Article Summaries
Autonomous Sensory Meridian Response (ASMR) and the Functions of Consciousness
“Autonomous Sensory Meridian Response” (ASMR) is a sensory-emotional experience defined primarily by a distinct tingling sensation in the scalp and upper body, accompanied by feelings of calmness and relaxation. The phenomenon, initially identified in online discussion forums, is argued to be a strong candidate for a real kind in the cognitive sciences due to mounting empirical evidence supporting its robust causal profile and potential adaptive evolutionary history. ASMR is reliably triggered by specific stimuli, many of which are socially relevant, such as whispering, close personal attention, gentle tapping, and viewing simulated intimate social acts. The experience is functionally significant because it acts as a unique strategy for emotional regulation, consistently helping users alleviate symptoms of anxiety, depression, and insomnia. Its neurological profile suggests that it is characterized by a lack of inhibition of sensory-emotional responses (lower functional connectivity in the Default Mode Network and prefrontal regions). The evolutionary function of ASMR may be rooted in a vestigial grooming response observed in primate ancestors, serving to encourage affiliation and relaxation. The study of ASMR is also used to explore the functions of consciousness, particularly arguing that some phenomenal content (the tingling sensation) exists outside the scope of attention.
The multisensory mind: a systematic review of multisensory integration processing in Anorexia and Bulimia Nervosa
This systematic review investigated whether impairments in Multisensory Integration (MSI) contribute to the altered body experience seen in individuals with Anorexia Nervosa (AN) and Bulimia Nervosa (BN). MSI is the crucial process where information from different sensory modalities (exteroceptive, interoceptive) and spatial frames (egocentric/first-person, allocentric/third-person) is combined to create a coherent bodily percept. The review found consistent evidence of MSI abnormalities in patients with AN. Specifically, AN patients exhibited a highly malleable bodily self, reporting significantly higher embodiment levels during the Rubber Hand Illusion (RHI) compared to controls. Deficits appear particularly when combining internal body signals (proprioceptive, vestibular) with external information (visual). The findings support the hypothesis that misperception symptoms reflect a deeper MSI deficit rather than a single sensory modality malfunction. The findings are framed within the Predictive Coding (PP) framework, suggesting that AN involves assigning abnormal precision (weight) to rigid, maladaptive prior beliefs (top-down) over incoming sensory data (likelihood), leading to altered body experience and a failure to update internal models—a tendency called “prior blinding”. Data regarding BN were too limited to draw definitive conclusions.
Important
- ASMR Elicitors – Watching individuals interact with objects, watching individuals perform a socially intimate act, repetitive sounds, viewing simulated social interactions, and hearing whispering or chewing sounds.
- ASMR Mechanism – Arises from a reduced ability to inhibit emotional and sensory experiences. This is supported by convergent evidence showing reduced Default Mode Network (DMN) functional connectivity (which normally filters sensory stimuli), decreased functional connectivity in prefrontal regions (which are responsible for inhibition), and reduced thalamic functional connectivity (indicating reduced ability of the thalamus to filter sensory stimuli before cortical processing).
Core concepts
- Multisensory Processing – The combination of inputs from two or more senses (e.g., visual, tactile, auditory) to enhance each other, resulting in a single, coherent percept.
- Cross-modal Associations (CMA) – Population-level phenomena where associations between sensory features (like louder sounds with bigger objects, or higher pitch with smaller objects) are common. These associations are systematic regularities picked up by the brain from the environment, often related to statistical learning or magnitude matching.
- Synesthesia – An uncommon, intense experience where stimulation in one sensory modality (inducer) automatically and involuntarily causes a concurrent experience in another modality.
- CMA vs. Synesthesia Debate – Revolves around the question of whether cross-modal associations are simply a weaker version of synesthesia or if they are completely different multisensory phenomena.
- Similarities include similarities in the matrix (e.g., A being red, B being blue, C being yellow in general population/synesthetes) and similarities in behavioral effects (like interference in speeded discrimination tasks).
- Differences include explainability (CMAs are generally explainable, synesthetic associations are often idiosyncratic), predictability (CMAs are regular/universal, synesthetic mappings are individual), frequency (CMAs are population-level, synesthesia is rare), transitivity (CMAs are often bidirectional, synesthesia is often unidirectional, though challenged by some studies), and consciousness (synesthesia is a conscious, automatic experience, unlike CMAs which are usually subconscious).
- Ordinal Linguistic Personification (OLP) – The involuntary and automatic tendency to attribute personality and gender to sequential linguistic units like letters, numerals, days, or months.
- ASMR (Autonomous Sensory Meridian Response) – A sensory-emotional experience characterized by a distinct tingling sensation in the scalp and upper body, accompanied by calmness and relaxation, typically triggered by specific sounds or social interactions.
- Proprioceptive Drift – An implicit behavioral measure of the strength of a body illusion (like the RHI), specifically defined as the change in the perceived location of the real, unseen hand toward the fake hand.
- The Perception Census – A project started by Anil Seth and colleagues in 2022 to identify and appreciate the diversity of sensory experiences globally, gathering data on cross-modal associations, illusions, and unique experiences from thousands of participants. The project has revealed that experiences once considered rare, such as the strength of certain visual illusions or out-of-body experiences, show high variability in the population.
Theories and Frameworks
- Neonatal Synesthesia Hypothesis – Proposes that cross-modal associations and synesthesia both originate from hyperconnectivity between sensory cortices in infancy, where synesthesia is the particularly intense result of incomplete pruning.
- Cross-activation Theory of Synesthesia – An extension of the neonatal hypothesis that incorporates genetics of pruning and hyper-binding in association cortices, proposing that synesthesia arises due to increased connectivity between cortical regions that process the inducing and concurrent features. This model is supported by evidence in grapheme-color synesthesia, where adjacent areas processing color and graphemes show recurrent loops.
- Predictive Coding (PP) Framework – Views the brain as a “Bayesian prediction machine” where percepts are constructed by comparing incoming sensory information (likelihood) with internal representations (priors) to minimize the prediction error (PE). This framework is used to explain multisensory integration abnormalities in Eating Disorders, suggesting that patients rely too heavily on prior beliefs (prior blinding).
- Allocentric Lock Theory (ALT) – Suggests that Eating Disorders (EDs) are characterized by deficits in integrating allocentric (stored, memory-based somatic information) and egocentric (incoming sensory information) perspectives of the body, potentially leading to a persistent, false representation of the body that cannot be easily updated.
Notable Individuals
- Anil Seth: Neuroscientist and cognitive scientist who initiated the Perception Census project to catalog and appreciate the diversity of sensory experiences.
- Downs and Black: Developed the checklist used for assessing the methodological quality and risk of bias in comparative health care intervention studies.
- Virginia Woolf: Author whose novel Mrs. Dalloway (1925) contains a passage that some writers point to as potentially describing the ASMR phenomenon before it was formally labeled.
- Julia Simner & Emma Holenstein: Authors who argued that Ordinal Linguistic Personification (OLP) should be considered a variant of synesthesia.