Contrasting effects of repetition across tasks: Implications for understanding the nature of refractory behavior and models of semantic memory

We describe a patient (J.M.) who showed “refractory” behavior in picture—word matching tasks—that is, his performance became poorer when items were repeated. This contrasts with the facilitatory effects of repetition usually observed in normal participants. We show for the first time that there can be facilitatory effects of repetition on some tasks, even though refractory behavior is shown on the same items in other tasks. In particular, in Experiments 1 and 2, we demonstrate that J.M. showed contrasting effects of repetition across different components of the language system: There were facilitatory effects of repetition priming on lexical decision but refractory behavior on picture—word matching. In Experiments 3 and 4, we demonstrate that J.M. showed contrasting effects of repetition within the same system (semantic memory). His performance became refractory when items were repeated in picture—word matching (Experiment 3), but it was facilitated when items were repeated in superordinate categorization (Experiment 4). These contrasting patterns of facilitation and interference from repetition priming have implications for understanding the nature of refractory behavior and for constraining theoretical accounts of semantic memory.     

Effect of repetition proportion on language-driven anticipatory eye movements

Previous masked priming research in word recognition has demonstrated that repetition priming is influenced by experiment-wise information structure, such as proportion of target repetition. Research using naturalistic tasks and eye-tracking has shown that people use linguistic knowledge to anticipate upcoming words. We examined whether the proportion of target repetition within an experiment can have a similar effect on anticipatory eye movements. We used a word-to-picture matching task (i.e., the visual world paradigm) with target repetition proportion carefully controlled. Participants' eye movements were tracked starting when the pictures appeared, one second prior to the onset of the target word. Targets repeated from the previous trial were fixated more than other items during this preview period when target repetition proportion was high and less than other items when target repetition proportion was low. These results indicate that linguistic anticipation can be driven by short-term within-experiment trial structure, with implications for the generalization of priming effects, the bases of anticipatory eye movements, and experiment design.     

Transfer-appropriate processing (TAP)

Transfer-appropriate processing (TAP), as applied to implicit memory, has tended to emphasize general forms of processing (e.g., perceptual or conceptual processing). In the present studies, the TAP principle was employed in a more specific manner in order to more precisely assess the relations between the processing engaged during first exposure and that engaged during second exposure to items. Thirteen experiments used a two-phase, cross-task design in which participants engaged in different combinations of seven specific intentional tasks between Phase 1 and Phase 2. Maximum repetition priming was found when tasks were the same in Phases 1 and 2. When Phase 1 and Phase 2 tasks differed, there were lesser, or no, repetition priming effects, depending on the particular combination of tasks. The results demonstrate the importance of the specific intentional processes engaged during repetition priming and the potential heuristic value of TAP, as a principle and methodology, for exploring the organization of memory and related process models.     

Repeated study of items with and without repeated context: aging effects on memory discriminability

Presenting items multiple times during encoding is a common way to enhance recognition accuracy. Under such conditions, older adults often show an increase in false recognition that counteracts benefits of repeated study. Using a false-memory paradigm with related study items and related lures, we tested whether repetition within the same encoding task or repetition across two different encoding tasks would be more beneficial to older adults’ memory discriminability. Results showed that, compared to items not repeated at study, items repeated in the same context and items repeated across different contexts showed improvements in memory discriminability in both young and older adults. This improvement was primarily reflected in improved recollection responses for both age groups across both repeat study conditions, as compared to no repetition. Importantly, the results demonstrated that repetition can be used to successfully mitigate age-related deficits by increasing memory discriminability and without incurring a cost of false recognition specific to any one age group.     

Components of activation: repetition and priming effects in lexical decision and recognition

Activation decay functions were examined in two different tasks: lexical decision and word recognition. Activation (amount of facilitation) was measured both for item repetition and for priming between newly learned associates. Results indicate that there are at least three different components of activation: a short-term component that decays with one or two intervening items and that appears to be common to priming and repetition; an intermediate component for repetition in recognition; and a long-term component for repetition.     

