Showing papers in "Journal of Experimental Psychology: Learning, Memory and Cognition in 2002"

Access to information in working memory: exploring the focus of attention.

Abstract: Participants memorized briefly presented sets of digits, a subset of which had to be accessed as input for arithmetic tasks (the active set), whereas another subset had to be remembered independently of the concurrent task (the passive set). Latencies for arithmetic operations were a function of the setsize of active but not passive sets. Object-switch costs were observed when successive operations were applied to different digits within an active set. Participants took 2 s to encode a passive set so that it did not affect processing latencies (Experiment 2). The results support a model distinguishing 3 states of representations in working memory: the activated part of long-term memory, a capacity limited region of direct access, and a focus of attention.

Statistical learning of higher-order temporal structure from visual shape sequences.

Abstract: In 3 experiments, the authors investigated the ability of observers to extract the probabilities of successive shape co-occurrences during passive viewing. Participants became sensitive to several temporal-order statistics, both rapidly and with no overt task or explicit instructions. Sequences of shapes presented during familiarization were distinguished from novel sequences of familiar shapes, as well as from shape sequences that were seen during familiarization but less frequently than other shape sequences, demonstrating at least the extraction of joint probabilities of 2 consecutive shapes. When joint probabilities did not differ, another higher-order statistic (conditional probability) was automatically computed, thereby allowing participants to predict the temporal order of shapes. Results of a single-shape test documented that lower-order statistics were retained during the extraction of higher-order statistics. These results suggest that observers automatically extract multiple statistics of temporal events that are suitable for efficient associative learning of new temporal features. Our visual experience consists almost entirely of spatiotemporal events created by observer movement through the visual array (through eye, head, and body movements) and/or by independent movements of objects with respect to the static environment. Therefore, the computational task facing the visual system during the interpretation or learning of new visual scenes is one of extracting spatiotemporal correlations. A simple classification of these spatiotemporal correlations is illustrated in Figure 1, in which low-level visual analyzers respond to the presence of one or more object features in two or more time frames. Several different types of spatiotemporal correlations could be present across multiple time frames: (a) no change in the features or the position of the object, (b) a change in object position, with no change in the features of the object, (c) a smooth transformation of one or more features, with no change in position, or (d) an abrupt change in one or more features of the object, with or without a change in position. Type A is a prototypical example of static vision, in which high spatial correlations among a set of features are present for extended periods of time. Type B is an example of object motion (short- or long-range, depending on the magnitude of the change in position across frames). Type C is an example of object rotation (in either 2-D or 3-D) or object deformation. And Type D is an example of a sudden replacement of one object with a new object, or a saccade to a new target.

Intrinsic frames of reference in spatial memory

Abstract: Three experiments investigated the frames of reference used in memory to represent the spatial structure of the environment. Participants learned the locations of objects in a room according to an intrinsic axis of the configuration; the axis was different from or the same as their viewing perspective. Judgments of relative direction using memory were most accurate for imagined headings parallel to the intrinsic axis, even when it differed from the viewing perspective, and there was no cost to learning the layout according to a nonegocentric axis. When the shape of the layout was bilaterally symmetric relative to the intrinsic axis of learning, novel headings orthogonal to that axis were retrieved more accurately than were other novel headings. These results indicate that spatial memories are defined with respect to intrinsic frames of reference, which are selected on the basis of egocentric experience and environmental cues.

A contextual change account of the directed forgetting effect.

