Although there has been a considerable increase in research on ASMR, experimental studies on the triggers of ASMR induction are scarce. Prior to this research, it had been a common understanding that auditory triggers were more ASMR-inducing than visual triggers 3,10,14 and the capability of visual triggers has been overlooked. Audio-only ASMR-inducing content has been popular, whereas visual-only ASMR-inducing content has been scarce. Furthermore, a working model proposed recently 3 considers that the caudal auditory fields, with their links to both spatial processing and somatosensory processing, may be critical links in the induction of ASMR. In this study, through Experiments 1 and 2, we demonstrated that the enhancement of auditory-induced ASMR by simultaneously presented visual triggers is due to the added information about the source of the auditory triggers. Furthermore, most importantly, it was shown that visual triggers alone were capable of inducing ASMR, although the frequency was less than that of auditory triggers alone. The generalization of these findings is provided by the sufficient number of newly prepared stimuli that successfully induced ASMR within a short duration. Below, we discuss the significance of our findings and future directions using our stimulus set.
The current findings indicate that, counterintuitively, ASMR is not an audio-dependent response. The visually induced ASMR itself does not necessarily deny the audio dependence of ASMR; one possible explanation is that the auditory trigger was compensated for by mental imagery when the presented trigger was visual only. In that case, ASMR was induced by an imaginary auditory trigger. However, this possibility conflicts with the result of ASMR occurrence timing in Experiment 2; that is, the occurrence timing was faster in the visual condition than in the audio condition. If imaginary auditory triggers are necessary for ASMR induction in the visual condition, the occurrence should be slower than that in the audio condition. Therefore, the current results comprehensively indicate the capability of visual triggers to induce ASMR and have significantly contributed to stimulating future research on the mechanisms of visually induced ASMR.
The ASMR-inducing stimuli that succeeded in inducing ASMR by visual trigger only were strongly associated with object properties compared to audio trigger only stimuli. Although most of the stimuli induced ASMR by visual trigger only at least once (45 out of 50), the stimuli that frequently induced ASMR were about object manipulation without person (e.g., cutting a solid soap into pieces, running over and crushing various types of small balls with a car, cutting or pressing a shaped sand). This result empirically extends the finding reported by Barratt et al. 10 that “Focusing on the material the object is made from” is subjectively the second most important factor for triggering ASMR; the visual stimulus of manipulating the objects is not just a supporter of auditory ASMR induction but induces ASMR by itself. Further research is needed to reveal aspects of object properties that are crucial for visual ASMR.
Under the premise that ASMR induced by an auditory trigger and that induced by a visual trigger are regarded as the same, the factors common across these modalities might be crucial for ASMR induction. We propose that the sense of presence, which would be associated with ASMR induction and common across auditory and visual modality 3, might be one of the factors associated with the apparent predominance of auditory triggers over visual triggers. There are tricks in the ASMR-inducing stimuli that help viewers be immersed in the content (e.g., touching the mic or camera, role-playing with first-person viewing). In this context, the auditory sense of presence can be easily experienced by stereophonic sounds with regular audio devices. Conversely, the visual sense of presence is not that easy; experiencing virtual reality, which corresponds to stereophonic sound in auditory modality, requires specific devices that require viewers’ efforts to play. Thus, with respect to experiencing a sense of presence, visual modality without using virtual reality (true for almost all extant ASMR-inducing stimuli) is possibly far less effective than auditory modality. Furthermore, even without virtual reality, the distance between the camera and the object that is manipulated in the ASMR-inducing stimuli reduces the intensity of ASMR 10. Thus, the capability of visual triggers to induce ASMR might be comparable to auditory triggers when investigated in a virtual reality situation.
This study has several limitations that should be considered in future research. First, there is no objective definition of ASMR. We defined the induction of ASMR based on subjective responses, which might have increased undesirable noises such as incorrect responses (i.e., omission and commission errors). However, the lack of an objective definition of ASMR has been a common issue in ASMR research. Although several studies have reported neurophysiological responses that correspond to ASMR 11, 13–15,26–28, no reliable index has been found. This issue should be addressed in future studies. Second, the newly prepared ASMR-inducing stimulus set does not cover every category of popular ASMR content. For example, Mukbang, in which people consume large quantities of food, has been growing as a major category of ASMR content 5. Developing a stimulus set would help future research investigating ASMR-inducing stimuli and a comprehensive understanding of the properties of the triggers.
In conclusion, the current research provides the first empirical evidence that the visual trigger is capable of inducing ASMR alone and that it enhances auditory-induced ASMR by providing information about the source of the auditory trigger. Additionally, we developed a stimulus set that included a sufficient number of stimuli to successfully induce ASMR. This stimulus set enabled us to obtain generalizable results and, along with the current findings, can facilitate psychophysiological research on the properties of ASMR-inducing stimuli.