Lexical–gustatory synesthesia: Difference between revisions
m Added in links to other Wikipedia articles |
Edited Case Studies Section. Added information on JIW and PS. Edited section headers to Case Studies Section. Edited the wording of the experimental studies section. Edited experiences and phonological roots with references included. |
||
| Line 1: | Line 1: | ||
'''Lexical-gustatory synesthesia''' is a rare form of [[Synaesthesia|synesthesia]] |
'''Lexical-gustatory synesthesia''' is a rare form of [[Synaesthesia|synesthesia]] in which both spoken and written language causes individuals to experience an automatic and highly consistent associated taste.<ref name=Simner/Ward>{{cite journal|last=Simner|first=Julia|coauthors=Ward|title=The taste of words on the tip of the tounge|journal=Nature|date=23|year=2006|month=November|volume=444|page=438|doi=10.1038/444438a}}</ref> The taste is often experienced as a complex mixture of both temperature and texture. For example, in a particular synaesthete JIW, the word jail would taste of cold, hard bacon.<ref name=SimnerReview>{{cite journal|last=Simner|first=Julia|title=Beyond perception: synaesthesia as a psycholinguistic phenomenon|journal=TRENDS in Cognitive Sciences|date=29|year=2006|month=November|volume=11|issue=1|pages=23-29|doi=10.1016/j.tics.2006.10.010|}}</ref><ref name=Colizoli>{{cite journal|last=Colizoli|first=Olympia|coauthors=J. Murre, R. Rouw|title=A taste for words and sounds: a case of lexical-gustatory and sound-gustatory synesthesia|journal=Frontiers in Psychology|date=23|year=2013|month=October|volume=4|issue=775|doi=10.3389/fpsyg.2013.00775|pmid=PMC3806228|url=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3806228/}}</ref> Synesthetic tastes are evoked by an inducer/concurrent complex. The inducer is the stimulus that activates the sensation and the taste experience is the concurrent.<ref name=Logie>{{cite journal|last=Simner|first=Julia|coauthors=R. Logie|title=Synaesthetic Consistency Spans Decades in a Lexical-Gustatory Synaesthete|journal=Neurocase|year=2007|volume=13|pages=358-365|doi=10.1080/13554790701851502}}</ref> |
||
==Experiences== |
|||
* PS is a patient that has taste experiences that happen in her head and not her mouth<ref name=Richer>{{cite journal|last=Richer|first=Francois|coauthors=G. Beaufils, S. Poirer|title=Bidirectional lexical-gustatory synesthesia|journal=Consciousness and Cognition|date=4|year=2011|month=February|volume=20|pages=1738-1743|doi=10.1016/j.concog.2010.12.015}}</ref> |
|||
* Taste usually has both texture and temperature associated with the sensation<ref name=SimnerReview /> |
|||
==Experimental Studies== |
==Experimental Studies== |
||
There |
There are many scientific standards in use to determine if a person actually has the genuine neurological condition of lexical-gustatory synesthesia. Scientists check for the behavioral hallmark of a significantly higher retest consistency after at least a year compared to control groups. Another scientific standard method to determine the legitimacy of ones synesthesia is to use [[Functional magnetic resonance imaging|Functional magnetic resonance imaging or functional MRI]] (fMRI) to determine which areas of the brain are active during the scan. |
||
<ref name=Simner/Ward /><ref name=SimnerReview /><ref name=Haywood>{{cite journal|last=Simner|first=Julia|coauthors=Sarah L. Haywood|title=Tasty non-words and neighbors: The cognitive roots of lexical-gustatory synaesthesia|journal=Cognition|year=2011|volume=110|pages=171-181|doi=10.1016 b/j.cognition.2008.11.008}}</ref> A final method |
<ref name=Simner/Ward /><ref name=SimnerReview /><ref name=Haywood>{{cite journal|last=Simner|first=Julia|coauthors=Sarah L. Haywood|title=Tasty non-words and neighbors: The cognitive roots of lexical-gustatory synaesthesia|journal=Cognition|year=2011|volume=110|pages=171-181|doi=10.1016 b/j.cognition.2008.11.008}}</ref> A final method utilized by the prominent neuroscientist, V.S. Ramachandran, is the [[Galvanic Skin Response|galvanic skin response]] (GSR). The GSR measures any fluctuations in the electrical resistance of skin. A high GSR could indicate that a person my be lying about their synesthesia condition. No GSR indicates that a person would be telling the truth about their synesthesia. |
||
<ref name=Ramachandran>{{cite book|last=Ramachandran|first=V.S.|title=The Tell-Tale Brain: A Neuroscientist's Quest for What Makes Us Human|year=2011|publisher=W.W.Norton & Company, Inc.|location=New York, NY|isbn=978-0-393-07782-7|pages=75-116}}</ref> |
<ref name=Ramachandran>{{cite book|last=Ramachandran|first=V.S.|title=The Tell-Tale Brain: A Neuroscientist's Quest for What Makes Us Human|year=2011|publisher=W.W.Norton & Company, Inc.|location=New York, NY|isbn=978-0-393-07782-7|pages=75-116}}</ref> |
||
===Phonological Roots=== |
===Experiences and Phonological Roots=== |
||
