Memory for sentences and noun phrases of extreme depth

Memory for orally presented noun phrases and sentences was investigated in two experiments. Syntactic depth (D) of the phrases and sentences was varied with D approaching the values of 7 ± 2. Consistent with recent investigations, these studies found D not to be generally related to recall of sentences, phrases, or individual words within sentences. However, recall of individual words from an adverbial noun phrase apparently was related to D. The apparent relationship is accounted for not by depth of individual words, but in terms primarily of superior noun retention and its interaction with serial position effects. In addition, conditional recall probabilities for another type of phrase, a noun phrase with prenominal adjectives, indicate stronger relationships between adjectives and the noun than between successive adjectives. It is concluded that the Yngve grammar is deficient as a psycholinguistic model.