bluuebunny/crossref_metadata_2025 huggingface dataset:
A Sensorimotor Basis for Motor Learning: Evidence Indicating Specificity of Practice
Authors: Proteau Luc , Marteniuk Ronald G. , Lévesque Line
Published: September 2011

Our previous work (Proteau, Marteniuk, Girouard, & Dugas, 1987) was concerned with determining whether with relatively extensive practice on a movement aiming task, as the skill theoretically starts becoming open-loop, there would be evidence for a decreasing emphasis on visual feedback for motor control. We eliminated vision of the moving limb after moderate and extensive practice and found that the movement became more dependent on this feedback with greater amounts of practice. In the present study, we wished to test the hypothesis, developed from our previous work, that at the base of movement learning is a sensorimotor representation that consists of integrated information from central processes and sensory feedback derived from previous experiences on the movement task. A strong test of this hypothesis would be the prediction that for an aiming task, the addition of vision, after moderate and relatively extensive practice without vision, would lead to an increasingly large movement decrement, relative to appropriate controls. We found good support for this prediction. From these and previous results, and the idea of the sensorimotor representation underlying learning, we develop the idea that learning is specific to the conditions that prevail during skill acquisition. This has implications for the ideas of generalized motor program and schema theory.
The Locus of Repetition Priming of Spoken Word Production
Authors: Wheeldon Linda R. , Monsell Stephen
Published: September 2011

Naming of a pictured object is substantially facilitated when the name has recently been produced in response to a definition or read aloud. The first experiment shows this to be so when over one hundred trials have intervened, and when the subjects can name the pictures quickly and accurately in the absence of priming. The locus of the effect must be in lexicalization processes subsequent to picture identification and is unlikely to be mediated by recovery of an episodic trace. Two further experiments show that prior production of a homophone of the object's name is not an effective prime, (although slower responses are somewhat facilitated when the homophones are spelled the same). Hence the facilitation observed for repeated production of the same word cannot be associated with the repetition of the phonological form per se. We conclude that the facilitation must be associated with retrieval of the semantic specification or the process of mapping of that specification to its associated phonological representation.
Repetition of Lexicalization across Languages: A Further Test of the Locus of Priming
Authors: Monsell S. , Matthews G. H. , Miller D.C.
Published: September 2011

Wheeldon and Monsell (this issue) found that production of a word in response to a definition had a large and long-lasting facilitatory effect on latency for later production of the same word to name a pictured object, and that this priming effect was not due to repeated production of the phonological word-form per se. This paper reports a further test of the locus of the effect. Welsh-English bilinguals named pictured objects in Welsh. Half the words were primed either by their earlier production in Welsh in response to Welsh definitions or by production of their equivalents in English in response to English definitions. Substantial facilitation resulted from prior production in the same language, none from prior production in the other language—provided that the equivalents differed in phonological form. Given that priming results neither from repeated activation of a meaning when different phonological forms are produced, nor from repetition of the same phonological form in response to different meanings, the priming effect must be localized in the connection between a word's meaning and its phonological form. We also put forward an account of bilingual lexicalization that accommodates this result together with some evidence indicating that production of words in one language is not wholly insulated from the “availability” of words in the other.
On the Relation between Time Perception and the Timing of Motor Action: Evidence for a Temporal Oscillator Controlling the Timing of Movement
Authors: Treisman Michel , Faulkner Andrew , Naish Peter L. N.
Published: September 2011

Studies of time estimation have provided evidence that human time perception is determined by an internal clock containing a temporal oscillator and have also provided estimates of the frequency of this oscillator (Treisman, Faulkner, Naish, & Brogan, 1992; Treisman & Brogan, 1992). These estimates were based on the observation that when the intervals to be estimated are accompanied by auditory clicks that recur at certain critical rates, perturbations in time estimation occur. To test the hypothesis that the mechanisms that underlie the perception of time and those that control the timing of motor performance are similar, analogous experiments were performed on motor timing, with the object of seeing whether evidence for a clock would be obtained and if so whether its properties resemble those of the time perception clock. The prediction was made that perturbations in motor timing would be seen at the same or similar critical auditory click rates. The experiments examined choice reaction time and typing. The results support the hypothesis that a temporal oscillator paces motor performance and that this oscillator is similar to the oscillator underlying time perception. They also provide an estimate of the characteristic frequency of the oscillator.
Judgements of Deontic Relevance in Reasoning: A Reply to Jackson and Griggs
Authors: Girotto Vittorio , Mazzocco Alberto , Cherubini Paolo
Published: September 2011

