Though Birkhoff’s model does include important components of aesthetics, it does not provide for emotional reactions from interpretation. Birkhoff himself made reference to this, when he pointed out that certain polygons might have associations not accounted for in M that could influence judgement. For example, a cross-shaped polygon may have “positive connotative associations1 .” Later, Berlyne incorporated meaning, as well as complexity and order (or the related property, balance) in the model described next
