ASMR is a complex sensory-emotional experience characterized by relaxing tingling sensations originating in the scalp. It is a feeling elicited in some people by stimuli including whispering, soft touch, personal attention, crisp sounds, and slow hand movements. Since the term ‘ASMR’ was coined, it has attracted attention from psychological science. ASMR has been likened to synesthesia, with parallels between the two inferred by their similar phenomenology and neurocognitive profiles. However, empirical evidence directly linking ASMR with synesthesia is sparse and appears to show only a weak link between ASMR and some types of synesthesia 2,26. In this study, we examined, for the first time, whether the prevalence of synesthesia is indeed significantly higher in ASMR-responders compared to non-responders. Such an association would provide empirical support for theoretical accounts of ASMR that are based on mechanisms thought to underlie synesthesia 8.
In the present study, a large sample of working adults and students (N = 648) was surveyed about their experience with ASMR and common types of synesthesia. Of the whole sample, 9% reported at least one type of synesthetic mapping and 23% were classified as ASMR-responders. An additional 14% watched ASMR content online, but did not report feeling the canonical ASMR-tingling, and were therefore classified as non-responders. At 9%, our overall prevalence rate of synesthesia is comparable, but typically lower than rates observed in studies using similar methodology, where self-reporting is sufficient for inclusion, e.g., 19% for Chun & Hupé, 2013, 9–17% for Rouw & Erfanian, 2018, 24% for Rouw & Scholte, 2016, 16–23% for Barnett et al., 2008). After removing ASMR-responders, synesthesia prevalence was 5%, a rate more consistent with studies using more stringent inclusion criteria 25.
To our knowledge, there are no previously reported prevalence rates for ASMR. However, one study, which did not use additional verification methods for ASMR-responder classification as was done here, suggested a 47% prevalence rate in a student sample 29. Based on the current findings we would tentatively suggest a prevalence rate for ASMR of approximately 20%, i.e., around one in five people experience ASMR. This would, of course, need to be verified with appropriate methodology, ideally with random sampling across demographics, and with additional verification measures for ASMR responses 30 and consistency 31.
Our central research question concerned the co-occurrence of ASMR and synesthesia – is synesthesia more common among ASMR-responders, and is ASMR more common among synesthetes? The answer to both, it would seem, is yes. In our sample, 52% of synesthetes were classified as ASMR-responders. The proportion of ASMR-responders who were also synesthetes was 22%. Taken together, these results suggest that: (1) over half of those identifying as synesthetes also experience ASMR, and (2) that synesthesia is at least twice as common in ASMR-responders as in non-responders who watch ASMR content (22% vs. 11%) and four times as common as among those who do not watch ASMR content at all (22% vs. 5%).
The rate of synesthesia among our ASMR-responders (22%) was nearly four times higher than reported in Barratt and Davis (2015), who reported a 5.9% incidence of synesthesia in ASMR. Twenty-eight of their 33 cases were deemed genuine after asking for descriptions of inducer-concurrent mappings (see their supplementary materials) and comprised more mappings than we asked about in the present investigation, e.g., music-form, sound-taste. One possibility for the discrepancy between studies in synesthesia prevalence in ASMR is the method of assessment, which may have led to an underestimation of synesthesia in the former study and an overestimation of synesthesia in the current study.
Barratt and Davis (2015) assessed synesthesia by providing a description (“perception in one sense triggering sensation in another, unstimulated sense. For example, you may ‘see’ the letters as having colors, or sense shapes from music”) and asked participants to report whether they had any type of synesthesia with a single question (“Do you have any type of synesthesia?”). In our study however, we made no mention of synesthesia, and instead asked a series of questions intended to tap specific inducer-concurrent mappings, e.g., “Do you associate letters or numbers with specific colors?”. One possible explanation is that due to the method used, many more ASMR-responders in the Barratt & Davis (2015) study did experience synesthetic-type mappings, but did not report having synesthesia due to unfamiliarity with the term and/or unawareness that their cross-modal correspondences are in any sense remarkable. Similarly, our method may have overestimated the prevalence of genuine cases of synesthesia because we did not explicitly examine the consistency or specificity of cross-modal correspondences reported against hallmarks considered necessary for canonical synesthesia 32. Our results should therefore be considered with caution and followed up by more extensive testing to determine the veracity of self-reported synesthesia (ideally consistency tests) against predefined ‘diagnostic’ criteria 33.