Facilitation on abstract versions of the selection task can be produced by deontic content. Jackson and Griggs (1990) claimed that this finding depends on the presence of an explicit negative on the not-q card. We hypothesized that the removal of the explicit negative from this card made its deontic status ambiguous. Experiment 1 demonstrated that a not-q card presenting implicit negative is not selected, and most subjects select the only card that appears to be relevant from a deontic point of view (i.e. the p card). Experiments 2 and 3 showed that the presence of the explicit negative on the not-q card is not necessary for producing facilitation, provided that the form of this card makes it clear that the not-q individual is a potential violator. Experiment 4 showed that a high success rate can be obtained even with a not-q card presenting an implicit negative. The results are discussed in terms of the specificity of reasoning in the deontic domain.
Short Report: Scrutinization, Spatial Attention, and the Spatial Programming of Saccadic Eye Movements
Authors: Findlay John M. , Kapoula Zoi
Published: September 2011

Results are presented from an experiment in which subjects’ eye movements were recorded while they carried out two visual tasks with similar material. One task was chosen to require close visual scrutiny; the second was less visually demanding. The oculomotor behaviour in the two tasks differed in three ways. (1) When scrutinizing, there was a reduction in the area of visual space over which stimulation influences saccadic eye movements. (2) When moving their eyes to targets requiring scrutiny, subjects were more likely to make a corrective saccade. (3) The duration of fixations on targets requiring scrutiny was increased. The results are discussed in relation to current theories of visual attention and the control of saccadic eye movements.
Facilitation in the Abstract Selection Task: The Effects of Attentional and Instructional Factors
Authors: Platt Richard D. , Griggs Richard A.
Published: September 2011

The present study examined performance on Wason's four-card abstract selection task. Baseline performance is very poor, usually less than 10% correct; and this task has a long record of resistance to facilitation. It was hypothesized that the two primary sources of difficulty are selective encoding of the problem information and the lack of satisfactory analytic processing. Three experiments were conducted to test this hypothesis. In Experiment 1, performance was improved by explicating the implication rule. The majority of subjects, however, still failed to make the correct selection. Subjects were required in Experiment 2 to provide reasons for their selection or non-selection of each of the cards. This response procedure, paired with an explicated rule, led to further improvements in performance (over 50% correct selections). In Experiment 3, the influence of the type of selection instruction (true-false vs. violation) was examined. Paired with an explicated rule and the reasons response format, violation instructions led to one of the highest correct selection rates ever observed for any version of the selection task: over 80% correct. Because of the importance of this result, it was replicated twice. The results of these three experiments are discussed in terms of Johnson-Laird and Byrne's mental models theory and Evans's two-stage model of reasoning.
Naming the Parents of the THOG: Mental Representation and Reasoning
Authors: Girotto Vittorio , Legrenzi Paolo
Published: September 2011

It was hypothesized that subjects misrepresent the THOG problem by confusing data and hypotheses. An abstract version of the problem in which the given exemplars and the hypothetical ones were designated by two different labels was used in three experiments. Experiment 1 showed that this version elicits a better performance than the standard version of the problem. Experiments 2 and 3 confirmed these results, by ruling out a possible alternative account of the facilitatory effect obtained in Experiment 1. The present results are discussed in relationship to the general issues of content effects and non-consequentialism in reasoning.
Parts and Wholes in Face Recognition
Authors: Tanaka James W. , Farah Martha J.
Published: September 2011

Are faces recognized using more holistic representations than other types of stimuli? Taking holistic representation to mean representation without an internal part structure, we interpret the available evidence on this issue and then design new empirical tests. Based on previous research, we reasoned that if a portion of an object corresponds to an explicitly represented part in a hierarchical visual representation, then when that portion is presented in isolation it will be identified relatively more easily than if it did not have the status of an explicitly represented part. The hypothesis that face recognition is holistic therefore predicts that a part of a face will be disproportionately more easily recognized in the whole face than as an isolated part, relative to recognition of the parts and wholes of other kinds of stimuli. This prediction was borne out in three experiments: subjects were more accurate at identifying the parts of faces, presented in the whole object, than they were at identifying the same part presented in isolation, even though both parts and wholes were tested in a forced-choice format and the whole faces differed only by one part. In contrast, three other types of stimuli–-scrambled faces, inverted faces, and houses–-did not show this advantage for part identification in whole object recognition.
Short Report: Is Spatial Information Encoded Automatically in Memory?
Authors: Andrade Jackie , Meudell Peter
Published: September 2011