Abstract: The authors propose that the costs and benefits of directed forgetting in the list method result from an internal context change that occurs between the presentations of 2 lists in response to a “forget” instruction. In Experiment 1 of this study, costs and benefits akin to those found in directed forgetting were obtained in the absence of a forget instruction by a direct manipulation of cognitive context change. Experiment 2 of this study replicated those findings using a different cognitive context manipulation and investigated the effects of context reinstatement at the time of recall. Context reinstatement reduced the memorial costs and benefits of context change in the condition where context had been manipulated and in the standard forget condition. The results are consistent with a context change account of directed forgetting. Directed forgetting is a phenomenon first studied by R. A. Bjork, LaBerge, and LeGrand (1968) whereby people appear to be able to intentionally forget information, making it less accessible to later attempts at recall and reducing interference from that information. The paradigm involves two variations: the item method, which seems to reflect differential encoding of items, and the list method, which does not depend on differential encoding of items (Basden, Basden, & Gargano, 1993). The present work concerns the mechanism of directed forgetting with the list method. Participants are presented two lists of items to study but, immediately after List 1, half of the participants are instructed to forget List 1 (the “forget” group), whereas the remaining half are told to continue remembering List 1 (the “remember” group). The final test requires recall of both lists. Typically, the forget group recalls fewer items from the first list than does the remember group—a finding referred to as the costs of directed forgetting

The influence of phonological similarity neighborhoods on speech production.

Abstract: The influence of phonological similarity neighborhoods on the speed and accuracy of speech production was investigated with speech-error elicitation and picture-naming tasks. The results from 2 speech-error elicitation techniques-the spoonerisms of laboratory induced predisposition technique (B. J. Baars, 1992; B. J. Baars & M. T. Motley, 1974; M. T. Motley & B. J. Baars, 1976) and tongue twisters-showed that more errors were elicited for words with few similar sounding words (i.e., a sparse neighborhood) than for words with many similar sounding words (i.e., a dense neighborhood). The results from 3 picture-naming tasks showed that words with sparse neighborhoods were also named more slowly than words with dense neighborhoods. These findings demonstrate that multiple word forms are activated simultaneously and influence the speed and accuracy of speech production. The implications of these findings for current models of speech production are discussed.

The contributions of color to recognition memory for natural scenes

Abstract: The authors used a recognition memory paradigm to assess the influence of color information on visual memory for images of natural scenes. Subjects performed 5%-10% better for colored than for black-and-white images independent of exposure duration. Experiment 2 indicated little influence of contrast once the images were suprathreshold, and Experiment 3 revealed that performance worsened when images were presented in color and tested in black and white, or vice versa, leading to the conclusion that the surface property color is part of the memory representation. Experiments 4 and 5 exclude the possibility that the superior recognition memory for colored images results solely from attentional factors or saliency. Finally, the recognition memory advantage disappears for falsely colored images of natural scenes: The improvement in recognition memory depends on the color congruence of presented images with learned knowledge about the color gamut found within natural scenes. The results can be accounted for within a multiple memory systems framework.

Evidence for a cascade model of lexical access in speech production

Abstract: How word production unfolds remains controversial. Serial models posit that phonological encoding begins only after lexical node selection, whereas cascade models hold that it can occur before selection. Both models were evaluated by testing whether unselected lexical nodes influence phonological encoding in the picture-picture interference paradigm. English speakers were shown pairs of superimposed pictures and were instructed to name one picture and ignore another. Naming was faster when target pictures were paired with phonologically related (bed-bell) than with unrelated (bed-pin) distractors. This suggests that the unspoken distractors exerted a phonological influence on production. This finding is inconsistent with serial models but in line with cascade ones. The facilitation effect was not replicated in Italian with the same pictures, supporting the view that the effect found in English was caused by the phonological properties of the stimuli.

When debiasing backfires: accessible content and accessibility experiences in debiasing hindsight.

Abstract: Two studies demonstrated that attempts to debias hindsight by thinking about alternative outcomes may backfire and traced this to the influence of subjective accessibility experiences. Participants listed either few (2) or many (10) thoughts about how an event might have turned out otherwise. Listing many counterfactual thoughts was experienced as difficult and consistently increased the hindsight bias, presumably because the experienced difficulty suggested that there were not many ways in which the event might have turned out otherwise. No significant hindsight effects were obtained when participants listed only a few counterfactual thoughts, a task subjectively experienced as easy. The interplay of accessible content and subjective accessibility experiences in the hindsight bias is discussed.

