When roundness is connected to symmetry as seen in a circle, it has a meaning in the depth dimension and perceived as cheerful and pleasant. While straight corners are perceived as more serious (Poffenberger en Barrows, 1924). Lakoff and Johnson (1999) saw that there are many proverbs and sayings that have to do with form characteristics and emotions. Round: regulated, completed, ready. (Michiels, I. editorial)
Square/rounded has an important influence on the function of the size of an angle. Rounded corners are experienced more cheerfully, while straight angles are perceived as more serious (Poffenberger en Barrows, 1924). Round and square are also related to activation. Roundness in parts of utensils or interfaces can indicate a button, where activation is needed. Sharp roundness can therefore trigger alertness and induce action.