A dual-task paradigm was used to test Hasher and Zacks’ (1979) hypothesis that spatial memory is automatic. Subjects saw two sets of 16 words each, the words being presented singly in random corners of a monitor screen. They were asked to remember the words and the corner in which each word was shown. In addition, subjects were given a concurrent task to perform. This task was either “easy” (counting aloud by ones) or “difficult” (counting aloud by sevens). Attention was focused either on the memory task or on the counting task. Word recognition was better when subjects carried out the easier competing counting task and when subjects concentrated mainly upon remembering the words and their positions. Contingent spatial memory was unaffected by either manipulation, supporting the hypothesis that spatial memory is automatic.
Category-Specific Impairments? No. A Critique of Sartori Et Al.
Authors: Parkin Alan J. , Stewart Fiona
Published: September 2011

In this paper we examine the claim by Sartori, Miozzo, and Job (this issue) that their patient Michelangelo exhibits a category-specific deficit in naming living things. We conclude that their data are flawed in many respects and offer no reasonable basis for the conclusions they wish to draw. In addition their further claim that the data reported by Stewart, Parkin, and Hunkin (1992) are artefactual is not supported in any substantial way by examination of the findings.
Finite-State Automata: Dynamic Task Environments in Problem-Solving Research
Authors: Buchner Axel , Funke Joachim
Published: September 2011

This paper presents a new research paradigm for analysing human learning in dynamic task environments based on the theory of finite-state automata. Some of the advantages of the approach are outlined. (1) It is possible to design classes of formally well-described dynamic task environments instead of idiosyncratic microworlds that are difficult if not impossible to compare. (2) The approach suggests assumptions about the mental representation of a discrete dynamic system. (3) The finite-state automata formalism suggests systematic and appropriate diagnostic procedures. (4) Using finite-state automata to design dynamic task environments, one does not have to give up the “ecological validity” appeal of computer-simulated scenarios.

An experiment on the utility of an external memory support system with system complexity and type of memory support as independent variables is reported to illustrate the application of the formal framework. Systematically derived dependent variables reflect both system knowledge and control performance. The results suggest that the benefits due to the availability of the external aid vary as a function of the complexity of the task. Also, using reaction time measurements, priming phenomena have been found that point to the importance of sequentiality in the representation of discrete systems. It is concluded that the approach, although not entirely new in experimental psychology, awaits further exploration in research on human learning in dynamic task environments and promises to be a stimulating paradigm for both basic and applied research.
An Examination of the Effects of Axis Foreshortening, Monocular Depth Cues, and Visual Field on Object Identification
Authors: Humphrey G. Keith , Jolicoeur Pierre
Published: September 2011

Four experiments are reported on the identification of line drawings of common objects. In each experiment, performance on “unconventional” views of the objects, in which the major axis of the object was foreshortened, was compared to performance on more “conventional” views without appreciable foreshortening. In each experiment, except Experiment 2, where performance on the two views was experimentally equated, the foreshortened views were more difficult to identify than were the conventional views. Experiments 1 and 2 showed that if the foreshortened views were presented on a background with strong monocular depth cues, object identification was improved. This result suggests that part of the difficulty in identifying objects depicted from such a view stems from an improper depth interpretation of the object depictions. Experiments 3 and 4 examined visual field differences in the identification of the two types of object view. Results reported in the neuropsychological literature have shown that people with right-hemisphere damage have particular difficulty with the identification of unconventional views of objects that foreshorten major axes. Accordingly, it was expected that there would be a left visual field advantage for the foreshortened views. Neither experiment yielded any visual field effects consistent with this expectation. Possible reasons for the lack of a field effect are discussed.
Behavioural Goals Determine Inhibitory Mechanisms of Selective Attention
Authors: Tipper Steven P. , Weaver Bruce , Houghton George
Published: September 2011

