Strength models and serial position in short-term recognition memory

Abstract

A number of continuous strength models for memory are developed for and tested by an experimental study of recognition memory for three-digit numbers at all serial positions in lists of length two through seven. Empirical estimates of trace strength in different conditions, independent of response bias, are obtained by means of the operating characteristic. The principal theoretical findings are: (a) strength in short-term memory (STM) appears to decay exponentially with the number of subsequent items; (b) subjects report that they recognize an item if and only if strength in memory exceeds a criterion; (c) the first item of a list is remembered better than subsequent items because it receives a greater increment in strength in STM upon presentation, not because it decays more slowly in STM or because it acquires some strength in a long-term memory. © 1966.