There are many forms of lexical-gustatory synesthesia and the various taste sensations linked to the neurological condition vary widely from synesthete to synesthete.<ref name=Bankieris>{{cite journal|last=Bankieris|first=Kaitlyn|coauthors=J. Simner|title=Sound symbolism in synesthesia: Evidence from a lexical-gustatory synesthete.|journal=Neurocase: The Neural Basis of Cognition|year=2013|doi=10.1080/13554794.2013.826693|pmid=23972101|url=http://www.ncbi.nlm.nih.gov/pubmed/23972101}}</ref> Examples of many well known synesthetic taste experiences are recorded in case studies with singular participants that demonstrate the variability of the condition. In one case, PS is a patient that has taste experiences that happen in her head and not her mouth.<ref name=Richer>{{cite journal|last=Richer|first=Francois|coauthors=G. Beaufils, S. Poirer|title=Bidirectional lexical-gustatory synesthesia|journal=Consciousness and Cognition|date=4|year=2011|month=February|volume=20|pages=1738-1743|doi=10.1016/j.concog.2010.12.015}}</ref> Her tastes usually have both texture and temperature associated with the sensation.<ref name=SimnerReview />Some forms of lexical-gustatory synesthesia are triggered by thinking of the word's meaning, rather than its sound or spelling. Others are triggered by hearing or reading an inducer word.<ref name=Simner/Ward /> In many forms, more well known words and words used with a higher frequency are more likely to have a strong taste association <ref name=SimnerReview /> <ref name=Bankieris /> The phonological roots associated with this form of synesthesia drive the current research on lexical-gustatory synesthesia to determine which parts of the brain are active in synesthetes causing the neurological cross-talk condition and how the findings may relate to neurologically normal persons.<ref name=SimnerReview /> <ref name=Colizoli /> |
|||
* Lexical-gustatory synesthesia is triggered by thinking of the word's meaning, rather than its sound or spelling<ref name=Simner/Ward /> |
|||
* Hearing or reading the word also triggers<ref name=Simner/Ward /> |
|||
* More well known words/higer frequency words are more likely to have a strong taste association<ref name=SimnerReview /> |
|||
===Tip of the tongue studies=== |
===Tip of the tongue studies=== |
||
| Line 19: | Line 13: | ||
===Case Studies=== |
===Case Studies=== |
||
====JIW==== |
|||
* JIW<ref name=SimnerReview /><ref name=Logie /> |
|||
JIW is a synesthete who automatically experiences tastes in and around his mouth when he hears words. He describes his tastes to be very similar to real tastes experienced when eating, but without the substance. JIW’s case study to evaluate the consistency in a series of re-tests began in the late 1970s. In 2006, exactly 27 years after his initial study, JIW and a group of ten controls who were not a part of the original study were re-tested using words from original 1970s study. The controls were instructed that they would be immediately retested on their inducer-concurrent associations. The results of the 2006 study indicated that the controls had a mean consistency of about 47.9% while JIW had maintained a consistency of 100%.<ref name=SimnerReview /><ref name=Logie /> |
|||
* PS<ref name=Richer /> |
|||
JIW’s tastes are largely correlated to foods that he would have eaten as a child. He is around ten times more likely to associate a word to the taste of chocolate than he would to the taste of something he experienced as an adult, such as a beer or coffee. For example, when JIW hears a common word such as this, he experiences the tastes of ‘bread soaked in tomato soup’. Bread and tomato soup would have been common flavors JIW experienced in his childhood. It is hypothesized that some or all forms of lexical-gustatory synesthesia may trigger during early childhood development and lead to the over-representation of the flavors of childhood foods.<ref name=SimnerReview /><ref name=Logie /> |
|||
Both consistency studies and fMRI scans have validated JIW’s lexical-gustatory synesthesia. A fMRI scan showed the bilateral activation of the [[gustatory cortex|Broca’s area 43]] in the brain during JIW’s taste experiences. The Broca’s area 43 is a part of the primary gustatory cortex which is responsible for the perception of taste. Further studies of the underlying brain regions involved in synesthetes like JIW could aid in identifying the root physiological mechanisms involved in lexical-gustatory synesthesia.<ref name=SimnerReview /><ref name=Logie /> |
|||
====SC==== |
|||
SC is a synesthete who automatically experiences smells, tastes, and feelings of textures in her mouth and throat when she reads, speaks, or hears language, music, and certain environmental sounds. In SC’s case study, researchers utilized [[Functional magnetic resonance imaging|fMRI]] to determine the areas of the brain that were activated during her synesthetic experiences. They compared areas of activation in SC’s brain to those found in literature for other synesthetes, speech processing, language, and sound processing. In SC’s scans, two important regions of the brain were largely activated during her taste sensations: the [[insular cortex|left anterior insula]] and the [[parietal lobe|left superior parietal lobe]]. The scans led researchers to speculate that the anterior insula may play a role in SC’s taste experiences while the superior parietal lobe binds together all of the sensory information for processing. Based off the findings of this study and others like it, it could be possible to determine the type of inducer that leads to synesthetic sensations based on the patterns of brain activity.<ref name=Colizoli /> |