Central bottleneck influences on the processing stages of word production.

Abstract: Does producing a word slow performance of a concurrent, unrelated task? In 2 experiments, 108 participants named pictures and discriminated tones. In Experiment 1, pictures were named after cloze sentences; the durations of the word-production stages of lemma and phonological word-form selection were manipulated with high- and low-constraint cloze sentences and high- and low-frequency-name pictures, respectively. In Experiment 2, pictures were presented with simultaneous distractor words; the durations of lemma and phoneme selection were manipulated with conceptually and phonologically related distractors. All manipulations, except the phoneme-selection manipulation, delayed tonediscrimination responses as much as picture-naming responses. These results suggest that early wordproduction stages—lemma and phonological word-form selection—are subject to a central processing bottleneck, whereas the later stage—phoneme selection—is not. A fundamental issue in psychology concerns how easily we can do more than one thing at the same time. Not only is this issue of practical significance (e.g., is it scientifically justifiable to prohibit talking on cellular phones while driving?), but it is also of scientific interest. Specifically, the extent that a task can be performed without hindering other simultaneously performed tasks implies that the task is carried out by separate, dedicated processing mechanisms. In contrast, if performance of one task interferes with performance of another, that interference implies that at least some components of that task are carried out by shared processing mechanisms. One set of abilities that seems especially likely to be based on dedicated processing mechanisms is our linguistic abilities. Linguistic processes may be highly specialized, as they may be based on a substrate that is cognitively, anatomically, and genetically distinct from that of other, nonlinguistic processes (e.g., Pinker, 1994). Furthermore, language performance is highly practiced, and practice may lead linguistic processing mechanisms to operate automatically (e.g., Cohen, Dunbar, & McClelland, 1990). The dedicated mechanisms that might underlie the performance of a single kind of task are here termed modular processing mechanisms.

Exemplar and prototype models revisited: response strategies, selective attention, and stimulus generalization.

Abstract: J. D. Smith and colleagues (J. P. Minda & J. D. Smith, 2001; J. D. Smith & J. P. Minda, 1998, 2000; J. D. Smith, M. J. Murray, & J. P. Minda, 1997) presented evidence that they claimed challenged the predictions of exemplar models and that supported prototype models. In the authors’ view, this evidence confounded the issue of the nature of the category representation with the type of response rule (probabilistic vs. deterministic) that was used. Also, their designs did not test whether the prototype models correctly predicted generalization performance. The present work demonstrates that an exemplar model that includes a response-scaling mechanism provides a natural account of all of Smith et al.’s experimental results. Furthermore, the exemplar model predicts classification performance better than the prototype models when novel transfer stimuli are included in the experimental designs. A classic issue in cognitive psychology concerns the manner in which people represent categories in memory. According to prototype models (Homa, 1984; Posner & Keele, 1968; Reed, 1972), people represent categories by forming a summary representation that is a central tendency of all of the experienced members of a category. Classification decisions are based on the similarity of an item to the alternative prototypes. By contrast, according to exemplar models (Hintzman, 1986; Medin & Schaffer, 1978; Nosofsky, 1986), people represent categories by storing the individual members or exemplars of a category as separate traces and classify items based on their similarity to these stored exemplars.

What exactly interacts with spelling-sound consistency in word naming?

Abstract: Word frequency, age of acquisition (AoA), and imageability were combined with spelling-sound consistency, and their effects on word naming were examined Frequency and AoA interacted with consistency (Experiments 1 and 2) Imageability did not (Experiment 3) Experiment 4 replicated Experiment 2 of E Strain, K E Patterson, and M S Seidenberg's (1995) study and obtained the same apparent effect of imageability on naming That effect disappeared when AoA was entered as a covariate An explanation of the interactions of consistency with frequency and AoA is offered in terms of the properties of adaptive connectionist networks given gradual and cumulative training

Orientation specificity and spatial updating of memories for layouts.

