Garden path effect

A garden path sentence, such as "The old man the boat" (meaning "Old people are the crew of the boat"), is a grammatically correct sentence that starts in such a way that a reader's most likely interpretation will be incorrect; the reader is lured into a parse that turns out to be a dead end or yields a clearly unintended meaning. "Garden path" refers to the saying "", meaning to be deceived, tricked, or seduced.

Such a sentence leads the reader toward a seemingly familiar meaning that is actually not the one intended. It is a special type of sentence that creates a momentarily ambiguous interpretation because it contains a word or phrase that can be interpreted in multiple ways, causing the reader to begin to believe that a phrase will mean one thing when in reality it means something else. When read, the sentence seems ungrammatical, makes almost no sense, and often requires rereading so that its meaning may be fully understood after careful parsing.

When reading a sentence, readers will analyze the words and phrases they see and make inferences about the sentence’s grammatical structure and meaning in a process called parsing. Generally, readers will parse the sentence chunks at a time and will try to interpret the meaning of the sentence at each interval. As readers are given more information they make an assumption of the contents and meaning of the whole sentence. With each new portion of the sentence encountered, they will try to make that part make sense with the sentence structures that they have already interpreted and their assumption about the rest of the sentence. The garden path sentence effect occurs when the sentence has a phrase or word with an ambiguous meaning that the reader interprets in a certain way, and when they read the whole sentence there is a difference in what has been read and what was expected. The reader must then read and evaluate the sentence again to understand its meaning. The sentence may be parsed and interpreted in different ways due to the influence of pragmatics, semantics, or other factors describing the extralinguistic context.

Various strategies can be used when parsing a sentence, and there is much debate over which parsing strategy humans use. Differences in parsing strategies can be seen from the effects of a reader attempting to parse a part of a sentence that is ambiguous in its syntax or meaning. For this reason, garden path sentences are often studied as a way to test which strategy humans use. Two debated parsing strategies that humans are thought to use are serial and parallel parsing.

Serial parsing means that the reader makes one interpretation of the ambiguity, and continues to parse the sentence in the context of the interpretation. The reader will continue to use their initial interpretation as reference for future parsing until disambiguating information is given.

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