|||
==Possible Neural Basis== |
==Possible Neural Basis== |
||
| Line 26: | Line 27: | ||
==Possible Genetic Basis== |
==Possible Genetic Basis== |
||
Approximately 2%-4% of the population has some form of synesthesia. An even smaller percentage, around 0.2% or lower, have lexical-gustatory synesthesia. There appears to be a strongly linked genetic component to neurological cross-linking phenomenon.<ref name=Haywood /> <ref name=Brang>{{cite journal|last=Brang|first=David|coauthors=V.S. Ramachandran|title=Survival of the Synesthesia Gene: Why Do People Hear Colors and Taste Words?|journal=PLoS Biology|year=2011|month=November|volume=9|issue=11|doi=10.1371/journal.pbio.1001205|url=http://cogns.northwestern.edu/dbrang/images/Brang_PlosBiology_2011.pdf}}</ref> Lexical-gustatory synesthesia and other forms of synesthesia are familial, meaning that they are passed on through a family<ref name= |
Approximately 2%-4% of the population has some form of synesthesia. An even smaller percentage, around 0.2% or lower, have lexical-gustatory synesthesia. There appears to be a strongly linked genetic component to neurological cross-linking phenomenon.<ref name=Haywood /> <ref name=Brang>{{cite journal|last=Brang|first=David|coauthors=V.S. Ramachandran|title=Survival of the Synesthesia Gene: Why Do People Hear Colors and Taste Words?|journal=PLoS Biology|year=2011|month=November|volume=9|issue=11|doi=10.1371/journal.pbio.1001205|url=http://cogns.northwestern.edu/dbrang/images/Brang_PlosBiology_2011.pdf}}</ref> Lexical-gustatory synesthesia and other forms of synesthesia are familial, meaning that they are passed on through a family<ref name=Simner/Ward /><ref name=SimnerReview /><ref name=Logie /><ref name=Haywood /><ref name=Richer /> As many as 40% of synesthetes have an immediate family member with synesthesia.<ref name=Brang /> For example, PS’s mother also had lexical gustatory synesthesia.<ref name=Richer /> One study suggests that there could be some sort of synesthesia gene passed through families that encodes for a predisposition to synthesia but not necessarily its expression. Further studies into determining the exact synthesia gene have not been successful, but it is possible that the over-expression of the serotonin 2A receptor on chromosome 13 resulting in a high receptor density could be the culprit.<ref name=Brang /> |
||
==Implications on Brain Function== |
==Implications on Brain Function== |
||
It is believed that the same neurological pathways operate in both persons with synesthesia and neurologically normal individuals. These pathways are just over-exaggerated in those with synesthesia<ref name=Simner/Ward /><ref name=SimnerReview /> |
|||
===Studies in neurologically normal persons=== |
===Studies in neurologically normal persons=== |
||
It has been shown that neurologically normal persons as young as 2.5 years of age demonstrate a type of synesthetic crossmodal associations. In 1929, Wolfgang Köhler ran an experiment in which a group of native spanish speakers would assign the name “takete” or “baluba” to a set of round or jagged shapes. It was concluded that people had a strong preference to calling the jagged shapes “takete” rather than “baluba”. Many scientists today think this is a synesthetic crossmodal association between the shape of the object and the phonemic inflection that the word makes when forming the word in the mouth. A similar “bouba” and “Kiki” food-word association study tested the synesthetic crossmodal associations of words and food tastes in neurologically normal participants. It was found that the participants could pick out certain abstract clues from the the different foods tasted and associate them in a significant manner to meaningless non-words. <ref name=Gallace>{{cite journal|last=Gallace|first=Alberto|coauthors=E. Boschin, C. Spence|title=On the taste of "Bouba" and "Kiki": An exploration of word-food associations in neurologically normal participants|journal=Cognitive Neuroscience|year=2011|volume=2|issue=1|pages=34-46|doi=10.1080/17588928.2010.516820}}</ref> |