Abstract: This article examines the degree to which knowledge about the body's orientation affects transformations in spatial memory and whether memories are accessed with a preferred orientation. Participants learned large paths from a single viewpoint and were later asked to make judgments of relative directions from imagined positions on the path. Experiments 1 and 2 contribute to the emerging consensus that memories for large layouts are orientation specific, suggesting that prior findings to the contrary may not have fully accounted for latencies. Experiments 2 and 3 show that knowledge of one's orientation can create a preferred direction in spatial memory that is different from the learned orientation. Results further suggest that spatial updating may not be as automatic as previously thought.

Spatial updating of locations specified by 3-d sound and spatial language.

Abstract: Blind and blindfolded sighted observers were presented with auditory stimuli specifying target locations. The stimulus was either sound from a loudspeaker or spatial language (e.g., "2 o'clock, 16 ft"). On each trial, an observer attempted to walk to the target location along a direct or indirect path. The ability to mentally keep track of the target location without concurrent perceptual information about it (spatial updating) was assessed in terms of the separation between the stopping points for the 2 paths. Updating performance was very nearly the same for the 2 modalities, indicating that once an internal representation of a location has been determined, subsequent updating performance is nearly independent of the modality used to specify the representation.

Memory for multidimensional source information.

Abstract: Source memory may comprise recollection of multiple features of the encoding episode. To analyze the simultaneous representation and retrieval of those multiple features, a multinomial memory model is presented that measures memory for crossed dimensions of source information. The first experiment investigated the validity of the new model. The model showed an excellent statistical fit to empirical data, and the parameters of multidimensional source memory were sensitive to manipulations of source similarity on distinct dimensions. The second experiment used the model to test the hypothesis that source memory for individual context attributes is stochastically related in the case of conscious recollection but independent in the case of familiarity-based recognition judgments. The prediction was supported by the introduction of a "remember"-"know" distinction in a multidimensional source memory test.

Age dissociates recency and lag recency effects in free recall.

Abstract: The temporal relations among word-list items exert a powerful influence on episodic memory retrieval. Two experiments were conducted with younger and older adults in which the age-related recall deficit was examined by using a decomposition method to the serial position curve, partitioning performance into (a) the probability of first recall, illustrating the recency effect, and (b) the conditional response probability, illustrating the lag recency effect (M. W. Howard & M. J. Kahana, 1999). Although the older adults initiated recall in the same manner in both immediate and delayed free recall, temporal proximity of study items (contiguity) exerted a much weaker influence on recall transitions in older adults. This finding suggests that an associative deficit may be an important contributor to older adults' well-known impairment in free recall.

Dynamics and constraints in insight problem solving.

Abstract: This article reports 2 experiments that investigated performance on a novel insight problem, the 8-coin problem. The authors hypothesized that participants would make certain initial moves (strategic moves) that seemed to make progress according to the problem instructions but that nonetheless would guarantee failure to solve the problem. Experiment 1 manipulated the starting state of the problem and showed that overall solution rates were lower when such strategic moves were available. Experiment 2 showed that failure to capitalize on visual hints about the correct first move was also associated with the availability of strategic moves. The results are interpreted in terms of an information-processing framework previously applied to the 9-dot problem. The authors argue that in addition to the operation of inappropriate constraints, a full account of insight problem solving must incorporate a dynamic that steers solution-seeking activity toward the constraints.

The processing role of structural constraints on the interpretation of pronouns and anaphors.

Abstract: The authors report 6 self-paced word-by-word reading studies of how morphosyntactic agreement, focus status, and the structural constraints of binding theory apply and interact during the online interpretation of pronouns (e.g., him, her) and anaphors (e.g., himself, each other). Previous studies held that structural conditions on coreference work as interpretive filters that impose exceptionless limits on which antecedent candidates can be evaluated by subsequent, content-based processes. These experiments instead support an interactive-parallel-constraint model, in which multiple weighted constraints (including constraints on binding) simultaneously influence the net activation of a candidate during preselection stages of antecedent evaluation. Accordingly, structurally inaccessible candidates can interfere with antecedent selection if they are both prominent in focus structure and gender-number compatible with the pronoun or anaphor.

