Ideasthesia (alternative spelling ideaesthesia) is a
neuropsychological
Neuropsychology is a branch of psychology concerned with how a person's cognition and behavior are related to the brain and the rest of the nervous system. Professionals in this branch of psychology focus on how injuries or illnesses of the brai ...
phenomenon in which activations of
concept
A concept is an abstract idea that serves as a foundation for more concrete principles, thoughts, and beliefs.
Concepts play an important role in all aspects of cognition. As such, concepts are studied within such disciplines as linguistics, ...
s (inducers) evoke
perception
Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous syste ...
-like sensory experiences (concurrents). The name comes from the
Ancient Greek
Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...
() and (), meaning 'sensing concepts' or 'sensing ideas'. The notion was introduced by neuroscientist Danko Nikolić, but can be seen in examples in the Ethics of Spinoza (especially in the third part of the Ethics), as an alternative explanation for a set of phenomena traditionally covered by
synesthesia
Synesthesia (American English) or synaesthesia (British English) is a perceptual phenomenon in which stimulation of one sensory or cognitive pathway leads to involuntary experiences in a second sensory or cognitive pathway. People with sy ...
.
While ''synesthesia'' meaning 'union of senses' implies the association of two sensory elements with little connection to the cognitive level,
empirical evidence
Empirical evidence is evidence obtained through sense experience or experimental procedure. It is of central importance to the sciences and plays a role in various other fields, like epistemology and law.
There is no general agreement on how the ...
indicated that most phenomena linked to synesthesia are in fact induced by
semantic
Semantics is the study of linguistic Meaning (philosophy), meaning. It examines what meaning is, how words get their meaning, and how the meaning of a complex expression depends on its parts. Part of this process involves the distinction betwee ...
representations. That is, the
linguistic meaning of the stimulus is what is important rather than its sensory properties. In other words, while synesthesia presumes that both the trigger (inducer) and the resulting experience (concurrent) are of sensory nature, ideasthesia presumes that only the resulting experience is of sensory nature while the trigger is semantic.
[Dixon, M.J., Smilek, D., Duffy, P.L., Zanna, P. M., Merikle, P. M. (2006) The Role of Meaning in Grapheme-Colour Synaesthesia, ''Cortex'' 42: 243-252.][Mroczko A., T. Metzinger, W. Singer, D. Nikolić (2009) Immediate transfer of synesthesia to a novel inducer. ''Journal of Vision'', 9: 2521-2528.][Simner, J.; Ward, J. (2006) The taste of words on the tip of the tongue, ''Nature'' 444: 438.][Nikolić, D., U.M. Jürgens, N. Rothen, B. Meier, A. Mroczko (2011) Swimming-style synesthesia. ''Cortex'', 47(7):874-879.][Chiou, R., Rich N.A. (2014) The role of conceptual knowledge in understanding synaesthesia: Evaluating contemporary findings from a ‘hub-and-spoke’perspective. ''Frontiers in Psychology'', 5: 105.]
Research has later extended the concept to topics other than synesthesia, and since it turned out to be applicable to everyday
perception
Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous syste ...
, the concept has developed into a theory of how we perceive. For example ideasthesia has been applied to the theory of art and could bear important implications in explaining human conscious
experience
Experience refers to Consciousness, conscious events in general, more specifically to perceptions, or to the practical knowledge and familiarity that is produced by these processes. Understood as a conscious event in the widest sense, experience i ...
, which, according to ideasthesia, is grounded in how we activate
concepts
A concept is an abstract idea that serves as a foundation for more concrete principles, thoughts, and beliefs.
Concepts play an important role in all aspects of cognition. As such, concepts are studied within such disciplines as linguistics, psy ...
.
[Mroczko-Wąsowicz, A., Nikolić D. (2014) Semantic mechanisms may be responsible for developing synesthesia. ''Frontiers in Human Neuroscience'' 8:509. ]
Examples and evidence

A common example of synesthesia is the association between
grapheme
In linguistics, a grapheme is the smallest functional unit of a writing system.
