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Scientific Reports May 2024It has been argued that experiencing the pain of others motivates helping. Here, we investigate the contribution of somatic feelings while witnessing the pain of others...
It has been argued that experiencing the pain of others motivates helping. Here, we investigate the contribution of somatic feelings while witnessing the pain of others onto costly helping decisions, by contrasting the choices and brain activity of participants that report feeling somatic feelings (self-reported mirror-pain synesthetes) against those that do not. Participants in fMRI witnessed a confederate receiving pain stimulations whose intensity they could reduce by donating money. The pain intensity could be inferred either from the facial expressions of the confederate in pain (Face condition) or from the kinematics of the pain-receiving hand (Hand condition). Our results show that self-reported mirror-pain synesthetes increase their donation more steeply, as the intensity of the observed pain increases, and their somatosensory brain activity (SII and the adjacent IPL) was more tightly associated with donation in the Hand condition. For all participants, activation in insula, SII, TPJ, pSTS, amygdala and MCC correlated with the trial by trial donation made in the Face condition, while SI and MTG activation was correlated with the donation in the Hand condition. These results further inform us about the role of somatic feelings while witnessing the pain of others in situations of costly helping.
Topics: Humans; Female; Male; Adult; Magnetic Resonance Imaging; Pain; Young Adult; Brain; Brain Mapping; Facial Expression; Helping Behavior; Hand
PubMed: 38773183
DOI: 10.1038/s41598-024-62422-3 -
Cognition May 2024Absolute pitch is the name given to the rare ability to identify a musical note in an automatic and effortless manner without the need for a reference tone. Those...
Absolute pitch is the name given to the rare ability to identify a musical note in an automatic and effortless manner without the need for a reference tone. Those individuals with absolute pitch can, for example, name the note they hear, identify all of the tones of a given chord, and/or name the pitches of everyday sounds, such as car horns or sirens. Hence, absolute pitch can be seen as providing a rare example of absolute sensory judgment in audition. Surprisingly, however, the intriguing question of whether such an ability presents unique features in the domain of sensory perception, or whether instead similar perceptual skills also exist in other sensory domains, has not been explicitly addressed previously. In this paper, this question is addressed by systematically reviewing research on absolute pitch using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) method. Thereafter, we compare absolute pitch with two rare types of sensory experience, namely synaesthesia and eidetic memory, to understand if and how these phenomena exhibit similar features to absolute pitch. Furthermore, a common absolute perceptual ability that has been often compared to absolute pitch, namely colour perception, is also discussed. Arguments are provided supporting the notion that none of the examined abilities can be considered like absolute pitch. Therefore, we conclude by suggesting that absolute pitch does indeed appear to constitute a unique kind of absolute sensory judgment in humans, and we discuss some open issues and novel directions for future research in absolute pitch.
PubMed: 38761646
DOI: 10.1016/j.cognition.2024.105805 -
History and Philosophy of the Life... Mar 2024This article analyses the evolutionist discourses on the senses that emerged in the late 19th century, when theories on the evolution of species were in full sway....
This article analyses the evolutionist discourses on the senses that emerged in the late 19th century, when theories on the evolution of species were in full sway. Drawing on newspapers, essays and medical literature, this article aims to set face to face the two currents of thought that I have identified regarding sensory evolution: the one that stressed the value of the progressive specialisation of the senses as evidence for human evolution mainly supported by Max Nordau, and the one which regarded the sensory regrouping, exemplified by the phenomenon of synaesthesia, as the true symptom of evolution, strongly supported by Victor Segalen. A close examination of their arguments will provide clues concerning their relative position vis-à-vis the theory that stressed the exceptional nature of humankind among all living beings. Based on newspapers, essays and medical literature, this paper, which straddles several fields (history of science, philosophy, cultural history and aesthetics) aims to set both positions face to face, examining their arguments in detail and establishing their genealogies. This will lead to a better understanding of the scope and range of evolutionist discourses in the fin de siècle culture and on their impact upon artistic practices.
Topics: Humans; Philosophy; Esthetics
PubMed: 38478178
DOI: 10.1007/s40656-024-00615-9 -
Scientific Reports Mar 2024There are many different kinds of 'phantom' percepts but it is unknown whether they are united by common mechanisms. For example, synaesthesia (e.g., numbers evoking...
