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Perception 2017Olfaction is often viewed as difficult, yet the empirical evidence suggests a different picture. A closer look shows people around the world differ in their ability to... (Review)
Review
Olfaction is often viewed as difficult, yet the empirical evidence suggests a different picture. A closer look shows people around the world differ in their ability to detect, discriminate, and name odors. This gives rise to the question of what influences our ability to smell. Instead of focusing on olfactory deficiencies, this review presents a positive perspective by focusing on factors that make someone a better smeller. We consider three driving forces in improving olfactory ability: one's biological makeup, one's experience, and the environment. For each factor, we consider aspects proposed to improve odor perception and critically examine the evidence; as well as introducing lesser discussed areas. In terms of biology, there are cases of neurodiversity, such as olfactory synesthesia, that serve to enhance olfactory ability. Our lifetime experience, be it typical development or unique training experience, can also modify the trajectory of olfaction. Finally, our odor environment, in terms of ambient odor or culinary traditions, can influence odor perception too. Rather than highlighting the weaknesses of olfaction, we emphasize routes to harnessing our olfactory potential.
Topics: Cross-Cultural Comparison; Discrimination, Psychological; Environment; Humans; Individuality; Odorants; Olfactory Perception; Perceptual Disorders; Recognition, Psychology; Synesthesia
PubMed: 28103755
DOI: 10.1177/0301006616688224 -
Psychonomic Bulletin & Review Apr 2024Across the millennia, and across a range of disciplines, there has been a widespread desire to connect, or translate between, the senses in a manner that is meaningful,... (Review)
Review
Across the millennia, and across a range of disciplines, there has been a widespread desire to connect, or translate between, the senses in a manner that is meaningful, rather than arbitrary. Early examples were often inspired by the vivid, yet mostly idiosyncratic, crossmodal matches expressed by synaesthetes, often exploited for aesthetic purposes by writers, artists, and composers. A separate approach comes from those academic commentators who have attempted to translate between structurally similar dimensions of perceptual experience (such as pitch and colour). However, neither approach has succeeded in delivering consensually agreed crossmodal matches. As such, an alternative approach to sensory translation is needed. In this narrative historical review, focusing on the translation between audition and vision, we attempt to shed light on the topic by addressing the following three questions: (1) How is the topic of sensory translation related to synaesthesia, multisensory integration, and crossmodal associations? (2) Are there common processing mechanisms across the senses that can help to guarantee the success of sensory translation, or, rather, is mapping among the senses mediated by allegedly universal (e.g., amodal) stimulus dimensions? (3) Is the term 'translation' in the context of cross-sensory mappings used metaphorically or literally? Given the general mechanisms and concepts discussed throughout the review, the answers we come to regarding the nature of audio-visual translation are likely to apply to the translation between other perhaps less-frequently studied modality pairings as well.
Topics: Humans; Visual Perception; Auditory Perception; Synesthesia; History, 20th Century
PubMed: 37803233
DOI: 10.3758/s13423-023-02343-w -
Frontiers in Psychology Oct 2013Synesthesia is a fairly common condition in which individuals experience atypical responses (such as color experiences) in association with certain types of stimuli... (Review)
Review
Synesthesia is a fairly common condition in which individuals experience atypical responses (such as color experiences) in association with certain types of stimuli (such as non-colored letters). Although synesthesia has been described for centuries, only very recently has there been an explosive growth of systematic scientific examinations of this condition. In this article, we review and critically evaluate current methods for both assessing synesthesia and examining its psychological basis, including the "test-retest" procedure, online battery assessments, and behavioral experiments. We highlight the limitations of these methods for understanding the nature of this complex condition and propose potential solutions to address some of these limitations. We also provide a set of markers that aid in distinguishing synesthesia from other closely related psychological phenomena.
PubMed: 24155733
DOI: 10.3389/fpsyg.2013.00763 -
Frontiers in Bioscience (Elite Edition) Mar 2020Previous research into personality and synaesthesia has focused on adult populations and yielded mixed results. One particular challenge has been to distinguish traits...
Previous research into personality and synaesthesia has focused on adult populations and yielded mixed results. One particular challenge has been to distinguish traits associated with synaesthesia, from traits associated with the ways in which synaesthetes were recruited. In the current study we addressed recruitment issues by testing randomly sampled synaesthetes, and we looked particularly at synaesthesia in childhood. Our child synaesthetes were identified by a screening program across 22 primary schools in the South East of England (n = 3387; children aged 6 to 10 years old). This identified two types of synaesthete (grapheme-colour synaesthesia and sequence-personality synaesthesia), and we tested their personalities using both child-report and parent-report measures. We found strong support for synaesthesia being associated with high Openness to Experience, a personality trait linked to intelligence and creativity. Both synaesthesia subtypes showed this feature, supporting previous research in adults (1-3). We additionally found low Extraversion in grapheme-colour synaesthetes and high Conscientiousness in sequence-personality synaesthetes. We discuss our results with reference to earlier recruitment issues, and as to how perceptual differences such as synaesthesia might link to trait-differences in personality.
Topics: Child; England; Female; Humans; Male; Personality; Synesthesia
PubMed: 32114456
DOI: 10.2741/E865 -
Proceedings of the National Academy of... May 2020Synesthesia is a neurologic trait in which specific inducers, such as sounds, automatically elicit additional idiosyncratic percepts, such as color (thus "colored...