The word ''grapheme'' is derived from Ancient Greek ('write'), and the suffix ''-eme'' by analogy with ''phoneme'' and other emic units. The study of graphemes ...
s and colors, usually referred to as
grapheme–color synesthesia. Here, letters of the alphabet are associated with vivid experiences of color. Studies have indicated that the perceived color is context-dependent and is determined by the extracted meaning of a stimulus. For example, an ambiguous stimulus '5' that can be interpreted either as 'S' or '5' will have the color associated with 'S' or with '5', depending on the context in which it is presented. If presented among numbers, it will be interpreted as '5' and will associate the respective color. If presented among letters, it will be interpreted as 'S' and will associate the respective synesthetic color.
Evidence for grapheme-color synesthesia comes also from the finding that colors can be flexibly associated to graphemes, as new meanings become assigned to those graphemes. In one study synesthetes were presented with
Glagolitic
The Glagolitic script ( , , ''glagolitsa'') is the oldest known Slavic alphabet. It is generally agreed that it was created in the 9th century for the purpose of translating liturgical texts into Old Church Slavonic by Saints Cyril and Methodi ...
letters that they had never seen before, and the meaning was acquired through a short writing exercise. The Glagolitic graphemes inherited the colors of the corresponding Latin graphemes as soon as the Glagolitic graphemes acquired the new meaning.
In another study, synesthetes were prompted to form novel synesthetic associations to graphemes never seen before. Synesthetes created those associations within minutes or seconds – which was time too short to account for creation of new physical connections between color representation and grapheme representation areas in the brain, pointing again towards ideasthesia. Although the time course is consistent with postsynaptic
AMPA receptor
The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA receptor, AMPAR, or quisqualate receptor) is an ionotropic receptor, ionotropic glutamate receptor (iGluR) and predominantly sodium ion channel that mediates fast excitator ...
upregulation or
NMDA receptor
The ''N''-methyl-D-aspartate receptor (also known as the NMDA receptor or NMDAR), is a glutamate receptor and predominantly Ca2+ ion channel found in neurons. The NMDA receptor is one of three types of ionotropic glutamate receptors, the other ...
coactivation, or both, which would imply that the realtime experience is invoked at the synaptic level of analysis prior to establishment of novel wiring per se, a very intuitively appealing model.
For
lexical–gustatory synesthesia evidence also points towards ideasthesia: in lexical-gustatory synesthesia, verbalisation of the stimulus is not necessary for the experience of concurrents. Instead, it is sufficient to activate the concept.
Another case of synesthesia is swimming-style synesthesia in which each swimming style is associated with a vivid experience of a color.
These synesthetes do not need to perform the actual movements of a corresponding swimming style. To activate the concurrent experiences, it is sufficient to activate the concept of a swimming style (e.g., by presenting a photograph of a swimmer or simply talking about swimming).
It has been argued that grapheme-color synesthesia for
geminate consonants also provides evidence for ideasthesia.
In pitch-color synesthesia, the same tone will be associated with different colors depending on how it has been named; do-sharp (i.e. di) will have colors similar to do (e.g., a reddish color) and re-flat (i.e. ra) will have color similar to that of re (e.g., yellowish), although the two classes refer to the same tone. Similar semantic associations have been found between the acoustic characteristics of vowels and the notion of size.
There are synesthetic experiences that can occur just once in a lifetime, and are thus dubbed one-shot synesthesia. Investigation of such cases has indicated that such unique experiences typically occur when a synesthete is involved in an intensive mental and emotional activity such as making important plans for one's future or reflecting on one's life. It has been thus concluded that this is also a form of ideasthesia.
In normal perception
Since 2013, it has been suggested that the
Bouba/Kiki phenomenon is a case of ideasthesia.
[Gómez Milán, E., Iborra, O., de Córdoba, M.J., Juárez-Ramos V., Rodríguez Artacho, M.A., Rubio, J.L. (2013) The Kiki-Bouba effect: A case of personification and ideaesthesia. ''The Journal of Consciousness Studies.'' 20(1-2): pp. 84-102.] Most people will agree that the star-shaped object on the left is named Kiki and the round one on the right Bouba.
[Ramachandran, VS & Hubbard, EM (2001) Synaesthesia: A window into perception, thought and language. ''Journal of Consciousness Studies'' 8(12): 3–34.] It has been assumed that these associations come from direct connections between visual and auditory cortices.
