自变量 ■所呈现的记忆材料的性质( the nature of the material presented for memory ): It can be letters, digits, nonsense syllables, words phrases, sentences, paragraphs, or long passages of rose The characteristics of each of these types of material can also be varied:如词长、词频、词汇的具体/抽 象性等◼ 自变量 ◼ 所呈现的记忆材料的性质（the nature of the material presented for memory）： ◼ It can be letters, digits, nonsense syllables, words, phrases, sentences, paragraphs, or long passages of prose; ◼ The characteristics of each of these types of material can also be varied：如词长、词频、词汇的具体/抽 象性等