There are many different kinds of 'phantom' percepts but it is unknown whether they are united by common mechanisms. For example, synaesthesia (e.g., numbers evoking colour) and hallucinations appear conceptually and phenomenologically similar: both result in a percept that does not have an environmental correlate. Here, people with synaesthesia (n = 66) performed a conditioned hallucinations paradigm known to be sensitive to hallucination susceptibility, and we asked whether synaesthetes would show the same behavioural profile as hallucinators in this task. Repeated pairing of checkerboards with tones, and gratings with colours encourages the participant to draw on prior knowledge when asked to report on the presence of the difficult-to-detect target stimulus. Synaesthetes show increased modelled expectancies for the stimulus association across the board, resulting in a higher number of detections at all stimulus intensities. This is in contrast to the pattern observed in hallucinators, who weigh their prior beliefs more strongly than controls, giving rise to more conditioned hallucinations. Results indicate that fundamentally different perceptual processes may be at the core of these seemingly similar experiences.
Topics: Humans; Synesthesia; Perceptual Disorders; Color Perception; Hallucinations; Caffeine
PubMed: 38453946
DOI: 10.1038/s41598-024-53663-3 -
PNAS Nexus Mar 2024Recent artificial intelligence (AI) tools have demonstrated the ability to produce outputs traditionally considered creative. One such system is text-to-image generative...
Recent artificial intelligence (AI) tools have demonstrated the ability to produce outputs traditionally considered creative. One such system is text-to-image generative AI (e.g. Midjourney, Stable Diffusion, DALL-E), which automates humans' artistic execution to generate digital artworks. Utilizing a dataset of over 4 million artworks from more than 50,000 unique users, our research shows that over time, text-to-image AI significantly enhances human creative productivity by 25% and increases the value as measured by the likelihood of receiving a favorite per view by 50%. While peak artwork Content Novelty, defined as focal subject matter and relations, increases over time, average Content Novelty declines, suggesting an expanding but inefficient idea space. Additionally, there is a consistent reduction in both peak and average Visual Novelty, captured by pixel-level stylistic elements. Importantly, AI-assisted artists who can successfully explore more novel ideas, regardless of their prior originality, may produce artworks that their peers evaluate more favorably. Lastly, AI adoption decreased value capture (favorites earned) concentration among adopters. The results suggest that ideation and filtering are likely necessary skills in the text-to-image process, thus giving rise to "generative synesthesia"-the harmonious blending of human exploration and AI exploitation to discover new creative workflows.
PubMed: 38444602
DOI: 10.1093/pnasnexus/pgae052 -
Neuroscience of Consciousness 2024Predictive processing theories state that our subjective experience of reality is shaped by a balance of expectations based on previous knowledge about the world (i.e....
Predictive processing theories state that our subjective experience of reality is shaped by a balance of expectations based on previous knowledge about the world (i.e. priors) and confidence in sensory input from the environment. Divergent experiences (e.g. hallucinations and synaesthesia) are likely to occur when there is an imbalance between one's reliance on priors and sensory input. In a novel theoretical model, inspired by both predictive processing and psychological principles, we propose that predictable divergent experiences are associated with natural or environmentally induced prior/sensory imbalances: inappropriately strong or inflexible (i.e. maladaptive) high-level priors (beliefs) combined with low sensory confidence can result in reality discrimination issues, a characteristic of psychosis; maladaptive low-level priors (sensory expectations) combined with high sensory confidence can result in atypical sensory sensitivities and persistent divergent percepts, a characteristic of synaesthesia. Crucially, we propose that whether different divergent experiences manifest with dominantly sensory (e.g. hallucinations) or nonsensory characteristics (e.g. delusions) depends on mental imagery ability, which is a spectrum from aphantasia (absent or weak imagery) to hyperphantasia (extremely vivid imagery). We theorize that imagery is critically involved in shaping the sensory richness of divergent perceptual experience. In sum, to predict a range of divergent perceptual experiences in both clinical and general populations, three factors must be accounted for: a maladaptive use of priors, individual level of confidence in sensory input, and mental imagery ability. These ideas can be expressed formally using nonparametric regression modeling. We provide evidence for our theory from previous work and deliver predictions for future research.
PubMed: 38348335
DOI: 10.1093/nc/niae006 -
Perception Mar 2024The replication crisis has taught us to expect small-to-medium effects in psychological research. But this is based on effect sizes calculated over single variables....