It has been shown that neurologically normal persons as young as 2.5 years of age demonstrate a type of synesthetic crossmodal associations. In 1929, Wolfgang Köhler ran an experiment in which a group of native spanish speakers would assign the name “takete” or “baluba” to a set of round or jagged shapes. It was concluded that people had a strong preference to calling the jagged shapes “takete” rather than “baluba”. Many scientists today think this is a synesthetic crossmodal association between the shape of the object and the phonemic inflection that the word makes when forming the word in the mouth. A similar “bouba” and “Kiki” food-word association study tested the synesthetic crossmodal associations of words and food tastes in neurologically normal participants. It was found that the participants could pick out certain abstract clues from the the different foods tasted and associate them in a significant manner to meaningless non-words. <ref name=Gallace>{{cite journal|last=Gallace|first=Alberto|coauthors=E. Boschin, C. Spence|title=On the taste of "Bouba" and "Kiki": An exploration of word-food associations in neurologically normal participants|journal=Cognitive Neuroscience|year=2011|volume=2|issue=1|pages=34-46|doi=10.1080/17588928.2010.516820}}</ref> |
||
Revision as of 08:01, 27 November 2013
Lexical-gustatory synesthesia is a rare form of synesthesia in which both spoken and written language causes individuals to experience an automatic and highly consistent associated taste.[1] The taste is often experienced as a complex mixture of both temperature and texture. For example, in a particular synaesthete JIW, the word jail would taste of cold, hard bacon.[2][3] Synesthetic tastes are evoked by an inducer/concurrent complex. The inducer is the stimulus that activates the sensation and the taste experience is the concurrent.[4]
Experimental Studies
There are many scientific standards in use to determine if a person actually has the genuine neurological condition of lexical-gustatory synesthesia. Scientists check for the behavioral hallmark of a significantly higher retest consistency after at least a year compared to control groups. Another scientific standard method to determine the legitimacy of ones synesthesia is to use Functional magnetic resonance imaging or functional MRI (fMRI) to determine which areas of the brain are active during the scan. [1][2][5] A final method utilized by the prominent neuroscientist, V.S. Ramachandran, is the galvanic skin response (GSR). The GSR measures any fluctuations in the electrical resistance of skin. A high GSR could indicate that a person my be lying about their synesthesia condition. No GSR indicates that a person would be telling the truth about their synesthesia. [6]
Experiences and Phonological Roots
There are many forms of lexical-gustatory synesthesia and the various taste sensations linked to the neurological condition vary widely from synesthete to synesthete.[7] Examples of many well known synesthetic taste experiences are recorded in case studies with singular participants that demonstrate the variability of the condition. In one case, PS is a patient that has taste experiences that happen in her head and not her mouth.[8] Her tastes usually have both texture and temperature associated with the sensation.[2]Some forms of lexical-gustatory synesthesia are triggered by thinking of the word's meaning, rather than its sound or spelling. Others are triggered by hearing or reading an inducer word.[1] In many forms, more well known words and words used with a higher frequency are more likely to have a strong taste association [2] [7] The phonological roots associated with this form of synesthesia drive the current research on lexical-gustatory synesthesia to determine which parts of the brain are active in synesthetes causing the neurological cross-talk condition and how the findings may relate to neurologically normal persons.[2] [3]
Tip of the tongue studies
Tip of the tongue (TOT) studies refer to studies when higher order characteristics of words such as the meaning, concept, or its syntactic category are retrieved from memory. These characteristics are called the lemma of a word. Tip of tongue studies have shown that a word’s lemma may be responsible for eliciting a taste sensation, not its phonologic sound or spelling. Further TOT studies determined the possibility that during TOT states, lexemes could be partially activated to yield phoneme-triggered tastes.[1][2] [5]
Case Studies
JIW
JIW is a synesthete who automatically experiences tastes in and around his mouth when he hears words. He describes his tastes to be very similar to real tastes experienced when eating, but without the substance. JIW’s case study to evaluate the consistency in a series of re-tests began in the late 1970s. In 2006, exactly 27 years after his initial study, JIW and a group of ten controls who were not a part of the original study were re-tested using words from original 1970s study. The controls were instructed that they would be immediately retested on their inducer-concurrent associations. The results of the 2006 study indicated that the controls had a mean consistency of about 47.9% while JIW had maintained a consistency of 100%.[2][4]
