires and conclude that whereas non-DES sampling methods and questionnaires appear to inquire about pristine inner experience, they fall short on all four methodological counts and therefore might be better understood as investigating an ill-defined mixture of presuppositions, judgments about experience, and pristine experience itself. Typical experience sampling studies and questionnaires can be valid and useful, but their validity and utility does not (or at least does not necessarily) arise from their phenomenological fidelity.