It has been argued that during selection of target objects, irrelevant distractor objects are inhibited (e.g. Tipper, 1985). This article examines whether distractor inhibition is an invariant process that occurs in the same way for each act of selection, or whether it is a flexible process that adjusts to particular behavioural goals. We review previous studies and report new experiments that demonstrate that inhibition is a flexible process. Those internal representations of the distractor that are most associated with the action to be directed toward the target are inhibited. Other properties of the ignored object can remain in an active state and can facilitate subsequent behaviour.
Attentional Bias to Threat: Roles of Trait Anxiety, Stressful Events, and Awareness
Authors: Mogg Karin , Bradley Brendan P. , Hallowell Nina
Published: September 2011

Attentional biases for threat stimuli were assessed in high and low trait anxious subjects ( n = 66) using a probe detection task. To examine the effects of trait anxiety and situational stressors, each subject was tested three times: Under no stress, laboratory-induced stress, and examination-induced stress. To evaluate the role of awareness, half the word stimuli were presented very briefly (14 msec) and masked, and the other half were presented for 500 msec without a mask. Results showed that high trait anxious subjects under exam stress showed an attentional bias towards unmasked threat stimuli compared with low trait subjects. This effect was not found under lab-induced stress, suggesting that the attentional bias for unmasked threat in high trait subjects may be a function of a prolonged stressor, rather than a transient increase in state anxiety. The results from the masked exposure condition were not predicted; high trait anxious subjects shifted attention towards the spatial location of threat words despite lack of awareness of their lexical content, but this bias was only apparent in the no-stress condition. The results are discussed in relation to recent cognitive theories of anxiety.
Word Recognition in Developmental Dyslexia: A Connectionist Interpretation
Authors: Snowling Maggie , Hulme Charles , Goulandris Nata
Published: September 2011

We present a study of the accuracy, consistency, and speed of word naming in a dyslexic boy, JM, who has severe impairments in the ability to use sub-lexical, phonological reading strategies. For words that he can recognise, JM's naming latencies do not differ from those of control subjects matched for reading age, and he is generally consistent from one occasion to the next. He can also match printed homophones with their definitions–-a skill that requires access to well-specified orthographic representations. The data are interpreted as evidence for the creation of efficient recognition devices for words within JM's sight vocabulary. However, he shows a continuing inability to use phonological decoding strategies to deal with words that he cannot recognize by sight. Overall we argue our results pose problems for stage models of reading development, and that they may best be interpreted within a connectionist framework of the development of word recognition skills.
Towards a Clarification of Spatial Processing
Authors: Quinn J.G.
Published: September 2011

Three experiments that adopt an interference paradigm to investigate characteristics of a type of movement causing interference with spatial processing are reported. Experiment 1 illustrates the importance of distinguishing between movement and attention to movement when investigating the movement characteristics of spatial processing. The technique of passive movement is used to minimize attention in the subsequent experiments. Experiment 2 confirms earlier experiments showing that passive movement causes interference in spatial processing. However, it extends the previous findings by demonstrating that passive movement is detrimental to spatial processing only when the movement is to a sequence of locations known in advance by the subjects. Experiment 3 demonstrates that the movement interference cannot be interpreted as a general interference effect but that it is selective for spatial processing. The results of these experiments permit a more precise delineation of the disruptive effects of movement in spatial processing and allow an explicit definition of spatial processing to be put forward.
Implicit and Explicit Forgetting: When is Gist Remembered?
Authors: Dorfman Jennifer , Mandler George
Published: September 2011

Recognition (YES/NO) and stem completion (cued: complete with a word from the list; and uncued: complete with the first word that comes to mind) were tested following either semantic or non-semantic processing of a categorized input list. Item/instance information was tested by contrasting target items from the input list with new items that were categorically related to them; gist/categorical information was tested by comparing target items semantically related to the input items with unrelated new items. For both recognition and stem completion, regardless of initial processing condition, item information decayed rapidly over a period of one week. Gist information was maintained over the same period when initial processing was semantic but only in the cued condition for completion. These results are discussed in terms of dual process theory, which postulates activation/integration of a representation as primarily relevant to implicit item information and elaboration of a representation as mainly relevant to semantic (i.e. categorical) information.
Age, Information Processing Speed, and Intelligence
Authors: Rabbitt Patrick , Goward Louise
Published: September 2011

Two parallel, but independent, literatures have grown out of observations that individual differences in information processing speed, as expressed in performance on choice reaction time (C RT) tasks, modestly correlate with individual differences in age and IQ test performance. These associations have prompted theories that individual differences in information processing speed functionally determine individual differences in performance of all cognitive skills by people of different general intellectual ability (Eysenck, 1986; Jensen, 1985) or age (Salthouse, 1982, 1985).

