Semantic activation in LSD: evidence from picture naming
This single-blind placebo-controlled study (n=10) investigated the effects of LSD (40-80μg) on lexical retrieval in a picture-naming task and found an increase in the rate at which subjects substituted items with similar words within the same semantic category. These results are consistent with the notion that LSD increases the spread of activation within semantic networks.
Authors
- Robin Carhart-Harris
- David Nutt
- Mendel Kaelen
Published
Abstract
Introduction
Lysergic acid diethylamide (LSD) is a classic psychedelic drug that alters cognition in a characteristic way. It has been suggested that psychedelics expand the breadth of cognition via actions on the central nervous system. Previous work has shown changes in semantic processing under psilocybin (a related psychedelic to LSD) that are consistent with an increased spread of semantic activation.
Methods
The present study investigates this further using a picture-naming task and the psychedelic, LSD. Ten participants completed the task under placebo and LSD.
Results
revealed significant effects of LSD on accuracy and error correction that were consistent with an increased spread of semantic activation under LSD.
Discussion
These results are consistent with a generalised “entropic” effect on the mind. We suggest incorporating direct neuroimaging measures in future studies, and to employ more naturalistic measures of semantic processing that may enhance ecological validity.
Research Summary of 'Semantic activation in LSD: evidence from picture naming'
Introduction
Family and colleagues situate their study within literature showing that serotonergic psychedelics alter cognition and may broaden associative or semantic activation. Previous pharmacological work has demonstrated that manipulating neurotransmitter systems influences language processing: dopaminergic enhancement can narrow semantic activation while prior work with psilocybin suggested an increased spread of semantic activation and greater indirect semantic priming. These observations, together with the "entropic brain" hypothesis that psychedelics increase the unpredictability and breadth of mental associations, motivate further investigation of how LSD affects lexical retrieval. The present study tested whether LSD modulates semantic activation using a picture naming paradigm. Specifically, the investigators hypothesised that LSD would slow naming and increase errors, particularly producing more semantically related lexical substitution errors, consistent with a broader spread of activation in the semantic network. The task design also allowed examination of graded semantic context effects (same, near, far categories), with the aim of determining whether LSD would make near-category items behave more like same-category items by increasing cross-category activation. This was a small pilot, within-subjects comparison of placebo and LSD conditions conducted to inform later neuroimaging work.
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Study Details
- Study Typeindividual
- Journal
- Compound
- Topic
- Authors
- APA Citation
Family, N., Vinson, D., Vigliocco, G., Kaelen, M., Bolstridge, M., Nutt, D. J., & Carhart-Harris, R. L. (2016). Semantic activation in LSD: evidence from picture naming. Language, Cognition and Neuroscience, 31(10), 1320-1327. https://doi.org/10.1080/23273798.2016.1217030
References (9)
Papers cited by this study that are also in Blossom
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Spriggs, M. J., Murphy-Beiner, A., Murphy, R. et al. · Psychological Medicine (2022)
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