.
- Sound-colour synesthesia: With sound colour synesthesia, sounds will trigger colour visualizations. The perceived colours will usually appear in a generic shape. .
- Number-form synesthesia: This synesthesia will form a visual number map when thinking about numbers. .
- Lexical- gustatory synesthesia: This type of synesthesia is very rare, but can occur. Different tastes will occur when they hear certain words or phonemes. For example, when one hears the word "pencil" it may evoke the taste of bacon.
The types of synaesthesia stated above are just a few common ones that occour between two sensory pathways; but throughout Ramachandrans and Hubbard's article these types of synaesthesia are not mentioned. The types of synaesthesia that the two did use to support their theory consisted of the following: synaesthesia between appearance & sound contour, synaesthesia between sound contour & vocalizations, and synkinaesia.
The first example that was given to help prove that language origins come from synaesthesia was the boubi/kiki effect test. This test was originally invented by Kohler(1929; 1947) and then again revisited by Werner(1934; 1957). So for example, if one were to say in Martian language one of these images is names bouba and the other is named kiki, which name would you associate with which image? The results were that 95% of people chose the left image as kiki and the right as bouba, even though they have never seen these stimuli before. The explanation they gave for this was the following: People usually chose the left image as 'kiki' because the images sharp changes in visual direction of the lines mimic the sharp phonemic inflections of the sound 'kiki' as well as the sharp inflection of the tongue & palate. The image on the right is usually chosen as 'bouba' because the rounded contours of the figure mimic the rounded auditory inflection of bouba.
