Examining the relationships between cognition and auditory hallucinations: A systematic review.

OBJECTIVE: Auditory hallucinations (hearing voices) have been associated with a range of altered cognitive functions, pertaining to signal detection, source-monitoring, memory, inhibition and language processes. Yet, empirical results are inconsistent. Despite this, several theoretical models of auditory hallucinations persist, alongside increasing emphasis on the utility of a multidimensional framework. Thus, clarification of current evidence across the broad scope of proposed mechanisms is warranted. METHOD: A systematic search of the Web of Science, PubMed and Scopus databases was conducted. Records were screened to confirm the use of an objective behavioural cognitive task, and valid measurement of hallucinations specific to the auditory modality. RESULTS: Auditory hallucinations were primarily associated with difficulties in perceptual decision-making (i.e. reduced sensitivity/accuracy for signal-noise discrimination; liberal responding to ambiguity), source-monitoring (i.e. self-other and temporal context confusion), working memory and language function (i.e. reduced verbal fluency). Mixed or limited support was observed for perceptual feature discrimination, imagery vividness/illusion susceptibility, source-monitoring for stimulus form and spatial context, recognition and recall memory, executive functions (e.g. attention, inhibition), emotion processing and language comprehension/hemispheric organisation. CONCLUSIONS: Findings were considered within predictive coding and self-monitoring frameworks. Of concern was the portion of studies which - despite offering auditory-hallucination-specific aims and inferences - employed modality-general measures, and/or diagnostic-based contrasts with psychologically healthy individuals. This review highlights disparities within the literature between theoretical conceptualisations of auditory hallucinations and the body of rigorous empirical evidence supporting such inferences. Future cognitive investigations, beyond the schizophrenia-spectrum, which explicitly define and measure the timeframe and sensory modality of hallucinations, are recommended.

Non-clinical hallucinations and mental imagery across sensory modalities.

INTRODUCTION: Vivid mental imagery has been proposed to increase the likelihood of experiencing hallucinations. Typically, studies have employed a modality general approach to mental imagery which compares imagery across multiple domains (e.g., visual, auditory and tactile) to hallucinations in multiple senses. However, modality specific imagery may be a better predictor of hallucinations in the same domain. The study examined the contribution of imagery to hallucinations in a non-clinical sample and specifically whether imagery best predicted hallucinations at a modality general or modality specific level. METHODS: In study one, modality general and modality specific accounts of the imagery-hallucination relationship were contrasted through application of self-report measures in a sample of 434 students. Study two used a subsample (n = 103) to extend exploration of the imagery-hallucinations relationship using a performance-based imagery task. RESULTS: A small to moderate modality general relationship was observed between self-report imagery and hallucination proneness. There was only evidence of a modality specific relationship in the tactile domain. Performance-based imagery measures were unrelated to hallucinations and self-report imagery. CONCLUSIONS: Mental imagery may act as a modality general process increasing hallucination proneness. The observed distinction between self-report and performance-based imagery highlights the difficulty of accurately measuring internal processes.

Varieties of felt presence? Three surveys of presence phenomena and their relations to psychopathology.

BACKGROUND: Experiences of felt presence (FP) are well documented in neurology, neuropsychology and bereavement research, but systematic research in relation to psychopathology is limited. FP is a feature of sensorimotor disruption in psychosis, hypnagogic experiences, solo pursuits and spiritual encounters, but research comparing these phenomena remains rare. A comparative approach to the phenomenology of FP has the potential to identify shared and unique processes underlying the experience across these contexts, with implications for clinical understanding and intervention. METHODS: We present a mixed-methods analysis from three online surveys comparing FP across three diverse contexts: a population sample which included people with experience of psychosis and voice-hearing (study 1, N = 75), people with spiritual and spiritualist beliefs (study 2, N = 47) and practitioners of endurance/solo pursuits (study 3, N = 84). Participants were asked to provide descriptions of their FP experiences and completed questionnaires on FP frequency, hallucinatory experiences, dissociation, paranoia, social inner speech and sleep. Data and code for the study are available via OSF. RESULTS: Hierarchical linear regression analysis indicated that FP frequency was predicted by a general tendency to experience hallucinations in all three studies, although paranoia and gender (female > male) were also significant predictors in sample 1. Qualitative analysis highlighted shared and diverging phenomenology of FP experiences across the three studies, including a role for immersive states in FP. CONCLUSIONS: These data combine to provide the first picture of the potential shared mechanisms underlying different accounts of FP, supporting a unitary model of the experience.

