Cognitive and phenomenological characteristics of hallucination-proneness across the lifespan

Thompson, Rhiannon; Moseley, Peter; Alderson-Day, Ben

doi:10.1080/13546805.2020.1850435

Cited by 3 publications

(5 citation statements)

References 43 publications

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“…Advancing age has been correlated with hallucinatory proneness 56 – 58 , which may be associated with the development of age-related diseases that are paired with hallucinations 56 . To test this in our data, we carried out an exploratory analysis looking at the difference between age and our button press measures.…”

Section: Resultsmentioning

confidence: 99%

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Visual hallucinations induced by Ganzflicker and Ganzfeld differ in frequency, complexity, and content

Shenyan,

Lisi,

Greenwood

et al. 2024

Sci Rep

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Visual hallucinations can be phenomenologically divided into those of a simple or complex nature. Both simple and complex hallucinations can occur in pathological and non-pathological states, and can also be induced experimentally by visual stimulation or deprivation—for example using a high-frequency, eyes-open flicker (Ganzflicker) and perceptual deprivation (Ganzfeld). Here we leverage the differences in visual stimulation that these two techniques involve to investigate the role of bottom-up and top-down processes in shifting the complexity of visual hallucinations, and to assess whether these techniques involve a shared underlying hallucinatory mechanism despite their differences. For each technique, we measured the frequency and complexity of the hallucinations produced, utilising button presses, retrospective drawing, interviews, and questionnaires. For both experimental techniques, simple hallucinations were more common than complex hallucinations. Crucially, we found that Ganzflicker was more effective than Ganzfeld at eliciting simple hallucinations, while complex hallucinations remained equivalent across the two conditions. As a result, the likelihood that an experienced hallucination was complex was higher during Ganzfeld. Despite these differences, we found a correlation between the frequency and total time spent hallucinating in Ganzflicker and Ganzfeld conditions, suggesting some shared mechanisms between the two methodologies. We attribute the tendency to experience frequent simple hallucinations in both conditions to a shared low-level core hallucinatory mechanism, such as excitability of visual cortex, potentially amplified in Ganzflicker compared to Ganzfeld due to heightened bottom-up input. The tendency to experience complex hallucinations, in contrast, may be related to top-down processes less affected by visual stimulation.

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Section: Resultsmentioning

confidence: 99%

“…Finally, we also found a positive correlation between age and button-press measures of Ganzfeld hallucinations. Advancing age has been correlated with hallucinatory proneness 56 – 58 , which may reflect age-related upweighting of predictions about the world 64 , 65 , 71 .…”

Section: Discussionmentioning

confidence: 99%

Visual hallucinations induced by Ganzflicker and Ganzfeld differ in frequency, complexity, and content

Shenyan,

Lisi,

Greenwood

et al. 2024

Sci Rep

View full text Add to dashboard Cite

show abstract

“…A positive correlation was found between age and the number and proportional duration of Ganzfeld hallucinations. Advancing age has been correlated with hallucinatory proneness [55][56][57] . One explanation for these findings is the excitability of visual cortex.…”

Section: Discussionmentioning

confidence: 99%

“…Advancing age has been correlated with hallucinatory proneness [55][56][57] , which may be associated with the development of age-related diseases that are paired with hallucinations 55 . To test this in our data, we explored the relationship between age and our button press measures.…”

Section: Hallucinatory Proneness and Agementioning

confidence: 99%

Flicker and Ganzfeld induced visual hallucinations differ in frequency and content

Shenyan

Lisi

Greenwood

et al. 2023

Preprint

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Hallucinatory experiences, defined as perception in the absence of external stimuli, can occur in both pathological and non-pathological states and can be broadly phenomenologically divided into those of a simple and a complex nature. Non-pathological visual hallucinations can be induced experimentally using a variety of stimulation conditions. To assess whether these techniques drive a shared underlying hallucinatory mechanism, despite these differences, we compared two methods: flicker and perceptual deprivation (Ganzfeld). Specifically, we measured the frequency and complexity of the hallucinations produced by these techniques. We utilised button press, retrospective drawing, interviews, and questionnaires to quantify hallucinatory experience in 20 participants. With both experimental techniques, we found that simple hallucinations were more common than complex hallucinations. We also found that on average, flicker was more effective than Ganzfeld at eliciting a higher number of hallucinations, though Ganzfeld hallucinations were longer than flicker hallucinations. There was no interaction between experimental condition and hallucination complexity, suggesting that the increased bottom-up visual input in flicker increased both simple and complex hallucinations similarly. A correlation was observed between the total proportional time spent hallucinating in flicker and Ganzfeld, which was replicated in a retrospective questionnaire measure of experienced intensity, suggesting a shared hallucinatory mechanism between the two methodologies. We attribute these findings to a shared low-level core hallucinatory mechanism, such as excitability of visual cortex, which is amplified in flicker compared to Ganzfeld due to heightened bottom-up input.

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“…Moreover, post-adolescence decreases in both hallucination prevalence (Yates et al, 2021) and proneness (Thompson et al, 2021) continue across the lifespan. By sampling only post-adolescence -or post-developmental risk period -those of higher risk who sought clinical help may be eliminated from the community-based pool.…”

Section: Hallucination Proneness and The Psychosis Continuummentioning

confidence: 99%

A comprehensive study on the cognitive mechanisms and neural substrates of hallucination proneness

Johnson¹

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Cognitive and phenomenological characteristics of hallucination-proneness across the lifespan

Cited by 3 publications

References 43 publications

Visual hallucinations induced by Ganzflicker and Ganzfeld differ in frequency, complexity, and content

Visual hallucinations induced by Ganzflicker and Ganzfeld differ in frequency, complexity, and content

Flicker and Ganzfeld induced visual hallucinations differ in frequency and content

A comprehensive study on the cognitive mechanisms and neural substrates of hallucination proneness

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