Fragment Completion Research Articles

Study effort versus distinctiveness in the recollection of veridical and illusory memories

In past research, stimulus distinctiveness and study effort have been claimed to promote the development of distinctive memories, which in turn have been considered critical for enhancing veridical recollection and reducing illusory memory experiences. In the present investigation, stimulus distinctiveness, obtained by displaying text-redundant pictorial information at study, was pitted against study effort to determine whether either factor would be more beneficial to veridical recall and more detrimental to illusory recall than the other. Subjects first completed word fragments with or without the aid of an image of each word's referent and then performed a recall test. It was found that when images were useful to the encoding task (fragment completion), their presence at study enhanced veridical recall and reduced illusory memories more than any additional encoding effort.

Real-Time Computation of Japanese Exclamatives and the Strength of Locality Biases in Sentence Comprehension

This paper investigates mechanisms of long-distance dependency formation in language comprehension, using experimental data on the processing of Japanese interrogatives and exclamatives to explore the nature of locality biases in parsing. Findings on the processing of exclamative wh-phrases are compared to previous results involving the processing of interrogative wh-phrases, revealing both similarities and differences. Experiment 1 uses a sentence fragment completion task with in-situ and fronted exclamative and interrogative wh-phrases. Both types of in-situ wh-phrase show a strong bias for local generation of licensing particles. Conditions with fronted wh-phrases show a contrast between interrogative and exclamative wh-phrases: interrogatives show a bias for interpretation in an embedded clause, replicating previous evidence for a long-distance scrambling bias in Japanese (Aoshima, Phillips, & Weinberg, 2004); in contrast, the long-distance scrambling bias is weaker for fronted exclamative wh-phrases. Experiment 2 uses an on-line self-paced reading task to investigate the processing consequences of expectations for a local licensor for in-situ exclamative wh-phrases. Results indicate processing disruption when readers fail to encounter a licensor for an exclamative wh-phrase at the first possible verb position, although the disruption is weaker than the Typing Mismatch Effect shown for interrogatives in previous studies by Miyamoto and Takahashi (2002). Different possible accounts of the parallels and contrasts between processing of interrogatives and exclamatives are discussed.

Eliminating the memory blocking effect

Six experiments investigated the memory blocking effect (MBE) in which exposure to orthographically similar words (e.g., BALLOON) impairs one's ability to complete a similar fragment (e.g., BAL_ON_, solution is BALCONY). Experiments 1 and 2 demonstrated that blocking is not observed after a 72-hour delay; however, repetition priming was observed after the same delay. Experiments 3 and 4 showed that presenting unrelated semantic information during the fragment completion test eliminates blocking. Experiment 5 demonstrated that the MBE persists despite directed-forgetting instructions, and Experiments 5 and 6 demonstrated that activating both the solutions and blocking words for a particular fragment at study eliminates blocking. Collectively, the data demonstrate that reading orthographically similar primes automatically triggers retrieval of the blocking word and an executive control process works to manage this interference. A working framework that describes how an executive control mechanism could govern memory retrieval in the memory-blocking paradigm is presented to stimulate development of more advanced theoretical models that can explain blocking.

“Fragment errors” in deep dysgraphia: Further support for a lexical hypothesis

In addition to various lexical errors, the writing of patients with deep dysgraphia may include a large number of segmental spelling errors, which increase towards the end of the word. Frequently, these errors involve deletion of two or more letters resulting in so-called “fragment errors”. Different positions have been brought forward regarding their origin, including rapid decay of activation in the graphemic buffer and an impairment of more central (i.e., lexical or semantic) processing. We present data from a patient (M.D.) with deep dysgraphia who showed an increase of segmental spelling errors towards the end of the word. Several tasks were carried out to explore M.D.'s underlying functional impairment. Errors affected word-final positions in tasks like backward spelling and fragment completion. In a delayed copying task, length of the delay had no influence. In addition, when asked to recall three serially presented letters, a task which had not been carried out before, M.D. exhibited a preference for the first and the third letter and poor performance for the second letter. M.D.'s performance on these tasks contradicts the rapid decay account and instead supports a lexical-semantic account of segmental errors in deep dysgraphia. In addition, the results fit well with an implemented computational model of deep dysgraphia and segmental spelling errors.