Measurement practices in hallucinations research.

Introduction: In several sub-fields of psychology, there has been a renewed focus on measurement practices. As far as we are aware, this has been absent in hallucinations research. Thus, we investigated (a) cross-study variation in how hallucinatory experiences are measured and (b) the reliability of measurements obtained using two tasks that are widely employed in hallucinations research.Method: In Study 1, we investigated to what extent there was variation in how the Launay-Slade Hallucination Scale (LSHS) has been used across 100 studies. In Study 2, we investigated the reliability of the measurements obtained through source monitoring and signal detection tasks, using data from four recent publications. Materials/data are available at doi: 10.17605/osf.io/d3gnk/.Results: In Study 1, we found substantial variation in how hallucinatory experiences were assessed using the LSHS and that descriptions of the LSHS were often incomplete in important ways. In Study 2, we reported a range of reliability estimates for the measurements obtained using source monitoring and signal discrimination tasks. Some measurements obtained using source monitoring tasks had unacceptably low levels of reliability.Conclusions: Our findings suggest that suboptimal measurement practices are common in hallucinations research and we suggest steps researchers could take to improve measurement practices.

Correlates of Hallucinatory Experiences in the General Population: An International Multisite Replication Study.

Hallucinatory experiences can occur in both clinical and nonclinical groups. However, in previous studies of the general population, investigations of the cognitive mechanisms underlying hallucinatory experiences have yielded inconsistent results. We ran a large-scale preregistered multisite study, in which general-population participants (N = 1,394 across 11 data-collection sites and online) completed assessments of hallucinatory experiences, a measure of adverse childhood experiences, and four tasks: source memory, dichotic listening, backward digit span, and auditory signal detection. We found that hallucinatory experiences were associated with a higher false-alarm rate on the signal detection task and a greater number of reported adverse childhood experiences but not with any of the other cognitive measures employed. These findings are an important step in improving reproducibility in hallucinations research and suggest that the replicability of some findings regarding cognition in clinical samples needs to be investigated.

Cognitive and phenomenological characteristics of hallucination-proneness across the lifespan.

INTRODUCTION: The impact of age on hallucination-proneness within healthy adult cohorts and its relation to underlying cognitive mechanisms is underexplored. Based on previously researched trends in relation to cognitive ageing, we hypothesised that older and younger adults, when compared to a middle adult age group, would show differential relations between hallucination-proneness and cognitive performance. METHODS: A mixed methods, between-groups study was conducted with 30 young adults, 26 older adults, and 27 from a "middle adulthood" group. Participants completed a source memory task, jumbled speech task, Launay-Slade hallucination scale, unusual experiences schedule, and control measures of delusion-proneness and attitudes to mental health. RESULTS: Compared to older age-groups, younger participants demonstrated better scores on the source memory task, and reported hearing more words in jumbled speech. Additionally, younger cohorts rated higher on hallucination-proneness and disclosed more unusual experiences on a customised schedule designed to gather further qualitative data. Jumbled speech scores positively correlated with hallucination-proneness scores, particularly for the "middle" age group. Source memory performance unexpectedly correlated positively with hallucination-proneness, although this may be the product of age differences in task performance. CONCLUSIONS: Age differences in hallucination-proneness are evident on self-report and cognitive measures. Implications are discussed for potentially non-overlapping cognitive mechanisms underlying hallucination-proneness in non-clinical groups.

A linguistic approach to the psychosis continuum: (dis)similarities and (dis)continuities in how clinical and non-clinical voice-hearers talk about their voices.

Introduction: "Continuum" approaches to psychosis have generated reports of similarities and differences in voice-hearing in clinical and non-clinical populations at the cohort level, but not typically examined overlap or degrees of difference between groups. Methods: We used a computer-aided linguistic approach to explore reports of voice-hearing by a clinical group (Early Intervention in Psychosis service-users; N = 40) and a non-clinical group (spiritualists; N = 27). We identify semantic categories of terms statistically overused by one group compared with the other, and by each group compared to a control sample of non-voice-hearing interview data (log likelihood (LL) value 6.63+=p < .01; effect size measure: log ratio 1.0+). We consider whether individual values support a continuum model. Results: Notwithstanding significant cohort-level differences, there was considerable continuity in language use. Reports of negative affect were prominent in both groups (p < .01, log ratio: 1.12+). Challenges of cognitive control were also evident in both cohorts, with references to "disengagement" accentuated in service-users (p < .01, log ratio: 1.14+). Conclusion: A corpus linguistic approach to voice-hearing provides new evidence of differences between clinical and non-clinical groups. Variability at the individual level provides substantial evidence of continuity with implications for cognitive mechanisms underlying voice-hearing.