Effects of Domain,Retention Interval,and Information Load on Young and Older Adults’ Visuospatial Working Memory

Age-related differences in visuospatial working memory were examined in 69 young adults and 49 older adults exposed to three pairs of tasks. Each pair consisted of one task involving information about the form or appearance of items and another task involving information about item locations. The first pair of tasks manipulated retention interval and required maintaining information about one item. The second pair also manipulated retention interval and required maintaining information about multiple items presented simultaneously. The third pair manipulated the number of sequentially presented items. Analyses of the first two pairs of tasks revealed significant age deficits in working memory for spatial locations but not in working memory for visual features. Notably, there were no age differences in the effect of retention interval on any of the four tasks, suggesting that visuospatial information is lost at similar rates in older and young adults. Analyses of the third pair of tasks revealed that, regardless of domain, increasing the amount of information impaired older adults’ memory performance to a greater extent than young adults’ performance. Thus, the present results suggest differences in basic working memory capacity in both domains, but a lack of age differences in rates of forgetting from working memory, and greater age-related deficits in the spatial domain than in the object domain.     

Order or disorder? Impaired Hebb learning in dyslexia

The present study offers an integrative account proposing that dyslexia and its various associated cognitive impairments reflect an underlying deficit in the long-term learning of serial-order information, here operationalized as Hebb repetition learning. In nondyslexic individuals, improved immediate serial recall is typically observed when one particular sequence of items is repeated across an experimental session, a phenomenon known as the Hebb repetition effect. Starting from the critical observation that individuals with dyslexia seem to be selectively impaired in cognitive tasks that involve processing of serial order, the present study is the first to test and confirm the hypothesis that the Hebb repetition effect is affected in dyslexia, even for nonverbal modalities. We present a theoretical framework in which the Hebb repetition effect is assumed to be a laboratory analogue of naturalistic word learning, on the basis of which we argue that dyslexia is characterized by an impairment of serial-order learning that affects language learning and processing.     

Individual differences in phonological learning and verbal STM span

A relationship between phonological short-term memory tasks (e.g., nonword repetition, digit span) and vocabulary learning in both experimental and real-life conditions has been reported in numerous studies. A mechanism that would explain this correlation is, however, not known. The present study explores the possibility that it is the quality of phonological representations that affects both short-term recall and long-term learning of novel wordlike items. In Experiment 1, groups with relatively good and poor span for pseudowords were established. The good group was found to perform better at explicit memory tasks tapping the incidental learning of a limited stimulus pool used in an auditory immediate serial pseudoword recall task. In Experiment 2, the results of Experiment 1 were replicated when experience of correct recall was controlled. In Experiment 3, the immediate recall performance of the good group was found to benefit more than that of the poor group from syllable repetition within stimulus pools. It is concluded that the efficiency of a process that creates phonological representations is related both to short-term capacity for verbal items, and to long-term phonological learning of the structure of novel phonological items.     

Strategic influences on recollection in the exclusion task: Electrophysiological evidence

One assumption underlying the use of the exclusion task as part of the process dissociation procedure is that studied items are successfully excluded only when they are recollected. The present study employed event-related potentials (ERPs) to demonstrate that successful exclusion does not necessarily require recollection. In two experiments, the study tasks for to-be-excluded items were identical, but the tasks employed withtarget items differed, giving better memory for these items in Experiment 1 than in Experiment 2. Successfully excluded items elicited the ERP signature for recollection—theleft parietal old/new effect—in Experiment 2 only. These findings indicate that the subjects adopted different retrieval strategies in the two experiments. It is suggested that they made more use of source information about to-be-excluded items in the second experiment than in the first.     

Repetition priming in an auditory lexical decision task: Effects of lexical status

The effect of lexical status on the time course of repetition priming was examined in an auditory lexical decision task. Words and nonwords were repeated at lags of 0, 1, 4, and 8 items (Experiment 1A) and 0, 2, 4, and 8 items (Experiment 1B). The pattern of repetition effects differed for words and nonwords in that repetition priming for nonwords at lag 0 was significantly greater than for words. The magnitude of this effect decreased when one or more items intervened. A second experiment, replicating Experiment 1A with visual presentation, clarified that the greater magnitude of repetition priming for nonwords at lag 0 is unique to the auditory modality. This finding suggests that in the course of forming a stable perceptual representation, the details of the acoustic/phonological information of an auditory stimulus are more readily available for nonwords than for words. The capacity to carry this phonological information is limited, however, and can only be maintained until another stimulus is encountered.     