Review of Implicit measures of attitudes.

Implicit Measures of Attitudes, by Bernd Wittenbrink & Norbert Schwarz (Eds.). The Guilford Press, 2007, 294 pages (ISBN-10: 1-59385-402-1, ISBN-13: 978-1-59385-402-7, US $38.00 Hardcover) Reviewed by STEVEN M. SMITH DOI : 10.1037/0708-5591.49.2.177 Well before the concept of was first articulated by social psychologists, people expended tremendous energy trying to understand and assess people's opinions of many different topics. Almost immediately after the development of formal attitude measures, there was recognition that at times people may be unwilling or unable to express their true attitudes toward certain topics. For example, if a person is asked about potentially embarrassing topics or topics where social desirability factors may play a role, they may misrepresent their attitude. Alternatively, people may simply be unaware of their true opinion on an issue. Thus, in addition to direct or measures of attitudes (e.g., self-report and surveys or interviewbased measures), we have seen the development of more indirect or measures of attitudes. However, because many early implicit measures were cumbersome (such as the Thematic Apperception Test) and/or had reliability or validity issues, explicit measures of attitudes became dominant. Despite the fact that explicit measures provided a cheap, simple, reliable and valid way to assess attitudes, the limitations of these measures remained an issue. With the advent of computerbased testing and other high-tech methodologies, there has been a dramatic resurgence of the use of implicit attitude measures in the last two decades. Thus it is clear that Bernd Wittenbrink and Norbert Schwarz have produced a very timely volume. The stated goals of Wittenbrink and Schwarz's book are to educate the reader about the value of implicit measures of attitudes, as well as to provide a handbook of sorts for the neophyte wanting to learn how to use the variety of implicit attitude measures available. In addition, the editors want to provide a critical assessment of the state of implicit attitude measurement in terms of the very definition of an implicit measure, as well as the general reliability and validity of these measures. Finally, the editors want to provide directions for future research in the area of implicit attitude measurement. As such, Wittenbrink and Schwarz hope that this text will be a resource book for both new graduate students and established researchers in the field. In general, I believe the editors have accomplished their goals. After the editors' introductory chapter, which gives an overview of the development of implicit attitude measurement as well as an overview of the rest of the volume, the book is broken down into two sections: Procedures and Their Implementation and Critical Perspectives. The procedures and implementation section includes chapters on the most popular implicit measures currently in use. Wittenbrink begins by exploring work that has been done on attitude priming; the procedure that initiated the resurgence of implicit attitude measurement in the 1980s and 1990s. The next chapter, authored by Kristin Lane, Mahzarin Banaji, Brian Nosek, and Anthony Greenwald covers the Implicit Association Test (IAT), which is clearly the most popular implicit attitude measurement procedure currently in use. Patrick Vargas, Denise Sekaquaptewa and William von Hippel follow with a chapter on lowtech paper and pencil implicit measures. For me, this chapter was the most pleasantly surprising in the book. It provides many cheap and accessible methods to measure implicit attitudes, and barkens back to the early days of implicit measures, making the distinction between and deliberative measures. Furthermore, the authors describe a number of implicit measures that do not require spontaneous responses (such as Word Fragment Completion, paper and pencil versions of the IAT, and the information error test) which highlights one of the issues surrounding the definition of measures of attitudes. …

The representation of morphologically complex words in the developing lexicon*

The study reported here examined the manner in which children represent morphologically complex words in the lexicon. Children in grades 1 to 5 completed a fragment completion task to assess the priming effects of morphologically related words. Both inflected and derived words (e.g. needs and needy, respectively) were more effective primes than control words (e.g. needle) that share similar orthography and phonology with the target word (e.g. need). These effects were consistent across the developmental period studied. Further, equivalent priming effects from the inflected and derived forms suggest that these word types are represented similarly in the developing lexicon.