Musical hallucinations, musical imagery, and earworms: A new phenomenological survey.

Musical hallucinations (MH) account for a significant proportion of auditory hallucinations, but there is a relative lack of research into their phenomenology. In contrast, much research has focused on other forms of internally generated musical experience, such as earworms (involuntary and repetitive inner music), showing that they can vary in perceived control, repetitiveness, and in their effect on mood. We conducted a large online survey (N = 270), including 44 participants with MH, asking participants to rate imagery, earworms, or MH on several variables. MH were reported as occurring less frequently, with less controllability, less lyrical content, and lower familiarity, than other forms of inner music. MH were also less likely to be reported by participants with higher levels of musical expertise. The findings are outlined in relation to other forms of hallucinatory experience and inner music, and their implications for psychological models of hallucinations discussed.

Learning to Discern the Voices of Gods, Spirits, Tulpas, and the Dead.

There are communities in which hearing voices frequently is common and expected, and in which participants are not expected to have a need for care. This paper compares the ideas and practices of these communities. We observe that these communities utilize cultural models to identify and to explain voice-like events-and that there are some common features to these models across communities. All communities teach participants to "discern," or identify accurately, the legitimate voice of the spirit or being who speaks. We also observe that there are roughly two methods taught to participants to enable them to experience spirits (or other invisible beings): trained attention to inner experience, and repeated speech to the invisible other. We also observe that all of these communities model a learning process in which the ability to hear spirit (or invisible others) becomes more skilled with practice, and in which what they hear becomes clearer over time. Practice-including the practice of discernment-is presumed to change experience. We also note that despite these shared cultural ideas and practices, there is considerable individual variation in experience-some of which may reflect psychotic process, and some perhaps not. We suggest that voice-like events in this context may be shaped by cognitive expectation and trained practice as well as an experiential pathway. We also suggest that researchers could explore these common features both as a way to help those struggling with psychosis, and to consider the possibility that expectations and practice may affect the voice-hearing experience.

Speech Illusions in People at Clinical High Risk for Psychosis Linked to Clinical Outcome.

BACKGROUND AND HYPOTHESIS: Around 20% of people at clinical high risk (CHR) for psychosis later develop a psychotic disorder, but it is difficult to predict who this will be. We assessed the incidence of hearing speech (termed speech illusions [SIs]) in noise in CHR participants and examined whether this was associated with adverse clinical outcomes. STUDY DESIGN: At baseline, 344 CHR participants and 67 healthy controls were presented with a computerized white noise task and asked whether they heard speech, and whether speech was neutral, affective, or whether they were uncertain about its valence. After 2 years, we assessed whether participants transitioned to psychosis, or remitted from the CHR state, and their functioning. STUDY RESULTS: CHR participants had a lower sensitivity to the task. Logistic regression revealed that a bias towards hearing targets in stimuli was associated with remission status (OR = 0.21, P = 042). Conversely, hearing SIs with uncertain valence at baseline was associated with reduced likelihood of remission (OR = 7.72. P = .007). When we assessed only participants who did not take antipsychotic medication at baseline, the association between hearing SIs with uncertain valence at baseline and remission likelihood remained (OR = 7.61, P = .043) and this variable was additionally associated with a greater likelihood of transition to psychosis (OR = 5.34, P = .029). CONCLUSIONS: In CHR individuals, a tendency to hear speech in noise, and uncertainty about the affective valence of this speech, is associated with adverse outcomes. This task could be used in a battery of cognitive markers to stratify CHR participants according to subsequent outcomes.

Voice-Hearing Across The Continuum: A Phenomenology of Spiritual Voices.