Detrimental influence of contextual change on spacing effects in free recall

Two experiments were conducted to determine the mechanism underlying the spacing effect in free-recall tasks. Participants were required to study a list containing once-presented words as well as massed and spaced repetitions. In both experiments, presentation background at repetition was manipulated. The results of Experiment 1 demonstrated that free recall was higher for massed items repeated in a different context than for massed items repeated in the same context, whereas free recall for spaced items was higher when repeated in the same context. Furthermore, a spacing effect was shown for words repeated in the same context, whereas an attenuated spacing effect was revealed for words repeated in a different context. These findings were replicated in Experiment 2 under a different presentation background manipulation. Both experiments seem to be most consistent with a model that combines the contextual variability and the study-phase retrieval mechanism to account for the spacing effect in free-recall tasks.     

Exploring the false recognition of category exemplars: Effects of divided attention and explicit generation

Two experiments used the category repetition procedure (Dewhurst & Anderson, 1999) to test the hypothesis that false remember (R) responses occur because participants generate associates to items presented at study. Participants in Experiment 1 studied the categorised lists either with full attention or whilst performing one of two secondary tasks (articulatory suppression or random number generation). Both secondary tasks led to a reduction in the number of false R responses, with random number generation producing the greater effect. Experiment 2 manipulated the presentation duration of study items and the instructions given to participants. The numbers of false R responses were not influenced by presentation duration, but increased when participants were explicitly instructed to make associations to study items. The findings support the view that false R responses are caused by the activation of semantic associates at encoding.     

Inhibition of return and repetition priming effects in localization and discrimination tasks.

Inhibition of return (IOR) refers to slower responding to a stimulus that is presented at the same, rather than a different location as a preceding, spatially nonpredictive, stimulus. Repetition priming refers to speeded responding to a stimulus that duplicates the visual characteristics of a stimulus that precedes it. IOR and repetition priming effects interact in nonspatial discrimination tasks but not in localization tasks; three experiments examined whether this is due to processing differences or due to response differences between tasks. Two stimuli, S1 and S2, occurred on each trial. In Experiment 1, S1 and S2 were both peripheral arrows; in Experiment 2, S1 was a central arrow and S2 was a peripheral nondirectional rectangle; in Experiment 3, S1 was a peripheral nondirectional rectangle and S2 was a peripheral arrow. S1 never required a response; S2 required a localization or a discrimination response. Despite evidence that form information was likely extracted from the arrow stimuli, the localization task revealed no repetition priming: IOR occurred regardless of shared visual identity of the S1 and S2 arrows. The discrimination task revealed IOR only when the visual identity changed from S1 to S2; otherwise, facilitation occurred. These results suggest that IOR is masked by repetition priming only when the response depends on the explicit processing of form information; repetition priming does not occur when such information is extracted automatically but is task (and response) irrelevant.     

The effect of repetition of items on two phases of paired associate learning

An investigation is reported in which the effect of repetition of items on two learning tasks is determined. These tasks are considered to be analogous to the response-learning and associative phases of paired associate learning. The findings tend to support the hypotheses under investigation, that response learning is an all-or-none occurrence and that the associative phase may be explained by the dual factor hypothesis.     

Stimulus–response bindings contribute to item switch costs in working memory

In counter updating tasks, responses are typically faster when items repeat than when they change (item switch costs). The present study explored the contribution of stimulus–response bindings to these item switch costs. In two experiments, we orthogonally manipulated the repetition/switch of to-be-counted items and the repetition/switch of required manual responses. Item switch costs were considerably lower when item switches were accompanied by response switches than when accompanied by response repetitions. Experiment 2 showed that, although there was also a smaller contribution from stimulus–stimulus bindings (i.e., shape-location), the major part was due to stimulus-response bindings. These results show that in the widely used standard version of the counter updating task, a considerable portion of item switch costs is caused by the unbinding of stimulus–response bindings rather than by processes of switching items in working memory.     

