survival point of view, this may be important for the continued search for predators. Ramachandran suggests for the same reason that a model whose hips and breasts are about to be revealed is more provocative than one who is already completely naked. A meaning that is implied is more alluring than one that is explicit. The generic viewpoint The visual system dislikes interpretations which rely on a unique vantage point. Rather it accepts the visual interpretation for which there is an infinite set of viewpoints that could produce the class of retinal images. For example, in a landscape image, it will interpret an object in the foreground as obscuring an object in the background, rather than assuming that the background figure has a piece missing. In theory, if an artist is trying to please the eye, they should avoid such coincidences. However, in certain applications, the violation of this principle can also produce a pleasing effect. Visual metaphors Ramachandran defines a metaphor as a mental tunnel between two concepts that appear grossly dissimilar on the surface, but instead share a deeper connection. Similar to the effects of perceptual problem solving, grasping an analogy is rewarding. It enables the viewer to highlight crucial aspects that the two objects share. Although it is uncertain whether the reason for this mechanism is for effective communication or purely cognitive, the discovery of similarities between superficially dissimilar events leads to activation of the limbic system to create a rewarding process. Support for this view is highlighted by the symptoms of Capgras delusion, where sufferers experience reduced facial recognition due to impairments in the connections from the inferotemporal cortex to the amygdala, which is responsible for emotions. The result is that a person no longer experiences the warm fuzzy feeling when presented with a familiar face. A person's 'glow' is lost through what is suggested as due to the lack of limbic activation. Symmetry The aesthetic appeal of symmetry is easily understandable. Biologically it is important during the detection of a predator, location of prey, and the choosing of a mate as all of these tend to display symmetry in nature. It complements other principles relating to the discovering of information rich objects. Additionally, evolutionary biologists suggest that the predisposition towards symmetry is because biologically, asymmetry is associated with infection and disease, which can lead to poor mate selection. However, departures from symmetry in visual art