BACKGROUND AND HYPOTHESIS: Voice-hearing in clinical and nonclinical groups has previously been compared using standardized assessments of psychotic experiences. Findings from several studies suggest that nonclinical voice-hearing is distinguished by reduced distress and increased control. However, symptom-rating scales developed for clinical populations may be limited in their ability to elucidate subtle aspects of nonclinical voices. Moreover, such experiences often occur within specific contexts and belief systems, such as spiritualism. We investigated similarities and differences in the phenomenology of clinical voice-hearing and nonclinical voice-hearer (NCVH). STUDY DESIGN: We conducted a comparative interdisciplinary study which administered a semi-structured interview to NCVH individuals (N = 26) and psychosis patients (N = 40). The nonclinical group was recruited from spiritualist communities. We used content analysis and inductive thematic analysis to create a coding frame which was used across both spiritual and patient groups to compare phenomenological features of voice-hearing. STUDY RESULTS: The findings were consistent with previous results regarding distress and control. Additionally, in the NCVH group, multiple modalities were often integrated into 1 entity, and there were high levels of associated visual imagery, and subtle differences in the location of voices relating to perceptual boundaries. Most NCVHs reported voices before encountering spiritualism, suggesting that their onset was not solely due to deliberate practice. CONCLUSIONS: Nonclinical spiritual voice-hearing has important similarities and differences to voices in psychosis. Future research should aim to understand how spiritual voice-hearers cultivate and control voice-hearing after its onset, which may inform interventions for people with psychosis with distressing voices.

Continuities and Discontinuities in the Cognitive Mechanisms Associated With Clinical and Nonclinical Auditory Verbal Hallucinations.

Auditory verbal hallucinations (AVHs) are typically associated with schizophrenia but also occur in individuals without any need for care (nonclinical voice hearers [NCVHs]). Cognitive models of AVHs posit potential biases in source monitoring, top-down processes, or a failure to inhibit intrusive memories. However, research across clinical/nonclinical groups is limited, and the extent to which there may be continuity in cognitive mechanism across groups, as predicted by the psychosis-continuum hypothesis, is unclear. We report two studies in which voice hearers with psychosis (n = 31) and NCVH participants reporting regular spiritual voices (n = 26) completed a battery of cognitive tasks. Compared with non-voice-hearing groups (ns = 33 and 28), voice hearers with psychosis showed atypical performance on signal detection, dichotic listening, and memory-inhibition tasks but intact performance on the source-monitoring task. NCVH participants, however, showed only atypical signal detection, which suggests differences between clinical and nonclinical voice hearers potentially related to attentional control and inhibition. These findings suggest that at the level of cognition, continuum models of hallucinations may need to take into account continuity but also discontinuity between clinical and nonclinical groups.

Voice-Hearing and Personification: Characterizing Social Qualities of Auditory Verbal Hallucinations in Early Psychosis.

Recent therapeutic approaches to auditory verbal hallucinations (AVH) exploit the person-like qualities of voices. Little is known, however, about how, why, and when AVH become personified. We aimed to investigate personification in individuals' early voice-hearing experiences. We invited Early Intervention in Psychosis (EIP) service users aged 16-65 to participate in a semistructured interview on AVH phenomenology. Forty voice-hearers (M = 114.13 days in EIP) were recruited through 2 National Health Service trusts in northern England. We used content and thematic analysis to code the interviews and then statistically examined key associations with personification. Some participants had heard voices intermittently for multiple years prior to clinical involvement (M = 74.38 months), although distressing voice onset was typically more recent (median = 12 months). Participants reported a range of negative emotions (predominantly fear, 60%, 24/40, and anxiety, 62.5%, 26/40), visual hallucinations (75%, 30/40), bodily states (65%, 25/40), and "felt presences" (52.5%, 21/40) in relation to voices. Complex personification, reported by a sizeable minority (16/40, 40%), was associated with experiencing voices as conversational (odds ratio [OR] = 2.56) and companionable (OR = 3.19) but not as commanding or trauma-related. Neither age of AVH onset nor time since onset related to personification. Our findings highlight significant personification of AVH even at first clinical presentation. Personified voices appear to be distinguished less by their intrinsic properties, commanding qualities, or connection with trauma than by their affordances for conversation and companionship.

Item-specific overlap between hallucinatory experiences and cognition in the general population: A three-step multivariate analysis of international multi-site data.

