Externalizing biases and hallucinations in source-monitoring, self-monitoring and signal detection studies: a meta-analytic review

Abstract

The findings suggest that externalizing biases are important cognitive underpinnings of hallucinatory experiences. Clinical interventions targeting these biases should be explored as possible treatments for clients with distressing voices.

Associations between intrusive thoughts, reality discrimination and hallucination-proneness in healthy young adults

“…The relation between reality discrimination problems and AH-proneness reported here is concordant with a number of analogue (e.g., Barkus et al, 2007) and clinical studies (e.g., Varese, Barkus, & Bentall, 2012), as well as a recent meta-analysis that synthesized this data (Brookwell et al, 2013). Together, these findings support the argument that people who experience AH tend to misattribute internal, self-generated events to an external, non-self source, a claim that is central to most models of AH (e.g., Bentall, 1990;Waters et al, 2013).…”

“…Presumably, when a false alarm occurs, participants have mistaken their internal representation of the signal (the speech) for the external signal. A recent meta-analysis (Brookwell, Varese, & Bentall, 2013) has shown that psychotic participants who experience AH, and non-clinical participants who are prone to AH, have biased reality discrimination, so that they make more false alarms than do control participants when performing these tasks, suggesting that they have a tendency to misattribute internally-generated events to an external source. Bentall (2003) has argued that a person who experiences high levels of intrusive thoughts and has poor reality discrimination abilities should be especially prone to AH, as they will frequently experience cognitions that lack the characteristics of self-generated events, and they will be predisposed towards mistaking internal, self-generated events for external, other-generated events.…”

The impact of negative affect on reality discrimination

“…Presumably, when a false alarm occurs, participants have mistaken their internal, self-generated representation of the speech for the external, 'real' speech. Consistent with current models, when performing a SDT, patients who experience AH show an externalizing bias, whereby they are more likely than controls to report that speech is present in the noise, even when it is absent (e.g., Bentall & Slade, 1985;Varese et al, 2012;Vercammen, de Haan, & Aleman, 2008;Brookwell, Bentall, & Varese, 2012).…”

Developing schizophrenia

“…Conversely, Garety et al (2005) used measures of reasoning, emotion, belief inflexibility and extreme responding to demonstrate that people with delusional beliefs displayed evidence of the cognitive bias of 'jumping to conclusions'. Likewise, a meta-analysis of externalising biases in people experiencing auditory hallucinations (Brookwell, Bentall, & Varese, 2013) found robust, moderate to large effects associating these experiences with cognitive impairments in source monitoring (i.e. attributing self-generated 'inner speech' to an external source).…”