A new comparator account of auditory verbal hallucinations: how motor prediction can plausibly contribute to the sense of agency for inner speech

Abstract

The comparator account holds that processes of motor prediction contribute to the sense of agency by attenuating incoming sensory information and that disruptions to this process contribute to misattributions of agency in schizophrenia. Over the last 25 years this simple and powerful model has gained widespread support not only as it relates to bodily actions but also as an account of misattributions of agency for inner speech, potentially explaining the etiology of auditory verbal hallucination (AVH). In this paper we provide a detailed analysis of the traditional comparator account for inner speech, pointing out serious problems with the specification of inner speech on which it is based and highlighting inconsistencies in the interpretation of the electrophysiological evidence commonly cited in its favor. In light of these analyses we propose a new comparator account of misattributed inner speech. The new account follows leading models of motor imagery in proposing that inner speech is not attenuated by motor prediction, but rather derived directly from it. We describe how failures of motor prediction would therefore directly affect the phenomenology of inner speech and trigger a mismatch in the comparison between motor prediction and motor intention, contributing to abnormal feelings of agency. We argue that the new account fits with the emerging phenomenological evidence that AVHs are both distinct from ordinary inner speech and heterogeneous. Finally, we explore the possibility that the new comparator account may extend to explain disruptions across a range of imagistic modalities, and outline avenues for future research.

Emotional self–other voice processing in schizophrenia and its relationship with hallucinations: ERP evidence

“…Abnormalities in the corollary discharge neural mechanism (that codes for the expected sensation, e.g., the sound of one's own voice during speech production, resulting from the action of contracting the muscles of the vocal tract to produce speech; Ford & Mathalon, ) offer a plausible biological explanation for the confusion between self‐generated and externally generated auditory feedback (“Is this my voice or yours?”) in AVH (e.g., Ford & Mathalon, ; Swiney & Sousa, ). ERP studies demonstrated that the activity of the auditory cortex is suppressed to the self‐voice compared to someone else's voice, as reflected in reduced N1 amplitude to self‐generated stimuli (e.g., Heinks‐Maldonado, Mathalon, Gray, & Ford, ).…”

On the Self-Organizing Origins of Agency

“…Yet despite a sizeable literature on ‘the sense of agency’ and its behavioral and neuroimaging correlates (see [1,2] for recent reviews) the scientific basis of causal agency and how we come to experience ourselves as agents is lacking. Agency means action towards an end.…”

The nature of unsymbolized thinking

“…Even though there is no prevalent model of what inner speech is, there is an influential account (see, e.g., Carruthers, 2011;Swiney and Sousa, 2014). According to this account, which draws on research on motor imagery, an inner speech episode is a prediction issued by the forward models, made on the basis of an efference copy of a motor command for speech production, which is at some point aborted.…”