Distinguishing prototype-based and exemplar-based processes in dot-pattern category learning

Abstract: The authors contrast exemplar-based and prototype-based processes in dot-pattern categorization. In Experiments 1A and 1B, participants provided similarity ratings of dot-distortion pairs that were distortions of the same originating prototype. The results show that comparisons to training exemplars surrounding the prototype create flat typicality gradients within a category and small prototype-enhancement effects, whereas comparisons to a prototype center create steep typicality gradients within a category and large prototype-enhancement effects. Thus, prototype and exemplar theories make different predictions regarding common versions of the dot-distortion task. Experiment 2 tested these different predictions by having participants learn dot-pattern categories. The steep typicality gradients, the large prototype effects, and the superior fit of prototype models suggest that participants refer to-be-categorized items to a representation near the category's center (the prototype), and not to the training exemplars that surround the prototype.

Comparing prototype-based and exemplar-based accounts of category learning and attentional allocation.

Abstract: Exemplar theory was motivated by research that often used D. L. Medin and M. M. Schaffer's (1978) 5/4 stimulus set. The exemplar model has seemed to fit categorization data from this stimulus set better than a prototype model can. Moreover, the exemplar model alone predicts a qualitative aspect of performance that participants sometimes show. In 2 experiments, the authors reexamined these findings. In both experiments, a prototype model fit participants' performance profiles better than an exemplar model did when comparable prototype and exemplar models were used. Moreover, even when participants showed the qualitative aspect of performance, the exemplar model explained it by making implausible assumptions about human attention and effort in categorization tasks. An independent assay of participants' attentional strategies suggested that the description the exemplar model offers in such cases is incorrect. A review of 30 uses of the 5/4 stimulus set in the literature reinforces this suggestion.

Ambiguity and synonymy effects in lexical decision, naming, and semantic categorization tasks: interactions between orthography, phonology, and semantics.

Abstract: In this article, ambiguity and synonymy effects were examined in lexical decision, naming, and semantic categorization tasks. Whereas the typical ambiguity advantage was observed in lexical decision and naming, an ambiguity disadvantage was observed in semantic categorization. In addition, a synonymy effect (slower latencies for words with many synonyms than for words with few synonyms) was observed in lexical decision and naming but not in semantic categorization. These results suggest that (a) an ambiguity disadvantage arises only when a task requires semantic processing, (b) the ambiguity advantage and the synonymy disadvantage in lexical decision and naming are due to semantic feedback, and (c) these effects are determined by the nature of the feedback relationships from semantics to

The dynamics of intention retrieval and coordination of action in event-based prospective memory.

Abstract: Event-based prospective memory requires responding to cues in the environment that are associated with a previously established intention. Some researchers believe that intentions reside in memory with an above baseline level of activation, a phenomenon called the intention superiority effect. The authors of this study predicted that intention superiority would be masked by additional cognitive processes associated with successful event-based prospective memory. These additional processes include noticing the cue, retrieving the intention, and coordinating intention execution with the ongoing activity. In 3 experiments, intention superiority was demonstrated by faster latencies to the ongoing activity on failed prospective trials and the existence of the additional processes was demonstrated by slower latencies on successful trials. This study demonstrates the importance of investigating the microstructure of the cognitive components involved with processing and responding to an event-based prospective memory cue.

Word-frequency and phonological-neighborhood effects on verbal short-term memory.

Abstract: Immediate memory span and maximal articulation rate were assessed for word sets differing in frequency, word-neighborhood size, and average word-neighborhood frequency. Memory span was greater for high- than low-frequency words, greater for words from large than small phonological neighborhoods, and greater for words from high- than low-frequency phonological neighborhoods. Maximal articulation rate was also facilitated by word frequency, phonological-neighborhood size, and neighborhood frequency. In a final study all 3 lexical variables were found to influence the recall outcome for individual words. These effects of phonological-word neighborhood on memory performance suggest that phonological information in long-term memory plays an active role in recall in short-term-memory tasks, and they present a challenge to current theories of short-term memory.

