Previous research has provided evidence that semantic information significantly influences processing in short-term memory (Jensen, 1987; Shulman, 1970, 1972). This study examined semantically related and associated interference effects in identity probe recognition tasks with undergraduates, older subjects, and brain-damaged patients. Associative interference effects were presumed to result from automatic spreading activation in a word recognition system, and were expected to produce interactions with serial position. No interactions between interference effects and serial position were obtained. Modality of presentation had an influence on the size of the interference effects obtained, with auditory presentation decreasing the interference effect size. These results were interpreted as evidence that interference effects in probe recognition tasks are the result of a process of attribute or feature comparison (Anisfeld and Knapp, 1968). Results from the patient experiments were equivocal and suggest that the probe recognition task is not appropriate for use with brain-damaged patients.

This study explored whether faces are perceived differently than other visual stimuli. Using the speeded-classification task, evidence of holistic processing was found for faces with normal organization but not for the same stimuli when the eyes, nose, and lips were not in their ordinary positions. Sets of interior features (eyebrows, eyes, nose, and lips) were subsequently tested for holistic processing. No evidence for holistic processing was found between eyebrow/eye and nose/lips groups or between the nose and the lips. However, it was found that decisions on the eyebrows could be made independently of the eyes but that decisions on the eyes could not be made independently of the eyebrows. This asymmetric-separable relationship persisted when the eyes and eyebrows were presented by themselves or in the context of a face, when they were presented upright or inverted, and when either a single eye/eyebrow or both eyes/eyebrows were presented. Decisions on inverted eyes were more difficult than decisions on upright eyes. No evidence of holistic processing was found for an eye/eyebrow presented in the context of non-facial stimuli. These results suggest that the asymmetric-separable relationship between the eyes and the eyebrows plays a role in the unique characteristics associated with the perception of faces.

Eight experiments were conducted to investigate the phenomenon of spontaneous recovery, or memory improvement over time without repeated testing. While this phenomenon has been previously studied within the verbal learning tradition, evidence for its existence has been inconclusive. Experiments 1a through 5 demonstrated the reliability of the effect. The procedure was gradually modified throughout these experiments, leading to the following conclusions. First, retroactive interference (which is a necessary condition for recovery) is maximized when subjects are led to believe that their knowledge of the target list will interfere with interpolated learning. Also, assessing spontaneous recovery in a within-, rather than a between-subjects paradigm, is a more powerful approach, and allows for a more sensitive test of the phenomenon. Most importantly, spontaneous recovery was reliably produced. The proposed explanation for the phenomenon involves retrieval inhibition, and its subsequent dissipation, as the processes underlying recovery. More specifically, inhibition prevents subjects from generating target items on immediate tests. As the inhibition dissipates, more items can be recalled on later tests; this occurs despite the presumption that normal forgetting is also operating upon the target list. Experiment 6 attempted to extend spontaneous recovery to an implicit, word-stem completion test. Following study conditions roughly similar to those used in the prior experiments, there was no evidence for either retroactive interference or spontaneous recovery on the implicit test. This demonstrates, at the very least, a study manipulation that dissociates explicit free recall with implicit word-stem completion. More interestingly, it suggests that retrieval inhibition might only operate upon intentional uses of retrieval, although more data would be required to confirm this hypothesis. Experiment 7 applied the spontaneous recovery paradigm to directed forgetting. If subjects are using retrieval inhibition to "block out" to-be-forgotten items, then these items should recover over time. Results provide limited evidence for this conclusion. Retrieval inhibition, and its subsequent dissipation, are hypothesized to be the primary processes underlying directed forgetting.

Four experiments are presented which explore consumer preferences for more detailed, or explicit warning information and the effects of such information on anticipated purchases of products. In Experiments 1 and 2, explicit and nonexplicit warning labels were presented for several common consumer products. Results of these studies indicate that products displaying nonexplicit warnings were preferred to those containing explicit warnings. However, this trend was reversed for one product, and for many products the detail with which a warning described potential consequences had little effect on anticipated purchase decisions. An attempt was made in Experiments 3 and 4 to minimize precursors to hazardousness judgements (e.g., familiarity or experience) by using fictitious products. Results of these latter two experiments indicate that regardless of the perceived benefits of an unfamiliar product or the severity, likelihood and controllability of its injuries, an overwhelming buying preference existed for explicit warnings as well as a need to provide more detailed consequence information in the warnings of such products. Overall these findings suggest that the level of detail with which a warning describes potentially harmful consequences of using a product does influence anticipated purchases when uncertainty exists about product-related danger.

