OBSERVATIONS Regularization in Short-Term Memory for Serial Order

Previous research has shown that short-term memory for serial order can be influenced by background knowledge concerning regularities of sequential structure. Specifically, it has been shown that recall is superior for sequences that fit well with familiar sequencing constraints. The authors report a corre-sponding effect pertaining to serial recall errors. Undergraduate participants performed immediate serial recall on sequences of pseudowords generated on the basis of an artificial grammar. After extensive experience with this material, recall errors displayed a bias toward regularizing responses, response sequences more probable, with respect to the artificial grammar, than the originally presented stimulus sequence. This regularization effect squares well with recent trace redintegration and Bayesian models of serial recall, and appears to represent an analog of the schema-based error patterns observed in other domains of memory. In a classic study of immediate serial recall, Baddeley, Conrad, and Hull (1965) demonstrated that consonant strings were better recalled when they contained high-frequency letter transitions than when they contained low-frequency transitions. This bigram fre-quency effect (later replicated by Kantowitz, Ornstein, & Schwartz, 1972; Mayzner & Schoenberg, 1964) provides one of numerous demonstrations that short-term memory for serial order can be influenced by background knowledge concerning domain-specific regularities in sequential structure. Even before Baddeley et al.’s (1965) study, Miller and Selfridge (1951) had observed better recall for sequences of words that contained high-frequency word transitions than for sequences containing low-frequency transi-tions. More recently, a number of studies have shown better recall for nonwords containing high-frequency, versus low-frequency, phoneme sequences (a phonotactic frequency effect; Gathercole