Scientific Reports
November 16, 2017
Keisuke Suzuki, Warrick Roseboom, David J. Schwartzman et al.
111 citations
The Hallucination Machine combines deep convolutional neural networks with panoramic virtual reality to simulate visual hallucinatory experiences without drugs or psychosis. In one experiment, the system induced visual phenomenology similar to classical psychedelics. In a second experiment, the simulated hallucinations did not produce the temporal distortion typically linked to altered states. This tool allows researchers to study altered consciousness without the confounding physiological and cognitive effects of psychoactive substances or psychopathological conditions.
bioRxiv (Cold Spring Harbor Laboratory)
January 4, 2019
David J. Schwartzman, Michael Schartner, Benjamin B. Ador et al.
31 citations
preprint
Stroboscopic stimulation—flashing light—can induce altered states of consciousness without drugs, increasing the intensity and range of subjective experiences, including simple and complex visual hallucinations. These experiences were accompanied by rises in EEG signal diversity, measured by Lempel-Ziv complexity, that exceeded levels seen during wakeful rest. The results align with previous findings from psychedelic studies and support the idea that neural signal diversity reflects the richness of subjective experience across different states of consciousness.
Frontiers in Human Neuroscience
January 3, 2024
Keisuke Suzuki, Anil K. Seth, David J. Schwartzman
20 citations
Visual hallucinations differ substantially depending on their cause, such as neurodegenerative disease, visual loss, or psychedelic drugs. Using a deep neural network approach called computational (neuro)phenomenology, researchers identified three key dimensions that distinguish these hallucinations: realism (how true-to-life they seem), spontaneity (how much they depend on sensory input), and complexity. By tuning the network along these dimensions, they generated synthetic hallucinations characteristic of each cause. Two studies with patients having Parkinson's disease, Lewy body dementia, or Charles Bonnet syndrome, and people with recent psychedelic experience, confirmed that these synthetic images matched the phenomenology reported by each group. The findings show that a neural network model can capture the distinctive visual features of hallucinations from different origins.
Philosophical transactions of the Royal Society of London. Series B, Biological sciences
December 9, 2019
David J. Schwartzman, Daniel Bor, Nicolas Rothen et al.
7 citations
Synaesthesia, where specific stimuli automatically trigger additional perceptual experiences, offers insight into conscious perception. While traditionally considered congenital, growing evidence shows that synaesthesia-like experiences can be induced in non-synaesthetes, even in adulthood. This review examines various methods for artificially inducing such experiences and compares them to natural synaesthesia's hallmarks: consistency, automaticity, and lack of 'perceptual presence'. The authors conclude that many aspects of synaesthesia can be induced, suggesting developmental and learning components in its acquisition and extending evidence of perceptual plasticity in adults.
bioRxiv Preprint Server
August 3, 2020
David J. Schwartzman, Aleš Oblak, Nicolas Rothen et al.
4 citations
preprint
Grapheme-colour synaesthesia (GCS) involves automatic, consistent colour experiences triggered by letters or numbers. Two recent studies showed that extensive associative training can produce behavioural, neurophysiological, and phenomenological markers of synaesthesia in non-synaesthetes, but they did not deeply compare the induced experiences to natural synaesthesia. This study analyzed interview transcripts from participants who underwent such training and from natural synaesthetes. Both groups shared several experiential categories, including stability, location, shape, relative strength, and automaticity of colour experience. However, automaticity differed significantly: natural synaesthetes mostly reported automatic experiences, while induced synaesthesia-like experiences were mostly described as wilful. Additional categories emerged only in natural synaesthetes, highlighting heterogeneity. The results indicate that intensive training can alter conscious perception, producing phenomenology substantially resembling natural synaesthesia.
Neurosci Conscious
April 7, 2026
Romy Beauté, David J. Schwartzman, Guillaume Dumas et al.
3 citations
No Summary
bioRxiv Preprint Server
November 3, 2017
Keisuke Suzuki, Warrick Roseboom, David J. Schwartzman et al.
