 Unitization is the counterpart to differentiation. In unitization, a person comes to perceive as a single property, what they previously perceived as two or more distinct properties. One example of unitization is the perception of written words. When we perceive a written word in English, we do not simply perceive two or more distinct letters. Rather, we perceive those letters as a single word. Put another way, we perceive written words as a single unit (see Smith &amp; Haviland 1972). This is not the case with non-words. When we perceive short strings of letters that are not words, we do not perceive them as a single unit. Goldstone and Byrge provide a list of items for which there is empirical evidence of such unitization: 