I was fascinated when I first read Ramachandran's article about kiki bouba effect, and I was wondering if cats experience the same thing... As Ramachandran proved, our angular gyrus is responsible for this phenomenon, and I found a part of cat's brain, named FAES, which has neurons that spike for auditory and visual stimuli. Does anyone know if they experience it?
The bouba/kiki effect is the phenomenon that about 95% of subjects assign the name bouba to a blobby form, and the name kiki to a pointy shape (Fig. 1).
Fig. 1. Kiki and bouba, at least in 95% of the people. source: Synesthesia Test
It is thought that the reason behind the strong preference is that the sharp changes in visual direction of the lines in the left-hand panel in Fig. 1 mimics the sharp phonemic inflections of the sound kiki, as well as the sharp inflection of the tongue on the palate. Ramachandran poses that the bouba/kiki effect provides a clue for understanding the origins of proto-language, for it suggests that there sounds are mapped on to objects. Ramachandran poses that the representation of certain lip and tongue movements in motor brain areas are mapped in non-arbitrary ways onto certain sound inflections and phonemic representations in auditory regions and the latter in turn may have links to an external object’s visual appearance. These factors may have co-evolved, forming a possible origin of proto-language (Ramachandran & Hubbard, 2001).
To get to your question: cats can't talk. Their vocalizations are relatively restricted, adding up to 16 different sounds. They include the familiar meows, hissing when angry and purring when happy. The purring comes from deep within the body and isn't related to speech at all. The hissing sounds a bit like an /h/ and the meows include more varieties. However, the variability in 'meows' is largely due to intonations (source: The Independent), and not so much the phonemes. Phonemes are: '[...] sound[s], or set of similar speech sounds, which are perceived as a single distinctive sound by speakers of the language or dialect in question. For example, the "c/k" sounds in cat and kitten represent the English phoneme /k/.
Human speech is extremely diverse and is produced by the interplay of various organs, includes lip, tongue and glottal movements that change the way the vocal cords produce sounds. There are 36 phonemes (speech sounds) recognized in English.
The bouba/kiki effect hinges strongly on the phonemes /b/ and /k/ and, perhaps, /i/ and /ou/. Both in Ramachandran & Hubbard's experiment (bouba/kiki) (Ramachandran & Hubbard, 2001) and the original study by Kohler (baluba/takete) (reviewed shortly in Ozturk et al. (2013)).
Cats don't have that kind of repertoire of phonemes. So regardless the similarity in some brain areas, I dare to say a bouba/kiki or baluba/takete effect can never be found in cats. I realize this is a rather mechanistic approach to the question and I am indeed not saying that cats cannot experience synesthesia. But that's another question...