Hallucinatory experiences (HEs) can be pronounced in psychosis, but similar experiences also occur in nonclinical populations. Cognitive mechanisms hypothesized to underpin HEs include dysfunctional source monitoring, heightened signal detection, and impaired attentional processes. Using data from an international multisite study on non-clinical participants (N = 419), we described the overlap between two sets of variables - one measuring cognition and the other HEs - at the level of individual items. We used a three-step method to extract and examine item-specific signal, which is typically obscured when summary scores are analyzed using traditional methodologies. The three-step method involved: (1) constraining variance in cognition variables to that which is predictable from HE variables, followed by dimension reduction, (2) determining reliable HE items using split-halves and permutation tests, and (3) selecting cognition items for interpretation using a leave-one-out procedure followed by repetition of Steps 1 and 2. The results showed that the overlap between HEs and cognition variables can be conceptualized as bi-dimensional, with two distinct mechanisms emerging as candidates for separate pathways to the development of HEs: HEs involving perceptual distortions on one hand (including voices), underpinned by a low threshold for signal detection in cognition, and HEs involving sensory overload on the other hand, underpinned by reduced laterality in cognition. We propose that these two dimensions of HEs involving distortions/liberal signal detection, and sensation overload/reduced laterality may map onto psychosis-spectrum and dissociation-spectrum anomalous experiences, respectively.

Inner experience differs in rumination and distraction without a change in electromyographical correlates of inner speech.

Ruminative thought is a style of thinking which involves repetitively focusing upon one's own negative mood, its causes and its consequences. The negative effects of rumination are well-documented, but comparatively little is known about how rumination is experienced. The evaluative nature of rumination suggests that it could involve more inner speech than non-ruminative states. The present study (N = 31) combined facial electromyography and self-report questionnaires to determine the type of inner experience that occurs in rumination. The results showed that induced rumination involved similar levels of muscle activity related to inner speech as periods of induced distraction. However, experience sampling and questionnaire responses showed that rumination involved more verbal thought, and also involved more evaluative and dialogic inner speech than distraction. These findings contribute to the understanding of inner speech as a flexible phenomenon and confirms the importance of employing multiple methods to investigate inner speech. Future research should clarify the link between inner speech in rumination and its negative effects on wellbeing.

Intentional inhibition but not source memory is related to hallucination-proneness and intrusive thoughts in a university sample.

Proneness to unusual perceptual states - such as auditory or visual hallucinations - has been proposed to exist on a continuum in the general population, but whether there is a cognitive basis for such a continuum remains unclear. Intentional cognitive inhibition (the ability to wilfully control thoughts and memories) is one mechanism that has been linked to auditory hallucination susceptibility, but most evidence to date has been drawn from clinical samples only. Moreover, such a link has yet to be demonstrated over and above relations to other cognitive skills (source monitoring) and cognitive states (intrusive thoughts) that often correlate with both inhibition and hallucinations. The present study deployed two tests of intentional inhibition ability - the Inhibition of Currently Irrelevant Memories (ICIM) task and Directed Forgetting (DF) task - and one test of source monitoring (a source memory task) to examine how cognitive task performance relates to self-reported i) auditory hallucination-proneness and ii) susceptibility to intrusive thoughts in a non-clinical student sample (N = 76). Hierarchical regression analyses were used to assess the independent and combined contributions of task performance to proneness scores. ICIM performance but not DF or source memory scores were significantly related to both hallucination-proneness and intrusive thoughts. Further analysis suggested that intrusive thoughts may mediate the link between intentional inhibition skills and auditory hallucination-proneness, suggesting a potential pathway from inhibition to perception via intrusions in cognition. The implications for studying cognitive mechanisms of hallucination and their role in "continuum" views of psychosis-like experiences are discussed.

Reading characters in voices: Ratings of personality characteristics from voices predict proneness to auditory verbal hallucinations.

People rapidly make first impressions of others, often based on very little information-minimal exposure to faces or voices is sufficient for humans to make up their mind about personality of others. While there has been considerable research on voice personality perception, much less is known about its relevance to hallucination-proneness, despite auditory hallucinations being frequently perceived as personified social agents. The present paper reports two studies investigating the relation between voice personality perception and hallucination-proneness in non-clinical samples. A voice personality perception task was created, in which participants rated short voice recordings on four personality characteristics, relating to dimensions of the voice's perceived Valence and Dominance. Hierarchical regression was used to assess contributions of Valence and Dominance voice personality ratings to hallucination-proneness scores, controlling for paranoia-proneness and vividness of mental imagery. Results from Study 1 suggested that high ratings of voices as dominant might be related to high hallucination-proneness; however, this relation seemed to be dependent on reported levels of paranoid thinking. In Study 2, we show that hallucination-proneness was associated with high ratings of voice dominance, and this was independent of paranoia and imagery abilities scores, both of which were found to be significant predictors of hallucination-proneness. Results from Study 2 suggest an interaction between gender of participants and the gender of the voice actor, where only ratings of own gender voices on Dominance characteristics are related to hallucination-proneness scores. These results are important for understanding the perception of characterful features of voices and its significance for psychopathology.