Irrespective of the limitation of assessing synesthesia through self-reporting, a substantial strength of our study was the inclusion of a non-ASMR sample, because it enabled a direct comparison of synesthesia rates in ASMR-responders and non-responders. Such an ‘uncontaminated’ comparison population is not possible when comparing against existing synesthesia population rates, which include ASMR participants. An additional strength of our method was the use of verification procedures for classifying ASMR-responders, rather than simply relying on self-disclosure. We used experience of ASMR content online as a useful heuristic for initially identifying ASMR-responder status. Of the 243 participants who had watched ASMR content, only 63% were classified as ASMR-responders by reporting the presence and anatomical location of ASMR-tingling. This classification was further supported by an examination of ‘flow-to-ASMR’ scale responses that were substantially higher among our verified ASMR-responders compared to those who watch ASMR content, but do not experience ASMR-tingling. Although it is still a matter of debate whether tingling sensations and location (focused in the upper body) are necessary conditions for trait or state ASMR, recent work suggests that these features distinguish both ASMR-responders from non-responders, and ASMR-responders from false-positives 30.
The ability to screen out participants who may engage with ASMR content in the absence of ASMR sensations is vital, given the increasing popularity of ASMR and the widespread use of ASMR triggers/style in popular culture and media 34. We wish to point out that ‘ASMR content’ is often used synonymously with ‘ASMR’ as a specific sensation/emotional experience, but the two should not be conflated. Watching ASMR or being familiar with the term does not mean that an individual experiences ASMR as a sensation. Greater awareness of ASMR as a term increases the need for more rigorous identification of genuine cases of ASMR, rather than those that simply recognize the term, have seen ASMR content, or have a strong emotional response to ASMR content/triggers that would not be considered state ASMR, i.e., pleasant, calming, upper body orientated tingling in response to specific triggers, but might more closely resemble other experiences such as frisson or misophonia 35,36. Similarly, not engaging with ASMR content or not being aware of the term, despite its popularity, does not preclude an individual from experiencing the sensation and being a genuine ASMR-responder. This means that in our study, by first asking participants to indicate their experience with ASMR content online, we may have inadvertently miscategorized genuine ASMR-responders as non-responders. Therefore, it is possible that we have underestimated the prevalence of ASMR-responders in our sample and also, by extension, the number of ASMR-responders with synesthetic mappings.
What might explain the co-occurrence of ASMR and synesthesia? One possibility we discussed in the Introduction is that they share a common genetic and or neurocognitive basis. Support for this idea comes from studies that show heightened sensory sensitivity in both ASMR 9 and synesthesia 37, altered patterns of neural connectivity 13,17,18, developmental origins 6,7, and a shared broader phenotype 10,12. Another possibility that may explain their co-occurrence is that people with ASMR and synesthesia are both simply more likely to report anomalous experiences. Although this should be tested more directly, recent research suggests that ASMR-responders are not more likely to self-report unusual sensory experiences compared to a control group 38. A third possibility is that ASMR is itself an as yet unclassified form of synesthesia that should be added to existing typologies. Although this is a tempting possibility, we would like to conclude by highlighting the ways in which ASMR and synesthesia are different.
First, ASMR inducer-concurrent pairings are less idiosyncratic. Although ASMR-responders show subtle differences in ASMR trigger preferences, studies demonstrate consistency in the ASMR triggers endorsed, e.g., whispering, soft touch, close personal attention, and in the described concurrent location of tingling 6,30. Thus, the stimuli that induce ASMR are remarkably similar among responders, unlike synesthesia, in which inducer-concurrent pairings appear to be highly specific to individuals 39.
Second, rather than traditional one-to-one inducer concurrent mappings specific to each synesthete 40, ASMR responders typically have what we might call a many-to-one inducer-concurrent mapping. Many triggers/inducers induce the same concurrent among responders, with the experience of ASMR often occurring with greater intensity when triggers from multiple senses are integrated. In this way, the ASMR inducer is not typically unimodal 31.
Third, at least for some ASMR triggers, the relationship between inducer and concurrent is not arbitrary. Associating close personal attention, soft touch, slow movements or whispering with feelings of relaxation and pleasant tingling appears to mirror typical experiences of intimacy in close personal relationships 41. This stands in contrast to synesthetic mappings, which appear to have an arbitrary association that is not immediately explainable (Deroy & Spence, 2013).
Fourth, whereas synesthetic associations are often considered involuntary or automatic responses 5,42, ASMR appears to be more affected by contextual factors, e.g., eating sounds may trigger ASMR in one context, but misophonia in another and susceptible to habitation (termed ASMR immunity). Taken together, these differences suggest that ASMR differs from synesthesia in a number of important and interesting ways. We tentatively suggest that ASMR may best be considered a heightened or exaggerated cross-modal correspondence related to hedonic touch 43, rather than a subtype of synesthesia. Nevertheless, future research would benefit from exploring features that differentiate ASMR from synesthesia, and not only their similarities.