the activation-verification model (avm) is another model that was developed to account for reaction time data from lexical decision and naming tasks. the basic operations explored in the avm that are involved in word and letter recognition are encoding, verification, and decision. both the iam and the avm share many basic assumptions such as the fact that stimulus input activates spatially-specific letter units, that activated letter units, modulate the activity of word units, and that letter and word recognition are frequently affected by top-down processes (e.g. reading the phrase "a cow says..." a person would guess "moo" and in checking that the word begins with 'm' ignores the rest of the letters).