When do primes go bad? A corpus of orthographically related primes that inhibit fragment completion

The memory block effect (MBE) occurs when orthographically similar words inhibitretrieval. Previous studies have published 55 different stimuli that produce the MBE in word fragment completion. This small number of stimuli constrains experimental designs, presents serious obstacles for using neuroimaging to elucidate neural substrates of blocking, and raises concern that the MBE is limited to a particular group of words. A pool of 315 stimulus words was tested in a traditional MBE paradigm, and the results demonstrated that the MBE generalizes to other stimuli. This study also expands the number of stimuli that produce the MBE because 185 new stimuli produced blocking effects. As a result, the current list of 240 MBE stimuli can be used for word fragment research including cognitive neuroscience investigations of retrieval inhibition. A table of MBE stimuli is available in an archived appendix that can be downloaded from www.psychonomic.org/archive.

A Comparison of Implicit Memory Tests in Schizophrenic Patients and Normal Controls

The objective of the current study was to compare the performance of schizophrenic patients and normal controls on implicit memory tests. Two neuropsychological tasks were administered to 29 patients and normal participant samples. The implicit tests were: Word fragment completion and Word production from semantic categories. The priming score was the variable of interest. Priming effects are obtained in normal subjects and schizophrenia patients, regardless of the implicit test used. However, a dissociation in priming between normal and patient groups was observed, depending on the test used. For word fragment test, priming was identical between the two groups. However, for word production, priming obtained in schizophrenics was lower than priming in normal controls. Results confirm a dissociation effect in implicit memory tests. These results could be explained in the context of the Roediger and Blaxton (1987) distinction between data-driven and conceptually-driven processing. This evidence suggests that a complete neuropsychological assessment of memory in schizophrenia should include different kinds of implicit memory tests (procedural, perceptual, and conceptual tasks).

Polymerase Switching in DNA Replication

Our view of DNA replication has been of two coupled DNA polymerases anchored to the replication fork helicase in a "replisome" complex, synthesizing leading and lagging strands simultaneously. New evidence suggests that three DNA polymerases can be accommodated into the replisome and that polymerases and repair factors are dynamically recruited and engaged without dismantling of the replisome.

The effects of selective attention on perceptual priming and explicit recognition in children with attention deficit and normal children

Perceptual priming and recognition for attended and unattended pictures at encoding, compared to nonstudied pictures were examined in second and fifth grade schoolchildren with attention deficit (AD) and children without AD. In the study, a visual perceptual priming paradigm was combined with a selective attention procedure at encoding to look for the influence of attention in implicit and explicit memory tasks. The findings showed preserved perceptual priming for attended objects at encoding in second and fifth grade AD children and normal children but only the older children showed reduced perceptual priming for unattended pictures, a result that has been reported in adults (Ballesteros, Reales, García, & Carrasco, 2006). Overall, AD children performed more poorly in the picture fragment completion task than control children, exhibiting a general deficit in the task. The findings suggest that substantial developmental changes occurred in both groups and that attention does not dissociate performance in implicit and explicit memory tasks. The preserved perceptual priming and recognition observed in AD children indicate that they performed normally in effortless memory tasks in which stimuli remain present during testing. These results may have important practical implications as these preserved abilities may be used in the rehabilitation of these children.

The role of thought suppression in building mental blocks

This research examined the role of thought suppression in the formation of mental blocks. In Experiment 1, participants were asked to generate a series of creative associates for two target words after initially suppressing a word that was semantically related to one of the two target words. Participants produced fewer responses, and experienced a greater sensation of being mentally blocked, when attempting to produce associates for the target word that was semantically related to the suppressed word. In Experiment 2, participants either thought about or suppressed a series of words prior to completing a word fragment completion task. Each word either corresponded exactly to one of the word fragment solutions (target primes) or resembled one of the solutions but was slightly different in its orthographic properties (negative primes). Participants performed most poorly on the items for which they had initially suppressed negative primes.