Preparatory processes in the task-switching paradigm: evidence from the use of probability cues.

Abstract: The purpose of the investigations was to dissociate processes of task preparation from task execution in the task-switching paradigm. The basic assumption was that task repetitions have 2 advantages over task shifts: an activation advantage as a result of the execution of the same task type in the pretrial, and an expectation advantage, because participants, in general, implicitly expect a repetition. In Experiments 1-3, the authors explicitly manipulated expectancies by presenting cues that announced a shift and/or a repetition with probabilities of 1.00, .75, .50, or .25. Increasing latencies with decreasing probability for shifts and repetitions show that the expectation advantage can be equalized by preparation. However, the activation advantage represented by constant shift costs between tasks of the same probability is not penetrable by preparation. In Experiments 4 and 5, the authors found evidence that preparation involves activation of the expected task and inhibition of distracting tasks.

Are performance predictions for text based on ease of processing

Abstract: In 4 experiments, the authors evaluated the hypothesis that performance predictions for text are based on ease of processing. In each experiment, participants read texts, predicted their performance for each one, and then were tested. Ease of processing was manipulated by having participants read texts that varied in coherence. Coherence was varied by manipulating causal relatedness across sentence pairs (Experiments 1 and 2) and by altering the structure of sentences within paragraphs (Experiment 3). In these experiments, prediction magnitudes increased as coherence increased, suggesting that predictions were based on processing ease. In Experiment 4, prediction magnitudes were greater for intact paragraphs than for paragraphs with letters deleted from some of the words. Discussion focuses on resolving apparent inconsistencies in the literature concerning whether processing ease influences performance predictions.

On the form of ROCs constructed from confidence ratings.

Abstract: A classical question for memory researchers is whether memories vary in an all-or-nothing, discrete manner (e.g., stored vs. not stored, recalled vs. not recalled), or whether they vary along a continuous dimension (e.g., strength, similarity, or familiarity). For yes-no classification tasks, continuous- and discrete-state models predict nonlinear and linear receiver operating characteristics (ROCs), respectively (D. M. Green & J. A. Swets, 1966; N. A. Macmillan & C. D. Creelman, 1991). Recently, several authors have assumed that these predictions are generalizable to confidence ratings tasks (J. Qin, C. L. Raye, M. K. Johnson, & K. J. Mitchell, 2001; S. D. Slotnick, S. A. Klein, C. S. Dodson, & A. P. Shimamura, 2000, and A. P. Yonelinas, 1999). This assumption is shown to be unwarranted by showing that discrete-state ratings models predict both linear and nonlinear ROCs. The critical factor determining the form of the discrete-state ROC is the response strategy adopted by the classifier.

Sequence effects in categorization of simple perceptual stimuli

Abstract: Categorization research typically assumes that the cognitive system has access to a (more or less noisy) representation of the absolute magnitudes of the properties of stimuli and that this information is used in reaching a categorization decision. However, research on identification of simple perceptual stimuli suggests that people have very poor representations of absolute magnitude information and that judgments about absolute magnitude are strongly influenced by preceding material. The experiments presented here investigate such sequence effects in categorization tasks. Strong sequence effects were found. Classification of a borderline stimulus was more accurate when preceded by a distant member of the opposite category than by a distant member of the same category. It is argued that this category contrast effect cannot be accounted for by extant exemplar or decision-bound models of categorization. The effect suggests the use of relative magnitude information in categorization. A memory and contrast model illustrates how relative magnitude information may be used in categorization.