JIW’s tastes are largely correlated to foods that he would have eaten as a child. He is around ten times more likely to associate a word to the taste of chocolate than he would to the taste of something he experienced as an adult, such as a beer or coffee. For example, when JIW hears a common word such as this, he experiences the tastes of ‘bread soaked in tomato soup’. Bread and tomato soup would have been common flavors JIW experienced in his childhood. It is hypothesized that some or all forms of lexical-gustatory synesthesia may trigger during early childhood development and lead to the over-representation of the flavors of childhood foods.[2][4]
Both consistency studies and fMRI scans have validated JIW’s lexical-gustatory synesthesia. A fMRI scan showed the bilateral activation of the Broca’s area 43 in the brain during JIW’s taste experiences. The Broca’s area 43 is a part of the primary gustatory cortex which is responsible for the perception of taste. Further studies of the underlying brain regions involved in synesthetes like JIW could aid in identifying the root physiological mechanisms involved in lexical-gustatory synesthesia.[2][4]
SC
SC is a synesthete who automatically experiences smells, tastes, and feelings of textures in her mouth and throat when she reads, speaks, or hears language, music, and certain environmental sounds. In SC’s case study, researchers utilized fMRI to determine the areas of the brain that were activated during her synesthetic experiences. They compared areas of activation in SC’s brain to those found in literature for other synesthetes, speech processing, language, and sound processing. In SC’s scans, two important regions of the brain were largely activated during her taste sensations: the left anterior insula and the left superior parietal lobe. The scans led researchers to speculate that the anterior insula may play a role in SC’s taste experiences while the superior parietal lobe binds together all of the sensory information for processing. Based off the findings of this study and others like it, it could be possible to determine the type of inducer that leads to synesthetic sensations based on the patterns of brain activity.[3]
Possible Neural Basis
Many modern theories suggest that synesthesia is a result of differences that occur during the neuro-developmental process of maturation. It is possible that incomplete synaptic pruning during childhood development could lead to the continued maintenance of connections that are normally served in the process. The maintenance of these connections would then lead to the cross-linking of ares in the brain that do not normally interact with one another and the possible mixing of senses. fMRIs are used to study these possible connections.[2][5] Another possible neurological mechanism that may contribute to synesthesia is an increased structural connectivity in the brains of synesthetes as shown using diffusion tensor imaging (DTI).[5]
Possible Genetic Basis
Approximately 2%-4% of the population has some form of synesthesia. An even smaller percentage, around 0.2% or lower, have lexical-gustatory synesthesia. There appears to be a strongly linked genetic component to neurological cross-linking phenomenon.[5] [9] Lexical-gustatory synesthesia and other forms of synesthesia are familial, meaning that they are passed on through a family[1][2][4][5][8] As many as 40% of synesthetes have an immediate family member with synesthesia.[9] For example, PS’s mother also had lexical gustatory synesthesia.[8] One study suggests that there could be some sort of synesthesia gene passed through families that encodes for a predisposition to synthesia but not necessarily its expression. Further studies into determining the exact synthesia gene have not been successful, but it is possible that the over-expression of the serotonin 2A receptor on chromosome 13 resulting in a high receptor density could be the culprit.[9]
Implications on Brain Function
It is believed that the same neurological pathways operate in both persons with synesthesia and neurologically normal individuals. These pathways are just over-exaggerated in those with synesthesia[1][2]
Studies in neurologically normal persons
It has been shown that neurologically normal persons as young as 2.5 years of age demonstrate a type of synesthetic crossmodal associations. In 1929, Wolfgang Köhler ran an experiment in which a group of native spanish speakers would assign the name “takete” or “baluba” to a set of round or jagged shapes. It was concluded that people had a strong preference to calling the jagged shapes “takete” rather than “baluba”. Many scientists today think this is a synesthetic crossmodal association between the shape of the object and the phonemic inflection that the word makes when forming the word in the mouth. A similar “bouba” and “Kiki” food-word association study tested the synesthetic crossmodal associations of words and food tastes in neurologically normal participants. It was found that the participants could pick out certain abstract clues from the the different foods tasted and associate them in a significant manner to meaningless non-words. [10]
In popular culture
Books
Truong, Monique (2011) "Bitter in the Mouth"[11]. The main character, Linda, can taste words.
