Last year, I wrote two really long, boring posts about V.S. Ramachandran’s ten principles of art. Those principles, mostly drawn from research on vision, included things like peak shift, symmetry, and contrast. It turns out Ramachandran may have missed a much simpler principle: people dig curves. At least, they prefer them to sharp angles.
Why curves? Well, Moshe Bar and Maital Neta1 hypothesize that “sharp transitions in a contour might convey a sense of threat, on either a conscious or a nonconscious level, and thus trigger a negative bias” (p. 645). This preference, they argue, should show up very quickly (after viewing something for a few milliseconds). In order to test this, they collected images of 140 pairs of familiar objects (including 23 pairs of English letters) specifically chosen because they were not associated with positive or negative emotions, along with 140 pairs of “meaningless patterns.” In each pair of familiar objects and meaningless patterns, one of the items had curved contours, and the other had sharp contours. They also included 80 familiar objects with both sharp and curved contours. Examples of each item type can be seen in the figure below (Bar and Neta’s Figure 1, p. 646).

They then presented each participant with one object or pattern from each pair for 84 ms, and asked them to indicate whether they liked or disliked the image. People liked the familiar objects more than the meaningless patterns, but for both item types, they liked the curved items more than the sharp-angled items. The items with both curved and sharp-angled contours fell in between the two.
So what does this mean, in practical terms? It probably does have some implications for art, and Bar and Neta note that it may also have implications for consumer behavior. It explains why I liked Jaguars more than Volvos in the 80s, at least. Since the evaluations took place after such short viewing times, the participants weren’t aware of the reasons for their preferences. So it also means that curves and sharp-angles (and perhaps other features associated with threat or other negative emotions) may often influence our preferences or first impressions without us realizing it.
1Bar, M., & Neta, M. (2006). Humans prefer curved visual objects. Psychological Science, 17(8), 645-648.