Equivalent inter- and intramodality long-term priming: Evidence for a common lexicon for words seen and words heard

Weaker inter- than intramodality long-term priming of words has promoted two hypotheses: (1) separate visual and auditory lexicons and (2) modality dependence of implicit memory. In five experiments, we employed manipulations aimed to minimize study-test asymmetries between the two priming conditions. Activities at visual and auditory study were matched, words were phonologically consistent, and study modality was manipulated between subjects. Equal magnitudes of inter- and intramodality priming were found in experiments with visual and auditory stem completion at test, with visual fragment completion at test, and with visual and auditory perceptual identification at test. A within-subjects experiment yielded the conventional intramodality advantage. The results point to a single amodal lexicon and to modality-independent phonological processing as the basis of implicit word memory.

Nice wor_ if you can get the wor_: Subliminal semantic and form priming in fragment completion

Two experiments investigated subliminal semantic and form priming in a word-completion task. Visual gap-words with a dominant and a subordinate solution were preceded by form-related or by semantically related words, which were briefly presented and sandwich-masked. Priming of the subordinate solution was assessed in Experiment 1, relative to a neutral condition. Both solutions were primed in Experiment 2. In the absence of conscious prime recognition, both semantic and form primes reliably increased the probability with which the primed solution was given. With our variant of fragment-completion, response priming can be ruled out as explanation. Moreover, effects were already present at first presentation, excluding an interpretation in terms of partial awareness due to massive repetition. The data demonstrate automatic activation at both form and semantic levels in the absence of conscious awareness.

Age differences in implicit interference.

We assessed age differences in interference effects in priming by using fragment completion. In Experiment 1, noninterfering filler words preceded critical targets at study, and priming was age invariant. In Experiment 2, the same target items had interfering competitors at the beginning of the list, such that both the target and the competitor were legitimate solutions to a fragment. Having two responses to a cue was disruptive for older adults, but not for younger adults. Younger and older adults differ in their susceptibility to interference in implicit tasks, and interference may play a role in influencing the magnitude of age differences in priming.

Fragment Difficulty in Priming on Word-Completion Tests

Word-fragment completion is a frequently used test in implicit memory research. In this test priming is the relevant variable. Priming is obtained by subtracting the proportion of nonstudied word fragments correctly completed (called "completion difficulty baseline") from the studied word fragments correctly completed. Since completion difficulty can spuriously vary greatly between experimental conditions, its effect on magnitude of priming is studied. Normative frequency of occurrence of target words was considered because their influence over performance is known. In an experiment using a word-fragment completion test, participants' completion of fragments at three levels of completion difficulty and two levels of frequency was tested. Analysis showed that completion difficulty had a significant effect on global priming. The priming magnitude was higher for Difficult and Moderately Difficult fragments than for Easy ones. An interaction between fragment difficulty and normative word frequency was observed. When the fragments were easy to complete, the expected effect of higher priming for low-frequency words than for high-frequency words was not observed.

Deficient morphological processing in adults with developmental dyslexia: another barrier to efficient word recognition?

Research on dyslexia has focused on the phonological level of linguistic analysis. Here we extend the investigation of the linguistic competence of individuals with dyslexia to the morphological level of linguistic analysis. We examine whether adult Hebrew readers with dyslexia extract and represent morphemic units similarly to normal readers. Using the priming paradigm in the word fragment completion task, we measured the magnitude of morphological priming and contrasted this effect with the repetition priming effect. Students with normal reading ability showed the typical repetition priming effect. A comparable repetition priming effect was also found for the dyslexic group as a whole. However, when the dyslexics were classified into three subtypes according to their phonological and orthographic decoding skills, repetition priming effects were significant only for the phonological dyslexia subgroup but not for the surface or mixed dyslexia subgroups. Furthermore, students with normal reading ability showed strong morphological priming, comparable in strength to the repetition priming effect. In contrast, the dyslexic readers did not show morphological priming, neither the dyslexia group as a whole, nor any of the subgroups. Our results highlight an additional source for dyslexics' difficulties with word recognition which lie at the level of morphological processing.

