 Previous research, suggest that this trend of complexity could also be associated with ability to understand, in which observers prefer artwork that is not too easy or too difficult to comprehend.Other research both confirms and disconfirms predictions that suggest that individual characteristics such as artistic expertise and training can produce a shift in the inverted U-shape distribution.A general trend shows that the relationship between image complexity and pleasantness ratings form an inverted-U shape graph (see Expertise section for exceptions).