For example, according to that hypothesis, representations of sharp inflections in the star-shaped object would be physically connected to the representations of sharp inflection in the sound of Kiki. However, Gomez et al.
have shown that Kiki/Bouba associations are much richer as either word and either image is associated semantically to a number of concepts such as white or black color, feminine vs. masculine, cold vs. hot, and others. These sound–shape associations seem to be related through a large overlap between
semantic network
A semantic network, or frame network is a knowledge base that represents semantic relations between concepts in a network. This is often used as a form of knowledge representation. It is a directed or undirected graph consisting of vertices, ...
s of Kiki and star-shape on the one hand, and Bouba and round-shape on the other hand. For example, both Kiki and star-shape are clever, small, thin and nervous. This indicates that behind Kiki-Bouba effect lies a rich semantic network. In other words, our sensory experience is largely determined by the meaning that we assign to stimuli. Food description and wine tasting is another domain in which ideasthetic association between flavor and other modalities such as shape may play an important role. These semantic-like relations play a role in successful marketing; the name of a product should match its other characteristics.
Implications for development of synesthesia
The concept of ideasthesia bears implications for understanding
how synesthesia develops in children. Synesthetic children may associate concrete sensory-like experiences primarily to the abstract concepts that they have otherwise difficulties dealing with.
Synesthesia may thus be used as a cognitive tool to cope with the abstractness of the learning materials imposed by the educational system – referred to also as a "semantic vacuum hypothesis". This hypothesis explains why the most common inducers in synesthesia are graphemes and time units – both relating to the first truly abstract ideas that a child needs to master.
Implications for art theory
The concept of ideasthesia has been often discussed in relation to art, and also used to formulate a psychological theory of art.
[Nikolić D. (2016) Ideasthesia and art. In: Gsöllpointner, Katharina, et al. (eds.). 2016. Digital Synesthesia. A Model for the Aesthetics of Digital Art. Berlin/Boston: De Gruyter (http://ieet.org/index.php/IEET/print/11666)] According to the theory, we consider something to be a piece of art when experiences induced by the piece are accurately balanced with semantics induced by the same piece. Thus, a piece of art makes us both strongly think and strongly experience. Moreover, the two must be perfectly balanced such that the most salient stimulus or event is both the one that evokes strongest experiences (fear, joy, ... ) and strongest cognition (recall, memory, ...) – in other words, ''idea'' is well balanced with ''aesthesia''.
Ideasthesia theory of art may be used for psychological studies of
aesthetics
Aesthetics (also spelled esthetics) is the branch of philosophy concerned with the nature of beauty and taste (sociology), taste, which in a broad sense incorporates the philosophy of art.Slater, B. H.Aesthetics ''Internet Encyclopedia of Ph ...
. It may also help explain
classificatory disputes about art as its main tenet is that experience of art can only be individual, depending on person's unique knowledge, experiences and history.
There could exist no general classification of art satisfactorily applicable to each and all individuals.
Neurophysiology of ideasthesia
Ideasthesia is congruent with the theory of brain functioning known as
practopoiesis. According to that theory, concepts are not an emergent property of highly developed, specialized neuronal networks in the brain, as is usually assumed; rather, concepts are proposed to be fundamental to the very adaptive principles by which living systems and the brain operate.
A study using
magnetoencephalography
Magnetoencephalography (MEG) is a functional neuroimaging technique for mapping brain activity by recording magnetic fields produced by electric current, electrical currents occurring naturally in the human brain, brain, using very sensitive magn ...
has shown that color information is available in the brain signal ~200 milliseconds later when accessed via synesthesia in comparison to direct color perception, which is consistent with conceptual mediation.
[L. Teichmann, T. Grootswagers, D. Moerel, T. A. Carlson, A. N. Rich. (2021) Temporal dissociation of neural activity underlying synesthetic and perceptual colors. Proceedings of the National Academy of Sciences, 118 (6) e2020434118; ] The study supports the idea that synesthesia is a semantic phenomenon – i.e., ideasthesia.
See also
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References
External links
TED Ed videoexplaining ideasthesia
described by New Scientist
Audio Criticism & Ideasthesia*
YouTube videoof a lecture on ideasthesia at SoundThinking conference
{{Philosophy of mind, state=autocollapse
Behavioural sciences
Cognition
Neuropsychology
Synesthesia