Garden path sentences are used in psycholinguistics to illustrate that human beings process language one word at a time.

The classic example is:

"The horse raced past the barn fell."

The reader usually starts to parse this as an ordinary active instransitive 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 food eaten on the train was good."

Natural language parsing

The Garden Path effect presents a challenge for computational linguistics, because parsers typically require whole sentences or clauses to analyse. The incremental processing that humans demonstrate could require some changes in the parsers and/or the grammars they use. On the other hand, this effect could also provide hints about how to cope with natural language ambiguity.

Other examples