Abstract: The present research is to explore whether there is sentence-type ef-fect in immediate and long-term memory. Three types of sentences werechosen: declarative, interogative and passive, each sentence consisted ofseven Chinese characters. Three experiments were conducted: two on STMtasks. One on LTM tasks. The STM experiments showed that the threesentence-types were stored and retrieved in STM, they possess approxi-mately equal amounts of short-term acquisition and occupied approxima-tely equal space within STM capacity. It can be seen that informationof short-term storage is not affected by sentence-type. However, differ-ent sentence-types have quite different effect in the amount of long-termretention and forgetting rate. The declarative sentences were betterstored in LTM than passive and interrogative sentences. Besides, therewas a strong tendency of replacing non-kernel (intrrogative and passive)sentences by kernel (declarative or active) sentences in LTM. These res-ults showed that once sentence information is transfered into LTM, thesentence-type information seems to be lost, the encoded and retentedinformation is the meanings of sentences. Proposition is the unit of the mean-ing. The propositions take tendentiously the simplest and clearest form,that is, declarative or active sentence-types. A counter-transformation orreduction hypothesis is proposed to explain the advantage of declarative(or active) sentence.

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