The experiments on which this literature has been based suffer from methodological weaknesses, such that comparisons have only been made very early in practice and have only concerned mean latencies for correct responses. An experiment compared 90 volunteers aged from 50 through 79 years who were grouped in terms of their performance on the AH 4 (Heim, 1968) IQ test. It explored the joint and independent effects of individual differences in age and in IQ test score and the effects of practice on mean latencies (C RTs) on the shapes of distributions of correct and incorrect responses and on the limiting speeds with which accurate responses can be made (speed/error trade-off functions). We suggest that a plausible explanation for the results is that individual differences in age and in general ability influence C RTs mainly because they affect the efficiency with which responses can be controlled to maximize speed while maintaining accuracy.
The Effects of Screen Refresh Rate on Editing Operations Using a Computer Mouse Pointing Device
Authors: Kennedy Alan , Baccino Thierry
Published: September 2011

Two experiments are described in which subjects attempted to locate a specified target word in a short text using a cursor controlled by a computer mouse pointing device. The task was performed at screen refresh rates of 50 Hz, 75 Hz, and 100 Hz. In Experiment 1, both the timing and accuracy of the cursor movement was influenced by screen pulsation. During the early phase of the movement, performance was worse at 100 Hz, whereas in the later, visually guided phase, performance was worse at 50 Hz. In Experiment 2, eye movements were recorded as the task was performed. The results show that the cursor movement is typically preceded by an eye movement and that subjects do not directly inspect the cursor in the early stages of its movement. In the later phase of the movement the cursor is tracked for considerable periods of time. The data suggest that adverse effects of screen pulsation on the control of cursor movement are inherited from penalties incurred during the process of target computation but may also be influenced by concurrent eye movements.
The Role of Task Experience and Prior Knowledge for Detecting Invalid Augmented Feedback while Learning a Motor Skill
Authors: Buekers Martinus J. , Magill Richard A.
Published: September 2011

Two hypotheses were investigated. These were generated from results reported by Buekers, Magill, and Sneyers (1994) and an uncertainty account of those and other effects on skill learning of erroneous knowledge of results (KR). The first hypothesis proposes that if experienced performers have developed the capability of detecting and correcting errors, then they should not be influenced by erroneous KR in the same way as novices. The second proposes that if information about the invalid feedback is given to subjects prior to the beginning of the practice trials, then the capability for assessing feedback can be accelerated such that subjects who receive this advance information should not be misled by the erroneous KR. The first hypothesis was investigated in Experiment 1 by having subjects practise an anticipation timing task for 450 trials. One group received correct KR on all trials, and another group received no KR. Half of the subjects in each group were unexpectedly switched to erroneous KR after 400 trials. Results indicated that the erroneous KR influenced both groups during acquisition and on a retention test one minute later. However, on a retention test given one week later, only the group that had practised with no KR before being switched to erroneous KR continued to show the negative influence of the invalid KR. The second hypothesis was examined in Experiment 2 by telling subjects prior to beginning practice trials that it was possible that the KR they received would be erroneous. Results showed that this intervention strategy was effective on the no-KR retention tests only for subjects who had no-KR trials alternated with trials on which they received the erroneous KR. The results of these experiments provide evidence that uncertainty about the validity of sensory feedback increases the likelihood that subjects will be misled by invalid augmented feedback. Moreover, this uncertainty can be overcome by increased experience or by providing advance knowledge about the nature of the invalid feedback.
Is there a Relationship between Task Demand and Storage Space in Tests of Working Memory Capacity?
Authors: Towse J.N. , Hitch G.J.
Published: September 2011

This paper considers working memory capacity, critically examining the hypothesis that counting span (the ability to count arrays of objects and store count totals) reflects a trade-off in resources available for processing and short-term storage. Previous evidence interpreted as favouring this hypothesis has confounded task difficulty with counting time. Experiment 1 validated a manipulation of the attentional demands of counting in which target objects were differentiated from non-targets by either a single feature (colour) or a feature conjunction (a combination of line orientations). The results confirmed that the two presentations involved qualitatively different attentional loads. Experiment 2 used these displays to compare counting span for children aged 6 to 11, both with and without an adjustment of target numerosity to control for differences in processing time. At all ages, span was lower when counting took longer, but there was no difference between feature and conjunction arrays once counting time was accounted for. These results argue against a resource trade-off interpretation of counting span. Rather, they support a hypothesis of resource-switching among children, implying that counting span acts as a measure of time-based forgetting.
Pragmatic Aspects of the Base-rate Fallacy
Authors: Macchi Laura
Published: September 2011

