Evidence from the last 20 years of work in cognitive psychology indicates that we use the letters within a word to recognize a word. Many typographers and other text enthusiasts Ive met insist that words are recognized by the outline made around the word shape. Some have used the term bouma as a synonym for word shape, though I was unfamiliar with the term. The term bouma appears in Paul Saengers 1997 book Space Between Words: The Origins of Silent Reading. There I learned to my chagrin that we recognize words from their word shape and that Modern psychologists call this image the Bouma shape.
This paper is written from the perspective of a reading psychologist. The data from dozens of experiments all come from peer reviewed journals where the experiments are well specified so that anyone could reproduce the experiment and expect to achieve the same result.
The goal of this paper is to review the history of why psychologists moved from a word shape model of word recognition to a letter recognition model, and to help others to come to the same conclusion. This paper will cover many topics in relatively few pages.
I will start by describing three major categories or word recognition models: the word shape model, and serial and parallel models of letter recognition. I will present representative data that was used as evidence to support each model. After all the evidence has been presented, I will evaluate the models in terms of their ability to support the data. And finally I will describe some recent developments in word recognition and a more detailed model that is currently popular among psychologists.