5. Beiderman’s Geon theory attempts to explain how humans manage to recognize 3D shapes. The theory explains that a given view of an object can be represented as an arrangement of simple 3D shapes called geons, and is therefore FAT for the recognition of 3D objects. These geons can be combined to for meaningful arrangements in terms of object recognition. Just as the same group of letters can be combined to form entirely different words (as in “ant” and “tan”), the same group of geons can form entirely different objects (such as a pail and a mug). One strength of this theory is that geons are allowed some variation, whether it is orientation or ratio of height to width. Another strength is a modification to the theory called the viewer-centered approach. This theory proposes that we store a small number of views of 3D objects, and we are mentally able to rotate any given view towards one that matches a view located in our memory.

6. Gestalt psychology, in general, explains that humans have basic tendencies to organize what they see. We tend to see patterns, not just random arrangements of stimuli. In the figure-ground relationship, two areas, a figure and a ground, share a common boundary. The figure is dominant and has a distinct shape and clearly defined edges while the ground simply continues behind the figure. In an ambiguous figure-ground relationship, the figure and the ground reverse from time to time; sometimes the figure becomes the ground, and sometimes it’s the figure again. This tells us that the pattern is emanating from the mind (not strictly the stimulus) and therefore illustrates a top-down process.