The multifaceted nature of inner speech: Phenomenology, neural correlates, and implications for aphasia and psychopathology
M. Dahò, D. Monzani
Cognitive Neuropsychology February 17, 2025 DOI: 10.1080/02643294.2025.2527983 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Narrative review Peer reviewed |
|---|---|
| Topics | Philosophy of mind |
| Key findings | The authors propose a four-part classification of inner speech (monologic, dialogal, elicited, spontaneous) and report that dialogal forms engage Theory of Mind networks, elicited inner speech activates the left inferior frontal gyrus, and spontaneous inner speech engages Heschl's gyrus. They argue that inner speech may be partially preserved in aphasia, suggesting a rehabilitation pathway. |
Abstract
ABSTRACT This narrative review explores the phenomenon of inner speech – mental speech without visible articulation – and its implications for cognitive science and clinical practice. Despite its importance, the many neural mechanisms underlying inner speech remain unclear. We propose classifying inner speech into monologic, dialogal, elicited, and spontaneous forms, and discuss related phenomenological and neural correlates theories. A literature review on PubMed (1990–2024) identified 83 studies. Dialogal forms recruit Theory of Mind networks, compared to monologic forms. Task-elicited inner speech activates the left inferior frontal gyrus more strongly, while spontaneous inner speech engages Heschl’s gyrus, suggesting auditory involvement. Evidence regarding aphasia suggests inner speech may be partially preserved even when overt speech is impaired, offering a potential route for rehabilitation. Future research should also address the emotional aspects of inner speech, its role in psychopathology, and its developmental trajectory. Such studies may improve interventions for disorders related to dysfunctional inner speech. Abbreviation: ACC: anterior cingulate cortex; ALE: activation likelihood estimation; AVH: auditory verbal hallucination; BMI: brain-machine interface; CD: corollary discharge; ConDialInt: consciousness-dialogue-intentionality; DES: descriptive experience sampling; DTI: diffusion tensor imaging; dPMC: dorsal premotor cortex; dmPFC: dorsomedial prefrontal cortex; IFG: inferior frontal gyrus; M1: primary motor cortex; MedFG: medial frontal gyrus; MFG: middle frontal gyrus; MTG: middle temporal gyrus; MRI: magnetic resonance imaging; preSMA: presupplementary motor area; PrG: precentral gyrus; SMA: supplementary motor area; SMG: supramarginal gyrus; SPC: superior parietal cortex; SPL: superior parietal lobule; STG: superior temporal gyrus; STS: superior temporal sulcus; TVA: temporal vocal areas; ToM: theory of mind; vmPFC: ventromedial prefrontal cortex
Comparable studies
Other narrative reviews on philosophy of mind, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Body Consciousness: A Philosophy of Mindfulness and Somaesthetics | 2008 | Review article | |
| Phenomenology, Structure, and Dynamic of Psychedelic States | 2016 | Review | |
| Classic Hallucinogens and Mystical Experiences: Phenomenology and Neural Correlates. | 2018 | Review | |
| The lived experience of psychosis: a bottom-up review co-written by experts by experience and academics. Individuals with lived experience of psychosis, family members, and carers | 2022 | Co-written bottom-up review | |
| From autopoiesis to neurophenomenology: Francisco Varela's exploration of the biophysics of being. | 2003 | Review |
Citations in the library
Cited by 1
Cites 5
- Inner speech and the body error theory. Frontiers in Psychology 2024
- Inner speech as language process and cognitive tool. Trends in Cognitive Sciences December 2023
- Bridging phenomenology and neural mechanisms of inner speech: ALE meta-analysis on egocentricity and spontaneity in a dual-mechanistic framework. Neuroimage November 15, 2023
- Abstract Concepts and the Embodied Mind April 13, 2022
- Inner Speech: Development, Cognitive Functions, Phenomenology, and Neurobiology Psychological Bulletin May 25, 2015