Toward a unified account of spacing effects in explicit cued-memory tasks

Memory for repeated items improves when presentations are spaced during study. This effect is found in memory tasks using different types of material, paradigms, and participant populations. Although several explanations have been proposed, none explains the presence of spacing effects in cued-memory tasks for unfamiliar stimuli. Two experiments assessed the spacing effect on a yes-no recognition-memory task using nonwords and words as targets. The main results showed that changing the font between repeated occurrences of targets at study removed the spacing effect for nonwords only. A 3rd experiment using lexical decision showed that the font manipulation reduced repetition priming of nonwords when items were repeated at Lag 0. These results suggest that short-term perceptual priming supports spacing effects in cued-memory tasks for unfamiliar stimuli.     

Repetition priming of access to biographical information from faces

Two experiments examined repetition priming on tasks that require access to semantic (or biographical) information from faces. In the second stage of each experiment, participants made either a nationality or an occupation decision to faces of celebrities, and, in the first stage, they made either the same or a different decision to faces (in Experiment 1) or the same or a different decision to printed names (in Experiment 2). All combinations of priming and test tasks produced clear repetition effects, which occurred irrespective of whether the decisions made were positive or negative. Same-domain (face-to-face) repetition priming was larger than cross-domain (name-to-face) priming, and priming was larger when the two tasks were the same. It is discussed how these findings are more readily accommodated by the Burton, Bruce, and Johnston () model of face recognition than by episode-based accounts of repetition priming.     

Repetition priming of access to biographical information from faces

Two experiments examined repetition priming on tasks that require access to semantic (or biographical) information from faces. In the second stage of each experiment, participants made either a nationality or an occupation decision to faces of celebrities, and, in the first stage, they made either the same or a different decision to faces (in Experiment 1) or the same or a different decision to printed names (in Experiment 2). All combinations of priming and test tasks produced clear repetition effects, which occurred irrespective of whether the decisions made were positive or negative. Same-domain (face-to-face) repetition priming was larger than cross-domain (name-to-face) priming, and priming was larger when the two tasks were the same. It is discussed how these findings are more readily accommodated by the Burton, Bruce, and Johnston (1990) model of face recognition than by episode-based accounts of repetition priming.     

Repetition and verbal STM in transcortical sensory aphasia: a case study

The repetition performance of a patient (S.T.) with transcortical sensory aphasia is examined in four experiments with particular emphasis on the STM capacities underlying her performance. S.T.'s repetition of word strings exceeding her span (two words) is characterized by good recall of the final items and a strong tendency to lose the initial items in the input string. This pattern contrasts with the serial position effects observed in a phonologically based STM impairment, and it is suggested that a lexical-semantic impairment, also evident in S.T.'s naming and lexical comprehension, contributes to her inability to retain the primacy portions of the input string. Lexical effects obtained in her reproduction of words and nonwords, as well as word strings (Experiments 1 and 2), indicate that under conditions of impaired semantics S.T. is relying on lexical phonological information to repeat. Priming by repeated exposure (Experiment 3) failed to improve her repetition performance, indicating that access to lexical information is brief and dependent on recent phonological input. In Experiment 4, the role of syntactic structure in S.T.'s sentence repetition was examined, and it was shown that syntactic structure affects the recall of order information, but not the number of items recalled. The repetition and verbal STM abilities of this patient, in light of her total language profile, are then evaluated in the context of a language-based view of verbal STM.     

A comparison of the performance of Persian speaking children who do and do not stutter on three nonwords repetition tasks

PurposeThe purpose of the study was to examine the performance of Persian speaking children who stutter (CWS) and children who do not stutter (CWNS) on three nonword repetition tasks, while also focusing on which task and scoring method best differentiates the two groups of children.MethodThirty CWS and 30 CWNS between the ages of 5;0 to 6;6 completed three nonword repetition tasks that varied in complexity. Each task was scored using two methods: nonwords correct and phonemes correct. Between-group differences in performance on each task were examined, along with disfluencies for CWS and the task and scoring method that best differentiated the CWS and CWNS.ResultsThe findings revealed that, across all three nonword repetition tasks, the CWS consistently produced fewer nonwords correct and phonemes correct than the CWNS group at virtually all syllable lengths. The CWS produced more disfluencies on longer nonwords than shorter nonwords in all three nonword repetition tasks. The nonword repetition task with lower wordlikeness and more phonologically complex items best differentiated the two groups of children. Findings further revealed that discriminative accuracy was highest for scoring based on the number of phonemes produced correctly.ConclusionFindings provide further evidence to suggest that CWS may have difficulty with phonological working memory and/or phonological processing.