The replication crisis has taught us to expect small-to-medium effects in psychological research. But this is based on effect sizes calculated over single variables. Mahalanobis , the multivariate equivalent of Cohen's , can enable very large group differences to emerge from a collection of small-to-medium effects (here, reanalysing multivariate datasets from synaesthetes and controls). The use of multivariate effect sizes is not a slight of hand but may instead be a truer reflection of the degree of psychological differences between people that has been largely underappreciated.
Topics: Humans; Cognition; Synesthesia; Color Perception
PubMed: 38055992
DOI: 10.1177/03010066231218911 -
Scientific Data Nov 2023We provide a neuroimaging database consisting of 102 synaesthetic brains using state-of-the-art 3 T MRI protocols from the Human Connectome Project (HCP) which is...
We provide a neuroimaging database consisting of 102 synaesthetic brains using state-of-the-art 3 T MRI protocols from the Human Connectome Project (HCP) which is freely available to researchers. This database consists of structural (T1- and T2-weighted) images together with approximately 24 minutes of resting state data per participant. These protocols are designed to be inter-operable and reproducible so that others can add to the dataset or directly compare it against other normative or special samples. In addition, we provide a 'deep phenotype' of our sample which includes detailed information about each participant's synaesthesia together with associated clinical and cognitive measures. This behavioural dataset, which also includes data from (N = 109) non-synaesthetes, is of importance in its own right and is openly available.
Topics: Humans; Brain; Magnetic Resonance Imaging; Neuroimaging; Synesthesia
PubMed: 37925503
DOI: 10.1038/s41597-023-02664-4 -
Proceedings. Biological Sciences Oct 2023Synaesthesia is a sensory phenomenon where external stimuli, such as sounds or letters, trigger additional sensations (e.g. colours). Synaesthesia aggregates in families...
Synaesthesia is a sensory phenomenon where external stimuli, such as sounds or letters, trigger additional sensations (e.g. colours). Synaesthesia aggregates in families but its heritability is unknown. The phenomenon is more common in people on the autism spectrum compared with the general population and associated with higher autistic traits. Using classical twin design, we assessed the heritability of individual differences in self-reported synaesthesia and the genetic and environmental contributions to their association with autistic traits within a population twin cohort ( = 4262, age = 18 years). We estimated individual differences in synaesthesia to be heritable and influenced by environmental factors not shared between twins. The association between individual differences in synaesthesia and autistic traits was estimated to be predominantly under genetic influence and seemed to be mainly driven by non-social autistic traits (repetitive behaviours, restricted interests and attention to detail). Our study suggests that the link between synaesthesia and autism might reside in shared genetic causes, related to non-social autistic traits such as alterations in perception. Future studies building on these findings may attempt to identify specific groups of genes that influence both autism, synaesthesia and perception.
Topics: Humans; Adolescent; Autistic Disorder; Sensation; Self Report; Autism Spectrum Disorder
PubMed: 37876199
DOI: 10.1098/rspb.2023.1888 -
Cortex; a Journal Devoted To the Study... Nov 2023As first described by Francis Galton, some persons perceive vividly and automatically in their mind's eye the written form of words that they are hearing. This...
As first described by Francis Galton, some persons perceive vividly and automatically in their mind's eye the written form of words that they are hearing. This phenomenon, labeled ticker-tape synesthesia (TTS), is thought to reflect an abnormally strong influence of speech processing in language areas on to orthographic representations in the visual cortex. Considering the relevance of TTS for the study of reading acquisition, we looked for objective behavioral advantages or impairments in 22 synesthetes, as compared to 22 matched control participants. In three auditory tasks relying on orthographic working memory (letters counting, backward spelling, and letter shape decision), we predicted and observed better performance in synesthetes than in controls. In two visual tasks (lexical decision and letter decision) with a concurrent auditory stimulation, we predicted that synesthetes should suffer from a larger interference by irrelevant speech than controls, but eventually found no difference between the groups. Those results, which we discuss in relation to orthographic processing, mental imagery, and working memory, promote TTS from pure subjectivity to an experimentally measurable phenomenon.
Topics: Humans; Synesthesia; Perceptual Disorders; Memory, Short-Term; Acoustic Stimulation; Imagery, Psychotherapy; Color Perception
PubMed: 37832491
DOI: 10.1016/j.cortex.2023.08.011