Experimentally induced limb-disownership in mixed reality.

The seemingly stable construct of our bodily self depends on the continued, successful integration of multisensory feedback about our body, rather than its purely physical composition. Accordingly, pathological disruption of such neural processing is linked to striking alterations of the bodily self, ranging from limb misidentification to disownership, and even the desire to amputate a healthy limb. While previous embodiment research has relied on experimental setups using supernumerary limbs in variants of the Rubber Hand Illusion, we here used Mixed Reality to directly manipulate the feeling of ownership for one's own, biological limb. Using a Head-Mounted Display, participants received visual feedback about their own arm, from an embodied first-person perspective. In a series of three studies, in independent cohorts, we altered embodiment by providing visuotactile feedback that could be synchronous (control condition) or asynchronous (400 ms delay, Real Hand Illusion). During the illusion, participants reported a significant decrease in ownership of their own limb, along with a lowered sense of agency. Supporting the right-parietal body network, we found an increased illusion strength for the left upper limb as well as a modulation of the feeling of ownership during anodal transcranial direct current stimulation. Extending previous research, these findings demonstrate that a controlled, visuotactile conflict about one's own limb can be used to directly and systematically modulate ownership - without a proxy. This not only corroborates the malleability of body representation but questions its permanence. These findings warrant further exploration of combined VR and neuromodulation therapies for disorders of the bodily self.

Imaginary Companions, Inner Speech, and Auditory Verbal Hallucinations: What Are the Relations?

Interacting with imaginary companions (ICs) is now considered a natural part of childhood for many children, and has been associated with a range of positive developmental outcomes. Recent research has explored how the phenomenon of ICs in childhood and adulthood relates to the more unusual experience of hearing voices (or auditory verbal hallucinations, AVH). Specifically, parallels have been drawn between the varied phenomenology of the two kinds of experience, including the issues of quasi-perceptual vividness and autonomy/control. One line of research has explored how ICs might arise through the internalization of linguistically mediated social exchanges to form dialogic inner speech. We present data from two studies on the relation between ICs in childhood and adulthood and the experience of inner speech. In the first, a large community sample of adults (N = 1,472) completed online the new Varieties of Inner Speech - Revised (VISQ-R) questionnaire (Alderson-Day et al., 2018) on the phenomenology of inner speech, in addition to providing data on ICs and AVH. The results showed differences in inner speech phenomenology in individuals with a history of ICs, with higher scores on the Dialogic, Evaluative, and Other Voices subscales of the VISQ-R. In the second study, a smaller community sample of adults (N = 48) completed an auditory signal detection task as well as providing data on ICs and AVH. In addition to scoring higher on AVH proneness, individuals with a history of ICs showed reduced sensitivity to detecting speech in white noise as well as a bias toward detecting it. The latter finding mirrored a pattern previously found in both clinical and nonclinical individuals with AVH. These findings are consistent with the view that ICs represent a hallucination-like experience in childhood and adulthood which shows meaningful developmental relations with the experience of inner speech.

Beyond Trauma: A Multiple Pathways Approach to Auditory Hallucinations in Clinical and Nonclinical Populations.

That trauma can play a significant role in the onset and maintenance of voice-hearing is one of the most striking and important developments in the recent study of psychosis. Yet the finding that trauma increases the risk for hallucination and for psychosis is quite different from the claim that trauma is necessary for either to occur. Trauma is often but not always associated with voice-hearing in populations with psychosis; voice-hearing is sometimes associated with willful training and cultivation in nonclinical populations. This article uses ethnographic data among other data to explore the possibility of multiple pathways to voice-hearing for clinical and nonclinical individuals whose voices are not due to known etiological factors such as drugs, sensory deprivation, epilepsy, and so forth. We suggest that trauma sometimes plays a major role in hallucinations, sometimes a minor role, and sometimes no role at all. Our work also finds seemingly distinct phenomenological patterns for voice-hearing, which may reflect the different salience of trauma for those who hear voices.