h warm colors (more toward the red) denoting high dissimilarity and cold colors (more toward blue) denoting high similarity. That is, the warmer the color of a cell, the more dissimilar the two stimuli are in terms of how they were associated with the tastes. Therefore, the diagonal of each matrix is colored blue to represent the perfect similarity of each stimulus’ taste-pattern with itself.
These RDMs also allowed us to examine whether any color, shape, and/or texture were associated with the same taste(s). Interestingly, the texture (smooth, rough) has similar taste-patterns with the white color for the participants from India, Malaysia, and the USA, but not for the Chinese participants. What is more, a sub-group of colors (green, purple, orange, red, yellow, and pink) and a sub-group of shapes (star, moon, and hear) had similar taste-patterns for the Indian group, whereas the USA and Malaysian groups also both showed this pattern with the color pink and purple (and only pink for the Chinese group).
Last but by no means least, we combined the data from all the groups, and calculated a cross-cultural RDM (see Figure 7). Interestingly, this RDM shows that all the countries are approximately equally dissimilar from, or similar to, one another. Figure 8 also shows each group’s ratings of how confident they were that other people would choose the same taste term for each visual stimulus as they had. Across the four groups of participants, the percentages of those choosing the answers very confident, confident, uncertain, not confident, and very unconfident are 12, 48, 31, 7, and 2%, respectively.
FIGURE 7. The cross-cultural RDM. The color of each cell stands for the dissimilarity between the taste-associated patterns of the culture groups in the respective row and column, with warm colors denoting high dissimilarity and cold colors denoting low dissimilarity. The diagonal of this matrix is still colored blue because of the perfect similarity of each group’s taste-pattern with itself.
FIGURE 8. Confidence ratings for each group of participants. When choosing a taste term to match the visual stimuli, the participants were also asked to indicate how confident they were that other people would respond in the same fashion as they had. Note that the percentage of the very unconfident, unconfident, uncertain, confident, and very confident chosen for the answer are represented by the fill-in colors purple, blue, yellow, red, and green, respectively.
The results of the present study revealed a number of intriguing crossmodal associations between the basic tastes and certain visual features across the four groups of participants from different countries, including (1) the fact that a bitter taste was matched with black, the cross, ellipse, rectangle, and square shapes, (2) the salty taste was matched with the color white, and the smooth and rough textures, (3) the sour taste was matched with the color green, and (4) the sweet taste was matched with the color pink, the cloud, heart, and star shapes. By contrast, the results did not show that the umami taste was strongly associated with any color, shape, or texture in any of the groups of participants. Considering that the umami taste was recognized as one of the basic tastes long after the other four were recognized (Kawamura and Kare, 1987; Mouritsen and Styrbaek, 2014), it is difficult to differentiate whether the participants were simply not familiar with this term, were confused with the usage of this term (namely taste confusion, see O’Mahony et al., 1979), or this taste was just not strongly associated with any one of the visual features presented in this study.
It should be noted that language plays an important role in the matching task, and the participants were asked to make a forced choice. Therefore, the nature of the matching task might elicit more linguistic correspondences than other types of correspondences (see Melara and Marks, 1990; Martino and Marks, 2001; for comparisons between linguistic and non-linguistic correspondences). By contrast, testing with real tasta