Feature units, letter units

From MerrimackWiki

Definition

.In the interactive activation model proposed by McClelland and Rumelhart, there are three levels of activation in letter recognition: the feature level containing feature units, the letter level containing letter units, and the word level containg word units (or all the words a person knows). Feature units are the straight (vertical, horizontal, and slanted) and curved lines that can be combined in various ways to form letters. Letter units represent each individual letter of the alphabet. In the complete model there are 12 feature units and 26 letter units.

Significance

.Feature and letter units are mental representations that help us to recognize 1.single letters, 2.single words and 3.letters within a word. ie. Feature units for the letter "K" such as a vertical line and 2 slanted lines are activated when the letter "k" is presented. Both classifications of units are part of a belief that our brain uses a system of orientated lines to identify objects such as letters and words. Although each letter and word may appear different, they may have a number of similarities which would explain some of the confusion people have in identifying them. Using the concept of orientated lines helps to reveal some of these similarities we may not have otherwise seen.