Sentence formulation requires mapping pre-verbal messages onto linguistic structures. This message-to-language
mapping is often evaluated in eye-tracking tasks where speakers describe pictured events (The dog chased the mailman).
Speakers can begin sentence formulation by quickly selecting the first-fixated character as the sentential starting point
(lexical incrementality), or generating a rudimentary sentence plan based on their construal of the event gist before
selecting a starting point (hierarchical incrementality; Kuchinsky & Bock, 2010). Lexical incrementality predicts fast
divergence of fixations while hierarchical incrementality predicts slower divergence of fixations to the two characters
within 200ms of picture onset.