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A framework for the conceptualization of a broad range of memory phenomena is proposed in this article. The framework integrates research on memory performance in young children, the elderly, and individuals under stress with research on memory performance in normal college students. One basic assumption of this viewpoint is that encoding operations vary in their attentional requirements. Operations that drain minimal energy from our limited-capacity attentional mechanism are called automatic; their occurrence does not interfere with other ongoing cognitive activity. Automatic operations function at a constant level under all circumstances. They occur without intention and do not benefit from practice. Certain automatic processes, we propose, are ones for which humans are genetically "prepared." These processes encode the fundamental aspects of the flow of information, namely, spatial, temporal, and frequency-of-occurrence information. These automatic processes are expected to show limited developmental trends. Other automatic processes develop through practice and function to prevent the subcomponents of complex skills from overloading our limited-capacity system. Contrasted with these processes are effortful operations such as rehearsal and elaborative mnemonic activities. They require considerable capacity and so interfere with other cognitive activities also requiring capacity. They are initiated intentionally and show benefits from practice.A second assumption of the present framework is that attentional capacity varies both within and among individuals. Depression, high arousal levels, and old age are among the variables thought to reduce attentional capacity. The conjunction of the two basic assumptions of the proposed framework yields the important prediction that the aged and individuals under stress will show a decrease in performance only on specific memory tasks, namely, on tasks requiring effortful processing.Evidence from the literature on development, aging, depression, arousal, and normal memory is presented in evaluation of the framework, and four experiments are described. The bulk of the available data is supportive of the framework. For instance, evidence indicates that frequency processing is not influenced by intention, practice, depression, or age. The article also includes discussion of the origins of this viewpoint in other attention and memory theories.

Two experiments assess adult age differences in the extent of inhibition or negative priming generated in a selective-attention task. Younger adults consistently demonstrated negative priming effects; they were slower to name a letter on a current trial that had served as a distractor on the previous trial relative to one that had not occurred on the previous trial. Whether or not inhibition dissipated when the response to stimulus interval was lengthened from 500 ms in Experiment 1 to 1,200 ms in Experiment 2 depended upon whether young subjects were aware of the patterns across trial types. Older adults did not show inhibition at either interval. The age effects are interpreted within the Hasher-Zacks (1988) framework, which proposes inhibition as a central mechanism determining the contents of working memory and consequently influencing a wide array of cognitive functions.

This chapter focuses on a set of attentional or executive control processes, all inhibitory, that operate in the service of an individual's goals to narrow and constrain the contents of consciousness to be goal relevant. An uncluttered or narrowly focused “working memory,” rather than a large one, is the ideal processing system. The narrow focus maximizes the speed and accuracy of on-line processing because it reduces the likelihood of switching attention to goal-irrelevant representations. The work is similar to that of other investigations in its focus on executive processes as a critical source of working memory variation as well as variation in many cognitive domains. The emphasis on inhibitory processes may be the characteristic that most differentiates their work from others.

The term automaticity is in widespread use in current empirical and theoretical work in cognition. There is, however, no standard definition of the term (e.g., Hirst, 1982b, Shiffrin, Dumais, & Schneider, 1981. Our definition (Hasher & Zacks, 1979) is used here.

Younger and older adults were compared in 4 directed forgetting experiments. These varied in the use of categorized versus unrelated word lists and in the use of item by item versus blocked remember-forget cueing procedures. Consistent with L. Hasher and R. T. Zacks's (1988) hypothesis of impaired inhibitory mechanisms in older adults, a variety of findings indicated that this age group is less able than yoimger adults to suppress the processing and retrieval of items designated as to be forgotten (TBF). Specifically, in comparison with younger adults, older adults produced more TBF word intrusions on an immediate recall test (Experiments 1A and 1B), took longer to reject TBF items (relative to a neutral baseline) on an immediate recognition test (Experiment 3), and recalled (Experiments 1A, 1B, and 2) and recognized (Experiments 1B and 2) relatively more TBF items on delayed retention tests in which all studied items were designated as targets.In this article, we present four experiments comparing the performance of younger and older adults on directed forgetting tasks. In this type of task (e.g., see Bjork, 1989), participants are presented items to study, some of which they are told to remember and others of which they are told to forget. Because the cueing as to which items are to be remembered (TBR items) and which are to be forgotten (TBF items) occurs after the items have been presented for study, participants must pay some attention to each item as it is presented. Thus, the directed forgetting paradigm investigates the ability to forget some inputs that one has recently attended to while at the same time remembering others presented in the same context and near the same time. To the degree that one is successful at this task, as younger adults generally are, the following trends are seen: The presence of TBF items on a list does not reduce recall or recognition of TBR items; there are few intrusions of TBF items when participants are asked to report only TBR items; and performance on TBF items is relatively poor when, on a later retention test, participants are asked to report TBF as well as TBR items.

Older and younger adults read aloud and answered questions about texts that did or did not have distracting material interspersed amid target text. When present, distracting material occurred in a different type font from that of target material. Across 2 experiments, distracting material was meaningless, meaningful but unrelated to the text, or meaningful and text related. Subjects were instructed to attend only to the target text. Reading time measures indicated that compared with younger adults, older adults have a more difficult time ignoring the distracting information, particularly information meaningfully related to target text. Verbal ability differences among older, but not younger, adults moderated distraction effects. Age differences in inhibitory attentional mechanisms were considered as processes influencing distraction effects.

A major view in cognitive psychology presumes the existence of limits on mental capacity, limits that vary with circumstances and task demands and that largely determine the performance of individuals (see, e.g., Kahneman, 1973). The Daneman and Carpenter (1980) measure of working memory (and its many variants; see, e.g., Engle, Cantor, & Carulo, 1992;Friedman & Miyake, 2004) is thought to give a snapshot of capacity by assessing an individual's ability to actively maintain important information while also engaging in some form of ongoing processing. From a capacity viewpoint, the bigger the mental desk space, the better performance should be on a wide range of tasks, including reading comprehension and reasoning. On the assumption that older adults have reduced working memory capacity, age differences might be explained.However, a study on reading comprehension and memory had findings that were uninterpretable from this perspective (Hamm & Hasher, 1992). Older adults showed comprehension of stories that equaled that of young adults but did so by keeping more, not less, information in mind as they read. These capacity-challenging findings were critical to the development of an alternative view of cognition and of age (and individual) differences in cognition (Hasher & Zacks, 1988). Two simple hypotheses were advanced: (a) that activation in response to familiar cues and thoughts is largely automatic, as is its spread through a network, and (b) that activation requires down-regulation for goals to be accomplished. Activation was presumed to be equivalent across people and circumstances. Down-regulation was presumed to require inhibition and also to differ among individuals and across groups and circumstances to account for performance in a wide range of tasks.Thanks go to Amanda K. Govenar and David Bissig for their help in organizing the material for this chapter. Support for this project came from National Institute on Aging Grant R37 AG04306.