A series of experiments explores the role of willful control over the learning of complex, rule-governed systems such as language. Willful control is operationalized as the enhancement of learning by the deliberate application of cognitive strategies. Subjects studied strings of symbols generated according to the rules of a system known as an artificial grammar. They were then tested on their knowledge of the grammar's rules. In some conditions, symbols drawn from the vocabulary used in the grammar were inserted into each string, rendering the string somewhat ungrammatical. In the informed condition, the inserted symbols were identified; in the uninformed condition, the inserted symbols were not identified. If subjects were able to exert willful control by ignoring the inserted symbols, performance in the informed condition should exceed performance in the uninformed condition. If they were not able to exert willful control, there should no difference between the informed and uninformed conditions. Evidence that the subjects had at least some degree of willful control was obtained in each of 10 experiments. Experiments 1, 2, 3, and 4 included a condition in which the subjects saw strings with no inserted symbols. Performance in this condition was consistently superior to performance in the informed condition, implying that the extent of willful control was less than complete. Experiments 5, 6, 7, and 8 tested the hypothesis that the extent of willful control would depend on the number of symbols inserted. Experiment 9 tested the hypothesis that exposure to strings with no ungrammatical symbols would enhance subjects' ability to ignore such symbols in subsequent strings. Finally, Experiment 10 tested the hypothesis that willful control would be increased if the inserted symbols did not come from the same vocabulary as the grammar. None of these hypotheses was supported. The general conclusion from these experiments is that subjects can exert some degree of willful control over the learning of complex systems, but the extent of that control is substantially limited.

Three experiments investigated the ways memories change over repeated tests. A tradition of previous work started by Ballard (1913) revealed net improvement (or hypermnesia) over tests, while Bartlett (1932) showed intertest forgetting. Differences between the paradigms include the type of material learned (lists of items vs. prose) and the delay interval between recall tests (several days for Bartlett and up to one day for Ballard). Both factors were examined in three experiments. In all experiments, hypermnesia was obtained across repeated memory tests when tests occurred within a single, experimental session. However, intertest forgetting resulted after a one-week delay, replicating Bartlett. Performance on repeated tests was discovered to be a function of the number of prior tests and the delay between tests, while response criterion (lenient or strict) and the nature of the learned material (pictures or prose passages) were not important.

Research has shown that generating words in a study phase (e.g. "shoe" from foot-s$\sb{--}$e) usually yields better memory performance compared to reading words (e.g. foot-shoe), and this advantage for generated words relative to read words is called the generation effect. One particularly interesting version of the generation effect was studied by Jacoby (1978). In two conditions of his study, subjects generated a word once (e.g. foot-s$\sb{--}$e) or generated a word immediately after reading it (e.g. foot-s$\sb{--}$e preceded by foot-shoe). Jacoby (1978) found that generating a word once produced better cued recall (e.g. foot-? ? ? ?) than reading a word, then generating it. One purpose of the present experiments was to investigate if Jacoby's (1978) results would generalize to other memory tests. The experiments reported manipulated the number of study presentations, the modality of study presentation, the difficulty of generating a word, and the match between perceptual cues (e.g. s$\sb{--}$e) presented at study and test, and examined performance on four tests (associative cued recall, recognition, word fragment cued recall, and word fragment completion). Jacoby's (1978) results were replicated for associative cued recall, but other patterns of data were obtained on the other tests. A new finding for a word fragment cued recall test occurred based on the match of perceptual cues between study and test. Presenting the same word fragment (e.g. s$\sb{--}$e) at study and test resulted in better memory performance than did presenting different word fragments at study and test cue (e.g. s${--}$e at study but s$\sb-$o$\sb-$ at test). Dissociations between word fragment cued recall and the word fragment completion ruled out the possibility that generation effects obtained for the word fragment completion test were due to subjects using intentional retrieval strategies. Most of the results were explainable with the transfer appropriate processing framework, which states that the greater the overlap in mental processes engaged at study and test, the better test performance will be.