Sublexical or lexical effects on serial recall of nonwords

Abstract: S. E. Gathercole, C. R. Frankish, S. J. Pickering, and S. Peaker (1999) reported 2 experiments in which they manipulated phonotactic properties of nonword stimuli and observed the effects on serial recall. Their results show superior recall for items consisting of more frequent phoneme pairs (biphone frequency). Biphone frequency was counted as the number of 3 phoneme words in which the phoneme pair occurs. In the first experiment of the current article, the authors made the same manipulation while controlling for the number of lexical neighbors and found no effect of biphone frequency. In the second experiment, the authors manipulated neighborhood size while controlling biphone frequency and found a significant effect of neighborhood size. The authors argued that serial recall of nonwords is influenced by lexical rather than sublexical knowledge.

Concurrent learning of temporal and spatial sequences.

Abstract: In a serial reaction time task, stimulus events simultaneously defined spatial and temporal sequences. Responses were based on the spatial dimension. The temporal sequence was incidental to the task, defined by the response-to-stimulus intervals in Experiment 1 and stimulus onset asynchronies in Experiment 2. The two sequences were either of equal length and correlated or of unequal length. In both experiments, spatial learning occurred regardless of sequence length condition. In contrast, temporal learning occurred only in the correlated condition. These results suggest that timing is an integrated part of action representations and that incidental learning for a temporal pattern does not occur independently from the action. Interestingly, sequence learning was enhanced in the correlated condition, reflecting the integration of spatial-temporal information. Since the seminal article by Lashley (1951) on “the problem of serial order,” (p. 112) much research has been directed toward understanding the cognitive mechanisms underlying the acquisition of skill in performing sequential activities. Fluent performance of many sequential activities, such as speech, music, and sports, requires carrying out component actions in the appropriate order. However, just as important as the order of component activities in performing these tasks is the relative timing of these actions. Sometimes, timing is crucial in explicitly defining the task, as in the case of musical performance. In other tasks, timing impacts the smoothness and skillfulness of performance, as in the case of adjusting the speed and direction of a car when driving down a familiar road. How are the order of actions and their temporal relations represented? Whether timing is assumed to be represented explicitly in a motor program (Schmidt, 1980; Viviani & Terzuolo, 1980) or considered an emergent property of the actions themselves (Kelso, 1981; Rumelhart & Norman, 1982), existing theories of timing differ widely in terms of the relationship between sequencing and timing. According to Rosenbaum (1985, 1987), the scheduling of actions is based on the joint specification of the order of actions and their timing. Consistent with this view, there is evidence that information about timing can be integrated with information about the action sequence (Summers, 1975, 1977). Such theories assume sequencing and timing of actions are inseparable. In contrast, the notion of a generalized motor program allows one to postulate

Assessing the inhibitory account of retrieval-induced forgetting with implicit-memory tests.

Abstract: Five experiments examined whether retrieval-induced-forgetting effects are observed for implicit tests of memory. In each experiment participants first studied category-exemplar paired associates, then practiced retrieval for a subset of items from a subset of categories before finally completing memory tests for all the studied items. In standard fashion, inhibition was measured as the performance difference of unpracticed items from practiced categories and unpracticed items from unpracticed categories. Across the 5 experiments poorer performance for unpracticed items was seen in conceptual implicit memory (category generation and category matching) but not in perceptual implicit memory (stem completion, perceptual identification). Thus, retrieval-induced-forgetting effects are limited to tests of conceptual memory.

Environmental context and recognition: The role of recollection and familiarity

Abstract: Evidence for effects of changed environmental context on recognition has been equivocal. Using 3 experiments, the author investigated the role of environmental context from a dual-processing approach. Experiment 1 showed that testing word recognition in a novel context led to a reliable decrement but only for recognition accompanied by conscious recollection, with familiarity-based recognition judgments being unaffected. This was replicated in Experiment 2 using stimuli that were novel to the participants (nonwords). Experiment 3 showed that the decrement in recollection also occurred when the changedcontext condition involved presenting items in a different but familiar context. The results suggest that effects of environmental context will only be found when recognition is accompanied by conscious recollection and that this effect is due to a specific item– context association.