Synesthesia is a neurologic trait in which specific inducers, such as sounds, automatically elicit additional idiosyncratic percepts, such as color (thus "colored hearing"). One explanation for this trait-and the one tested here-is that synesthesia results from unusually weak pruning of cortical synaptic hyperconnectivity during early perceptual development. We tested the prediction from this hypothesis that synesthetes would be superior at making discriminations from nonnative categories that are normally weakened by experience-dependent pruning during a critical period early in development-namely, discrimination among nonnative phonemes (Hindi retroflex /d̪a/ and dental /ɖa/), among chimpanzee faces, and among inverted human faces. Like the superiority of 6-mo-old infants over older infants, the synesthetic groups were significantly better than control groups at making all the nonnative discriminations across five samples and three testing sites. The consistent superiority of the synesthetic groups in making discriminations that are normally eliminated during infancy suggests that residual cortical connectivity in synesthesia supports changes in perception that extend beyond the specific synesthetic percepts, consistent with the incomplete pruning hypothesis.
Topics: Adult; Cognition; Face; Female; Humans; Male; Neuroimaging; Pattern Recognition, Visual; Photic Stimulation; Synesthesia
PubMed: 32321833
DOI: 10.1073/pnas.1914668117 -
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... Mar 2023With effort, most literate persons can conjure more or less vague visual mental images of the written form of words they are hearing, an ability afforded by the links...
With effort, most literate persons can conjure more or less vague visual mental images of the written form of words they are hearing, an ability afforded by the links between sounds, meaning, and letters. However, as first reported by Francis Galton, persons with ticker-tape synesthesia (TTS) automatically perceive in their mind's eye accurate and vivid images of the written form of all utterances which they are hearing. We propose that TTS results from an atypical setup of the brain reading system, with an increased top-down influence of phonology on orthography. As a first descriptive step towards a deeper understanding of TTS, we identified 26 persons with TTS. Participants had to answer to a questionnaire aiming to describe the phenomenology of TTS along multiple dimensions, including visual and temporal features, triggering stimuli, voluntary control, interference with language processing, etc. We also assessed the synesthetic percepts elicited experimentally by auditory stimuli such as non-speech sounds, pseudowords, and words with various types of correspondence between sounds and letters. We discuss the potential cerebral substrates of those features, argue that TTS may provide a unique window in the mechanisms of written language processing and acquisition, and propose an agenda for future research.
Topics: Humans; Synesthesia; Speech; Brain; Language; Dyslexia; Color Perception; Perceptual Disorders
PubMed: 36609103
DOI: 10.1016/j.cortex.2022.11.005 -
Cognitive Research: Principles and... Oct 2020The last few years have seen a rapid growth of interest amongst researchers in the crossmodal correspondences. One of the correspondences that has long intrigued artists... (Review)
Review
The last few years have seen a rapid growth of interest amongst researchers in the crossmodal correspondences. One of the correspondences that has long intrigued artists is the putative association between colours and odours. While traditionally conceptualised in terms of synaesthesia, over the last quarter century or so, at least 20 published peer-reviewed articles have assessed the consistent, and non-random, nature of the colours that people intuitively associate with specific (both familiar and unfamiliar) odours in a non-food context. Having demonstrated such consistent mappings amongst the general (i.e. non-synaesthetic) population, researchers have now started to investigate whether they are shared cross-culturally, and to document their developmental acquisition. Over the years, several different explanations have been put forward by researchers for the existence of crossmodal correspondences, including the statistical, semantic, structural, and emotional-mediation accounts. While several of these approaches would appear to have some explanatory validity as far as the odour-colour correspondences are concerned, contemporary researchers have focussed on learned associations as the dominant explanatory framework. The nature of the colour-odour associations that have been reported to date appear to depend on the familiarity of the odour and the ease of source naming, and hence the kind of association/representation that is accessed. While the bidirectionality of odour-colour correspondences has not yet been rigorously assessed, many designers are nevertheless already starting to build on odour-colour crossmodal correspondences in their packaging/labelling/branding work.
Topics: Art; Association; Color Perception; Environment Design; Humans; Olfactory Perception; Science; Synesthesia
PubMed: 33113051
DOI: 10.1186/s41235-020-00246-1 -
Frontiers in Psychology 2014
PubMed: 25566110
DOI: 10.3389/fpsyg.2014.01414 -
European Neurology 2007Synaesthesia is the intriguing, involuntary experience of feeling one sensation in response to a different sensory stimulus. Recognised since described in 1890 by John... (Review)
Review
Synaesthesia is the intriguing, involuntary experience of feeling one sensation in response to a different sensory stimulus. Recognised since described in 1890 by John Locke and clarified by Galton in the 1880s, it has been analysed in the last 50 years. Grapheme-colour synaesthesia is the commonest form, but many other sensory linkages are reported. Experiments show that it is a genuine immediate perception, not merely a memory or learned association. Many of the mechanisms posited are based on indirect methods, and we know little of the neurophysiological mechanisms.
Topics: Brain; History, 15th Century; History, 19th Century; Humans; Perception; Sensation Disorders
PubMed: 17179720
DOI: 10.1159/000098101