Modern automotive instrument panels are often equipped with numeric readout and digital bargraph displays instead of traditional analog displays. An informal survey of 1990 model cars revealed wide disparity in automotive displays. Three major classes of displays were in use: (1) traditional analog, (2) binary indicators, and (3) readout displays. The present work reports results from four experiments of display monitorability. Twelve computer-simulated displays were designed for evaluation by dual-task methodology. Subjects were required to maintain performance on a demanding tracking task while monitoring configurations of four-displays for "critical readings." Subjects' latencies to respond to such readings and their tracking error scores were collected. Experiment 1 examined displays in homogeneous clusters. Orientation, configuration and class were studied. Experiment 2 compared displays in heterogeneous configurations. Experiment 3 studied the addition of color to the displays to facilitate the detection of a critical reading. Static color (i.e., a "red zone") was added to the analog displays while dynamic color was added to the bargraph displays. Finally, Experiment 4 examined the effect of check-readable layouts for analog and bargraph displays. Older subjects were slower to respond to all displays and exhibited poorer tracking performance. They also had more variability than younger subjects on both of these measures. This result was likely due to age-related slowing rather than changes in cognitive processes. No class of displays studied emerged as superior, but the binary indicator (a modified warning lamp) generated the fastest responses. Although no evidence was found for effects of orientation, configuration or check-readability, support was found for color facilitation. Male subjects tended to respond faster when static color was present, and age-related facilitation was found for dynamic color. The addition of dynamic color to displays monitored by subjects in the middle and older age groups approximately compensated for age-related RT decrements. It is likely that displays which incorporate dynamic color elements will be most useful for presenting rate information as well as calling attention to off-normal readings. Pending further study, it is recommended that designers use new display technology with caution.

An exploratory study was conducted with users of a command-based system, MS-DOS, and the Graphical User Interfaces (GUI) of the Apple Macintosh. It was hypothesized that command-based interfaces and GUIs differ in the ease with which they afford attainment of particular concepts, and that in general the concepts investigated would be more readily attained by Macintosh users. The study attempted to assay subjects' knowledge of particular computer-related concepts, their ability to perform related operations, and the organization of that knowledge. Contrary to some theory (e.g., Tennyson and Cocchiarelli, 1986), a double dissociation between verbalizable conceptual knowledge and performance was observed. Results of the study suggested differences in the support provided by DOS and the Macintosh interface for development of knowledge of particular concepts and procedures, underscoring the potential value of understanding the detailed effects of particular interfaces, and classes of interface, upon user knowledge.

The prior presentation of a word enhances the probability that the word will be identified from a degraded cue. This enhancement, or priming, may occur without recollection of the prior presentation. In investigations of the effect of delay on nonrecollective memory, priming of word completion may occur at long delays after the initial word presentation (e.g., HORIZON) when the degraded cue contains scattered letters (e.g., R Z) but not when the degraded cue contains the initial letters (e.g., HOR$\underline{\qquad}).$ These particular cues are known as fragments and stems respectively. Priming of fragment completion may occur weeks after the study presentation whereas priming of stem completion may disappear within hours. The present research investigated this apparent discrepancy between the duration of priming effect for the two types of cues by examining completion of both within the same experiment. Particularly, it tested the hypothesis that the decline in priming of completion is greater when cues have many possible completions. Subjects completed fragments that have 1 completion or fragments and stems that have more than 7 completions. Priming was measured over a 48-hour delay interval in each of 4 experiments. Priming of stem completion declined at a greater rate than priming of fragment completion over the 48-hour interval, thus replicating within a single experiment the previous between-experiment findings. The number-of-completions hypothesis was not rejected in Experiments 1 and 3 because the decline in priming of multiple fragment completion did not differ from the decline in priming of stem or unique fragment completion. However, in Experiment 2 the decline in priming of multiple fragment completion differed from the decline in priming of stem completion but not from the decline in priming of unique fragment completion. Thus, the number-of-completions hypothesis may not be a viable explanation of the differential effect of delay on priming of fragment and stem completion. When the same words served in both the unique fragment and stem conditions, the effect of delay on priming of completion was similar for both conditions (Experiment 4).