Garden path sentences are used in psycholinguistics to illustrate that human beings process language one word at a time. The name comes from the saying "to be led down the garden path" meaning "to be misled". The classic example is:

"The horse raced past the barn fell."

The reader usually starts to parse this as an ordinary active intransitive sentence, but stumbles upon reaching the word "fell." At this point, the reader is forced to backtrack and look for other structures. It may take some rereading and/or relistening to realize that "raced past the barn" is in fact a reduced relative clause with a passive participle, implying that someone other than the horse raced the horse and that "fell" is the main verb. The correct reading is then:

"The horse (that was raced past the barn [by someone that is not the horse itself]) fell."

This example hinges on the ambiguity of the lexical category of the word "raced": it can be either a past-tense verb or a passive participle. Note that there is no ambiguity for some other verbs, even when the sentence structure is similar:

"The car driven past the barn crashed."

Natural language parsing

The Garden Path effect provides a psycholinguistic motivation for the incremental processing of natural language. This presents a challenge for computational linguistics as current parsers typically require whole sentences or clauses to analyse. Enhancing natural language parsers so that they perform incremental processing might require fundamental changes in the parsing strategy and/or the grammars they use. The enhancements in questions are not a matter of deliberately introducing garden path errors into natural language systems, but giving these systems the ability to process language incrementally, autonomously without user intervention to tell systems where individual sentences begin and end. Furthermore, incremental processing might allow systems to deal more robustly with linguistic phenomena such as repair and interruption. The ability to simulate the garden path effect is not computational linguistic goal in itself, but a potentially useful measure of the ability to perform incremental processing.

Other examples

• "While Philip was washing the dishes crashed on the floor."
• "The man who hunts ducks out on weekends."
• "The cotton clothing is usually made of grows in Mississippi."
• "Fat people eat accumulates."
• "The complex houses married and single students and their families."
• "The prime number few."
• "The old man the boat".
• "The tycoon sold the offshore oil tracts for a lot of money wanted to kill JR."
• "I convinced her children are noisy."
• "The player kicked the ball kicked the ball."
• "Whose broad stripes and bright stars, through the perilous fight, O'er the ramparts we watched, were so gallantly streaming?"