Saturating representation of loop conformational fragments in structure databanks

BackgroundShort fragments of proteins are fundamental starting points in various structure prediction applications, such as in fragment based loop modeling methods but also in various full structure build-up procedures. The applicability and performance of these approaches depend on the availability of short fragments in structure databanks.ResultsWe studied the representation of protein loop fragments up to 14 residues in length. All possible query fragments found in sequence databases (Sequence Space) were clustered and cross referenced with available structural fragments in Protein Data Bank (Structure Space). We found that the expansion of PDB in the last few years resulted in a dense coverage of loop conformational fragments. For each loops of length 8 in the current Sequence Space there is at least one loop in Structure Space with 50% or higher sequence identity. By correlating sequence and structure clusters of loops we found that a 50% sequence identity generally guarantees structural similarity. These percentages of coverage at 50% sequence cutoff drop to 96, 94, 68, 53, 33 and 13% for loops of length 9, 10, 11, 12, 13, and 14, respectively. There is not a single loop in the current Sequence Space at any length up to 14 residues that is not matched with a conformational segment that shares at least 20% sequence identity. This minimum observed identity is 40% for loops of 12 residues or shorter and is as high as 50% for 10 residue or shorter loops. We also assessed the impact of rapidly growing sequence databanks on the estimated number of new loop conformations and found that while the number of sequentially unique sequence segments increased about six folds during the last five years there are almost no unique conformational segments among these up to 12 residues long fragments.ConclusionThe results suggest that fragment based prediction approaches are not limited any more by the completeness of fragments in databanks but rather by the effective scoring and search algorithms to locate them. The current favorable coverage and trends observed will be further accentuated with the progress of Protein Structure Initiative that targets new protein folds and ultimately aims at providing an exhaustive coverage of the structure space.

Retrieval-induced forgetting in perceptually driven memory tests.

Recent data (T. J. Perfect, C. J. A. Moulin, M. A. Conway, & E. Perry, 2002) have suggested that retrieval-induced forgetting (RIF) depends on conceptual memory because the effect is not found in perceptually driven tasks. In 3 experiments, the authors aimed to show that the presence of RIF depends on whether the procedure induces appropriate transfer between representations and competition rather than on the nature of the final test. The authors adapted the standard paradigm to introduce lexical categories (words that shared the first 2 letters) at study and practice. Direct and indirect fragment completion tests were used at retrieval. The results showed significant RIF effects in perceptually driven tasks. Furthermore, they indicated that the presence of RIF effects depended on using adequate cuing to induce competition during the retrieval practice and on the final memory test tapping the inhibited representation.

A mixed-handed advantage in episodic memory: A possible role of interhemispheric interaction

Recent behavioral and brain imaging data indicate that performance on explicit tests of episodic memory is associated with interaction between the left and right cerebral hemispheres, in contrast with the unihemispheric basis for implicit tests of memory. In the present work, individual differences in strength of personal handedness were used as markers for differences in hemispheric communication, with mixed-handers inferred to have increased interhemispheric interaction relative to strong right-handers. In Experiment 1, memory for words was assessed via recall or word fragment completion. In Experiment 2, memory for real-world events was assessed via recall. Results supported the hypothesis, in that mixed-handers displayed better episodic memory in comparison with strong right-handers.

The locus and time course of long-term morphological priming

Two experiments investigated the effects of long-term morphological priming in the fragment completion task. Completions for some of the fragments were presented visually during a preceding task, and others were presented auditorily. In addition, some of the target completions were morphologically related to words that were presented visually during the study task, while still others were unrelated to any of the study words. Fragments were most likely to be completed if either the completion or one of its morphological relatives was presented visually during the study task. Analyses of response latencies also indicated that the time course of morphological priming was similar to that of visual identity priming and that both morphological and visual identity priming had earlier influences than auditory identity priming. Overall, the results indicate that morphological priming includes a modality-specific component that reflects the operation of processes that occur relatively early in the time course of processing.