A Cognitive Approach to the Study of Language
Several researchers have hypothesized that in immediate memory and comprehension tasks, at least two main stages of perceptual processing occur. Figure 3.1 illustrates these stages. First, stimulus input enters a very temporary buffer store. During a low-level stage of processing, which I will call sensing, an image of the stimulus input is formed, based largely on physical features and patterns. This stage of processing is relatively passive and possibly parallel (i.e., more than one word might be processed at a time) (Aaronson, 1966; Shiffrin & Grantham, 1974; Wolford, 1975). The resultant image may be a direct representation, "much like that of a sound recording" (Pollack, 1959), or a mental photograph (Dick, 1974), and will decay rapidly while in this form. The sensed word is coded sufficiently to be used in certain monitoring, matching, or comparison tasks, but cannot survive the decay and interference in many recall or paraphrase tasks (Aaronson, 1968). Sensed representations are held in a relatively large capacity buffer store (Neisser's "echoic memory," Crowder and Morton's "precategorical acoustic store," Broadbent's "S-system") while waiting for higher-level linguistic encoding (Massaro, 1970a, 1970b, 1972). The higherlevel process, which I will call identifying, may code a word based on a meaning or verbal label (Pollack's and Crowder & Morton's "categorized" representations, Broadbent's "P-system"). Some psychologists question the inclusion of identification as a perceptual rather than a mnemonic process (Underwood, 1973). However, data to date do not even justify a clear dichotomy between these two levels. We are concerned here primarily with two stages of processing that increase the permanence and usability of the internal representation, whether they be perceptual or early mnemonic stages. After identification the decay rate of the words and their susceptibility to verbal interference is decreased, even though some of the initial sensory information was sacrificed in the lexical-semantic abstraction of properties that occurred in recoding. The higher-level identification process is "active" and at least partly serial [i.e., one word at a time (Broadbent, 1958; Neisser, 1967)]. A major function of this stage is to provide a structural organization for the string. The words are identified in a
particular order and sUbjective intonation grouping, which affect the seq uential organization during later retrieval (Aaronson, 1967).