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

Ben Alderson-Day,David Smailes,Jamie Moffatt,Kaja Mitrenga,Peter Moseley,Charles Fernyhough

doi:10.1016/j.cortex.2018.12.020

Ben Alderson-Day, David Smailes + Show 4 more

Open Access

https://doi.org/10.1016/j.cortex.2018.12.020

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Abstract

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.

Highlights

Psychosis and psychosis-like experiences have been proposed to occur on a continuum linking clinical and non-clinical populations (Johns & van Os, 2001; Strauss, 1969)
We present an investigation of intentional inhibition, source monitoring, hallucinationproneness and intrusive thoughts in a sample of non-clinical participants
Using a source memory task, we examined whether source monitoring could account for any relations observed between intentional inhibition and hallucination-proneness

Summary

Introduction

Psychosis and psychosis-like experiences have been proposed to occur on a continuum linking clinical and non-clinical populations (Johns & van Os, 2001; Strauss, 1969). It has been argued that a specific problem with “intentional cognitive inhibition” e the ability to consciously and willingly suppress information from working memory e plays an important role in AH (Badcock, Waters, Maybery, & Michie, 2005). Evidence for this has largely come from continuous recognition paradigms such as the Inhibition of Current Irrelevant Memories (ICIM) task (Schnider & Ptak, 1999; Waters, Badcock, Michie, & Maybery, 2006), in which participants must learn to recognise a series of picture targets, ignore the impulse to respond to them on subsequent rounds containing new targets. While healthy participants typically show a directed forgetting effect (i.e., reduced recall for words in “forget” versus “remember” lists; Conway, Harries, Noyes, Racsmany, & Frankish, 2000), participants with schizophrenia forget fewer words (Racsmany et al, 2008) and this correlates with hallucination severity in patients with AH (Soriano, Jimenez, Roman, & Bajo, 2009)

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