References
- ^ a b c d e f Simner, Julia (23). "The taste of words on the tip of the tounge". Nature. 444: 438. doi:10.1038/444438a.
{{cite journal}}: Check date values in:|date=and|year=/|date=mismatch (help); Unknown parameter|coauthors=ignored (|author=suggested) (help); Unknown parameter|month=ignored (help) - ^ a b c d e f g h i j k l Simner, Julia (29). "Beyond perception: synaesthesia as a psycholinguistic phenomenon". TRENDS in Cognitive Sciences. 11 (1): 23–29. doi:10.1016/j.tics.2006.10.010.
{{cite journal}}: Check date values in:|date=and|year=/|date=mismatch (help); Cite has empty unknown parameter:|1=(help); Unknown parameter|month=ignored (help) - ^ a b c Colizoli, Olympia (23). "A taste for words and sounds: a case of lexical-gustatory and sound-gustatory synesthesia". Frontiers in Psychology. 4 (775). doi:10.3389/fpsyg.2013.00775. PMID PMC3806228.
{{cite journal}}: Check|pmid=value (help); Check date values in:|date=and|year=/|date=mismatch (help); Unknown parameter|coauthors=ignored (|author=suggested) (help); Unknown parameter|month=ignored (help)CS1 maint: unflagged free DOI (link) - ^ a b c d e Simner, Julia (2007). "Synaesthetic Consistency Spans Decades in a Lexical-Gustatory Synaesthete". Neurocase. 13: 358–365. doi:10.1080/13554790701851502.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ a b c d e f Simner, Julia (2011). "Tasty non-words and neighbors: The cognitive roots of lexical-gustatory synaesthesia". Cognition. 110: 171–181. doi:10.1016 b/j.cognition.2008.11.008.
{{cite journal}}: Check|doi=value (help); Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ Ramachandran, V.S. (2011). The Tell-Tale Brain: A Neuroscientist's Quest for What Makes Us Human. New York, NY: W.W.Norton & Company, Inc. pp. 75–116. ISBN 978-0-393-07782-7.
- ^ a b Bankieris, Kaitlyn (2013). "Sound symbolism in synesthesia: Evidence from a lexical-gustatory synesthete". Neurocase: The Neural Basis of Cognition. doi:10.1080/13554794.2013.826693. PMID 23972101.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ a b c Richer, Francois (4). "Bidirectional lexical-gustatory synesthesia". Consciousness and Cognition. 20: 1738–1743. doi:10.1016/j.concog.2010.12.015.
{{cite journal}}: Check date values in:|date=and|year=/|date=mismatch (help); Unknown parameter|coauthors=ignored (|author=suggested) (help); Unknown parameter|month=ignored (help) - ^ a b c Brang, David (2011). "Survival of the Synesthesia Gene: Why Do People Hear Colors and Taste Words?" (PDF). PLoS Biology. 9 (11). doi:10.1371/journal.pbio.1001205.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help); Unknown parameter|month=ignored (help)CS1 maint: unflagged free DOI (link) - ^ Gallace, Alberto (2011). "On the taste of "Bouba" and "Kiki": An exploration of word-food associations in neurologically normal participants". Cognitive Neuroscience. 2 (1): 34–46. doi:10.1080/17588928.2010.516820.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ Truong, Monique (2011). Bitter in the Mouth. Random House Trade Paperbacks. ISBN 0812981324.