The authors investigated the idea that memory systems might have evolved to help us remember fitness-relevant information-specifically, information relevant to survival. In 4 incidental learning experiments, people were asked to rate common nouns for their survival relevance (e.g., in securing food, water, or protection from predators); in control conditions, the same words were rated for pleasantness, relevance to moving to a foreign land, or personal relevance. In surprise retention tests, participants consistently showed the best memory when words were rated for survival; the survival advantage held across recall, recognition, and for both within-subject and between-subjects designs. These findings suggest that memory systems are "tuned" to remember information that is processed for fitness, perhaps as a result of survival advantages accrued in the past.

A feature model of immediate memory is presented, and simulations are described. List items are characterized as multiattribute vectors that can be selectively overwritten by subsequent external events and by the ongoing stream of internal activity. Degraded primary memory vectors are compared with intact secondary memory vectors, and retrieval likelihood is computed as the ratio of similarities. The model is shown to account for the major modality-based phenomena of the immediate serial recall literature, including modality-based temporal grouping effects and the negative effects of phonological similarity. 251The ability to reconstruct recently presented information as it recedes backward in time is basic to a fully functioning cognitive system. The interpretation of spoken language, among other examples, requires the preservation of temporal order information, a task that is typically assumed to be a critical function of primary, or short-term, memory. This article describes a simulation model that handles a variety of phenomena characteristic of immediate retention. The model is based on an earlier descriptive framework (Nairne, 1988); its main appeal is to the composition of list traces in primary memory and to the manner in which trace composition might change as a function of interference from externally presented events and ongoing cognitive activities. The focus of the simulation studies is on modality-based effects in immediate memory. These effects are quite large and stable empirically, and their analysis exploits the feature-based properties of the model. In a later section, I apply the proposed mechanics to a range of other benchmark data in the immediate memory literature.Of the many variables that can affect performance in a task such as immediate serial recall, where subjects are required to reproduce short lists of items in the exact order of presentation, one of the more conspicuous is presentation modality. The modality effect refers to the superior recency performance that occurs for auditory, compared with visual, presentation. Typically, serial recall of auditory and visual lists leads to declining performance over serial position, but, for the last few serial positions, there is a relative auditory advantage (Conrad & Hull, 1968;Corballis, 1966;Craik, 1969;Murdock & Walker, 1969;Murray, 1966). The stimulus suffix effect is a related phenomenon, which is observed when an extra item, usually a word presented aloud, eliminates the modality effect by reducing the recency advantage that is found for auditory lists (Dallett, 1965).The presentation of list information aloud also interacts significantly with the organization of presentation: If a nine-item list is presented with the items in groups of three, separated by short pauses, auditory presentation leads to large grouping advantages, relative to visual presentation, and, within each group, there is a recency advantage for the last serial position (Frankish, 1985(Frankish, , 1989Ryan, 1969). In addition, under auditory presentation, increa...

No abstract

The effects of generation on the long-term retention of item and order information were examined in a between-list design in 3 experiments. In each experiment, completing word fragments during presentation significantly impaired long-term retention of serial order, as measured by either a reconstruction task or the amount of input-output correspondence in free recall. Memory for the individual items, however, was sometimes helped by generation. This pattern of dissociation, reminiscent of immediate memory findings, is used to interpret problematic issues in the generation effect literature and to argue for the role of the item-order distinction in the longterm-memory arena.

Psychologists often assume that short-term storage is synonymous with activation, a mnemonic property that keeps information in an immediately accessible form. Permanent knowledge is activated, as a result of on-line cognitive processing, and an activity trace is established "in" short-term (or working) memory. Activation is assumed to decay spontaneously with the passage of time, so a refreshing process-rehearsal-is needed to maintain availability. Most of the phenomena of immediate retention, such as capacity limitations and word length effects, are assumed to arise from trade-offs between rehearsal and decay. This "standard model" of how we remember over the short-term still enjoys considerable popularity, although recent research questions most of its main assumptions. In this chapter I review the recent research and identify the empirical and conceptual problems that plague traditional conceptions of short-term memory. Increasingly, researchers are recognizing that short-term retention is cue driven, much like long-term memory, and that neither rehearsal nor decay is likely to explain the particulars of short-term forgetting.