For quite some time, people have been intrigued by the connection between certain sounds and colors, pondering why they seem to complement each other. In individuals with sound-color synesthesia, hearing a specific sound consistently triggers the experience of a particular color (Ward, 2013). Even those without synesthesia often possess strong instincts about which sounds and colors harmonize. There's an ongoing discussion about whether these cross-modal correspondences share mechanisms with synesthesia (e.g., Lacey, Martinez, McCormick, & Sathian, 2016; Spence, 2011), but they undeniably influence perception and our language. For instance, it feels natural to describe high-frequency sounds as "bright," though there's no inherent reason to link visual brightness with auditory frequency. The prevalence of such metaphors underscores the significance of cross-modal correspondences not just in human perception but also in language (Bankieris & Simner, 2015; Ramachandran & Hubbard, 2001; Sidhu & Pexman, 2018). Iconicity, which involves the meaningful association between sound and meaning, enriches our comprehension of how human language and cognition have evolved. It also sheds light on how language evolves culturally by revealing various mechanisms influencing word formation and sound change. Lexical iconicity, or sound symbolism, mainly affects concepts related to description or perception.⁂
There are findings in the literature that the mechanisms used during crossmodal correspondences are consistent with the ones used by synaesthetic people.
According to Ward et all (2006) both synaesthetes and non-synaesthetes associate higher pitches with lighter colors.
For reference:
The Munsell Value signifies the brightness of a color, indicating how light or dark it appears. The value scale spans from 0 for absolute black to 10 for absolute white. Colors such as black, white, and the various shades of gray in between are termed "neutral colors" because they lack any distinct hue. Colors that possess a hue are referred to as "chromatic colors." The value scale is applicable to both chromatic and neutral colors alike. In the book of color, Munsell's Nearly Neutral chart illustrates the value scale for all neutral colors.
Lacey S, Martinez M, McCormick K, Sathian K. Synesthesia strengthens sound-symbolic cross-modal correspondences. Eur J Neurosci. 2016 Nov;44(9):2716-2721. doi: 10.1111/ejn.13381. Epub 2016 Sep 15. PMID: 27564319; PMCID: PMC5089906.
Ward J. Synesthesia. Annu Rev Psychol. 2013;64:49-75. doi: 10.1146/annurev-psych-113011-143840. Epub 2012 Jun 29. PMID: 22747246.
Spence, C. Crossmodal correspondences: A tutorial review. Atten Percept Psychophys 73, 971–995 (2011). https://doi.org/10.3758/s13414-010-0073-7