2 citations
preprint
A tool called the Hallucination Machine simulates visual hallucinatory experiences using deep convolutional neural networks and panoramic virtual reality videos of natural scenes. It induces visual phenomenology qualitatively similar to classical psychedelics, but does not evoke the temporal distortion commonly associated with altered states. This technique allows researchers to study altered consciousness without the confounding physiological and cognitive effects of psychoactive substances or psychopathological conditions, offering a valuable method for consciousness science and psychiatry.
bioRxiv (Cold Spring Harbor Laboratory)
February 18, 2026
Ethan Grove, Trevor Hewitt, Anil K. Seth et al.
1 citation
Visual hallucinations (VHs) occur in psychedelic states and various psychiatric and neurological conditions, but their phenomenology is hard to characterize due to a lack of large-scale datasets. Stroboscopic light stimulation (SLS) with closed eyes reliably induces VHs in healthy people, producing vivid colors and dynamic geometric patterns similar to simple VHs in other contexts. Researchers developed an unsupervised computer-vision pipeline to analyze 10,598 drawings made after hallucination-inducing SLS at a public installation. Most drawings contained geometric forms, consistent with prior observations, but novel patterns like concentric squares, crosses, and hyperbolic shapes also appeared. The pipeline organized the drawings into interpretable classes, mapping the diversity of simple geometric VHs and placing new constraints on theoretical accounts.
December 13, 2024
Trevor Hewitt, Ioanna Amaya, Romy Beauté et al.
preprint
Exposure to rapid and bright stroboscopic light can induce vivid visual hallucinations of color and geometric forms, a phenomenon first documented by Purkinje over 200 years ago. Despite centuries of scientific, therapeutic, and cultural interest, fundamental questions remain about its phenomenology, physiological origins, and potential clinical applications. This narrative review summarizes the historical research on stroboscopic light stimulation, its use in recreational and lay-therapeutic settings, and discusses the phenomenology of these experiences. It also examines current perspectives on the neural mechanisms that may underlie stroboscopically induced experiences and outlines directions for future research.
medRxiv Preprint Server
June 17, 2026
Danny Nacker, Luise Kalus, Anil K. Seth et al.
preprint
Supervised stroboscopic light stimulation (SLS) was safe, tolerable, and feasible in adults with depressive symptoms, but efficacy was not established. In a staged program, 31 participants tested 11 SLS parameter sets; no severe adverse reactions occurred, and mean discomfort was low (0.49 out of 10). A subsequent randomized trial assigned 84 participants to four weekly 31-minute sessions of SLS or a low-phenomenology control. Retention was 83.3% (70 of 84 participants), with higher retention in the intervention arm (39 of 42) than the control arm (31 of 42). Exploratory depressive-symptom changes suggested a possible signal on the BDI-II but do not confirm efficacy. The next step is a Phase 2a feasibility trial with a locked protocol.
arXiv Preprint Archive
February 25, 2025
Romy Beauté, David J. Schwartzman, Guillaume Dumas et al.
Stroboscopic light stimulation on closed eyes typically induces simple visual hallucinations—vivid, geometric, and colorful patterns. An analysis of 862 open-ended reports from the Dreamachine immersive experience, using large language models and topic modeling, confirmed these simple hallucinations and also revealed altered states of consciousness and complex hallucinations. This computational approach enables systematic study of subjective experiences beyond standard questionnaires, capturing subtle patterns not readily identified through closed-form questions. The findings broaden understanding of stroboscopically induced phenomena and demonstrate the potential of natural language processing in computational neurophenomenology.
Neuroscience of Consciousness
January 1, 2025
Trevor Hewitt, Ioanna Amaya, Romy Beauté et al.
Exposure to rapid, bright stroboscopic light has been known for over 200 years to induce vivid visual hallucinations of color and geometric shapes. This narrative review summarizes the history of research on stroboscopic light stimulation (SLS), its recreational and lay-therapeutic uses, the phenomenology of the experiences it produces, and current understanding of potential neural mechanisms. Despite progress, fundamental questions remain about the full characterization of its phenomenology, its precise physiological origins, the conditions under which it leads to altered states of consciousness, and possible clinical applications.