Synesthesia: an introduction

Acoustic features of instrumental movie soundtracks elicit distinct and mostly non-overlapping extra-musical meanings in the mind of the listener

Music can evoke powerful emotions in listeners. However, the role that instrumental music (music without any vocal part) plays in conveying extra-musical meaning, above and beyond emotions, is still a debated question. We conducted a study wherein participants (N = 121) listened to twenty 15-second-long excerpts of polyphonic instrumental soundtrack music and reported (i) perceived emotions (e.g., happiness, sadness) as well as (ii) movie scene properties imagined during listening (e.g., scene brightness, character role). We systematically investigated how acoustic features of instrumental soundtrack excerpts (e.g., tempo, loudness) contributed to mental imagery of movie scenes. We show distinct and mostly non-overlapping contributions of acoustic features to the imagination of properties of movie scene settings, characters, actions, and objects. Moreover, we find that negatively-valenced emotions fully mediate the relation between a subset of acoustic features and movie scene properties, providing evidence for the importance of emotional valence in evoking mental imagery. The data demonstrate the capacity of music to convey extra-musical semantic information through audition.

Grapheme-Color Synesthesia and Its Connection to Memory

Synesthesia is the involuntary association of different senses, where individuals experience one sensory modality in response to the stimulation of another. For example, a synesthete may perceive colors when reading certain numbers or associate specific tastes with particular words. Synesthesia manifests differently for individuals grouping the condition in subcategories such as grapheme-color, sound-to-color, lexical-gustatory, mirror-touch, and much more. This review covers grapheme-color synesthesia, described as the involuntary perception of specific colors or color associations when seeing or thinking about certain letters, numbers, or symbols. This review explores the performance of declarative memory tasks in individuals with grapheme-color synesthesia. A comprehensive search of controlled trials published between 2014 to 2024 was conducted through PubMed and Google Scholar databases. In Google Scholar, the search terms grapheme-color synesthesia, grapheme-color synaesthesia, and memory were used. In PubMed, additional MeSH (Medical Subject Headings) terms were used which included grapheme-color synesthesia and memory. Studies that measured declarative memory and grapheme-color synesthesia were included yielding a total of seven controlled trials. Grapheme-color synesthetes demonstrated advanced performance in declarative memory tasks; however, this may not have any clinical significance. Grapheme-color synesthetes demonstrated a better performance in their ability to recall colors, but not as much recalling words. Synesthetes were shown to outperform non-synesthetes in visual memory tasks. Synesthetes showed better recall of paired patterns, shape-color associations, and visual grids compared to control groups, but the influence of synesthesia on word memory remains unclear. Future research should consider adding control for confounding factors, collaborating with other institutions, and increasing sample size.

Autonomous Sensory Meridian Response (ASMR): a flow-like mental state

Autonomous Sensory Meridian Response (ASMR) is a previously unstudied sensory phenomenon, in which individuals experience a tingling, static-like sensation across the scalp, back of the neck and at times further areas in response to specific triggering audio and visual stimuli. This sensation is widely reported to be accompanied by feelings of relaxation and well-being. The current study identifies several common triggers used to achieve ASMR, including whispering, personal attention, crisp sounds and slow movements. Data obtained also illustrates temporary improvements in symptoms of depression and chronic pain in those who engage in ASMR. A high prevalence of synaesthesia (5.9%) within the sample suggests a possible link between ASMR and synaesthesia, similar to that of misophonia. Links between number of effective triggers and heightened flow state suggest that flow may be necessary to achieve sensations associated with ASMR.