An investigation was made of the role played by verbal structure in the problems used to study the base-rate fallacy, which has traditionally been attributed to the role of heuristics (e.g. causality, specificity). It was hypothesized that elements of the verbal form of text problems led to a misunderstanding of the question or the specific information, rendering obscure the independence of the sets of data (specific information is obtained independently from the base rate). Nine texts were presented to various groups of subjects: four were taken from Tversky and Kahneman (1980) and used as controls; five were obtained by modifying the verbal form of the original in order to reveal or conceal the links between the sets of data. The percentage of base-rate fallacies was greatly reduced with texts in which the independence of the data was clear, regardless of the causality and specificity of the information they contained (which was not changed). This result suggests that there is a need to consider the rules of natural language in order to move towards a better understanding of observed phenomena.
On the Interaction of Prior Knowledge and Stimulus Structure in Category Learning
Authors: Livingston Kenneth R. , Andrews Janet K.
Published: September 2011

Contemporary theories of categorization propose that concepts are coherent in virtue of being embedded in a network of theories about the world. Those theories function to pick out some of the many possible features of a set of objects as most salient for purposes of classification, a process that is complex and still poorly understood (Murphy & Medin, 1985). Part of what makes this account incomplete is a lack of information as to (1) what makes a feature salient on a given occasion and (2) how feature salience interacts with category structure to determine the course of learning. We report on the results of three studies of category learning using complex schematic drawings to show that (1) the contrast set defined by one's initial encounters with category exemplars can be a source of individual differences in feature salience assignments; (2) such effects are short-lived in the face of clear evidence about actual feature diagnosticity; and (3) more robust prior hypotheses interact with category structure to either enhance learning or impede it. The enhancement occurs when the hypothesis emphasizes category-relevant features, even if the hypothesis is in fact incorrect. A hypothesis that assigns high salience to irrelevant features impedes learning. Learning does occur as feedback concerning category structure leads to enhanced salience for relevant features. Salience of irrelevant features remains high, however, suggesting that such learning as occurs involves augmentation and not total revision of the (incorrect) prior hypothesis.
Transitions between Modes of Inquiry in a Rule Discovery Task
Authors: Halberstadt Naftali , Kareev Yaakov
Published: September 2011

Scientists obtain their knowledge about the world through one of two major modes of inquiry—observation of naturally occurring phenomena and active experimentation. Both modes of inquiry have been extensively researched in studies of hypothesis testing behaviour and scientific inquiry, the first in studies employing the reception paradigm, the second in studies employing the selection/generation paradigm. The prevalence of both paradigms and their correspondence to well-established modes of scientific inquiry led to the hypothesis that subjects, if allowed, would employ both modes of inquiry. The variables affecting the choice of one mode rather than the other and the transitions between the two modes were expected to shed new light on the process of scientific inquiry. To test this hypothesis, 27 adults and 27 eighth-graders were set three rule-discovery problems, in a computer environment that allowed free transitions between item reception and generation. Item generation was significantly more prevalent in the adult sample, but almost all the adults and approximately half the children employed both modes of inquiry in at least one problem. When both modes of inquiry were employed, the reception mode tended to precede the generation mode. An inverse relationship was observed between item generation and the proportion of positive instances supplied by the environment. Individual inquiry styles were evident in both age groups. These results call attention to the need for a theory incorporating both modes of inquiry as integral components of the inquiry process. They also demonstrate the utility of empirical investigations that let subjects freely choose which mode to employ at any point of the inquiry process.
Consequences of a Motor Programming Deficit for Rehearsal and Written Sentence Comprehension
Authors: Martin Randi C. , Blossom-Stach Carol , Yaffee Laura S. , Wetzel W. Frederick
Published: September 2011

The role of central motor processes in rehearsal was investigated by studying a braindamaged patient with a severe articulatory impairment. Evidence is presented that his articulatory impairment is due to a disruption of motor programming rather than to peripheral muscle weakness. Despite his motor programming deficit, the patient showed normal auditory span and evidence of rehearsal for auditorily presented sequences of words. For visual presentation, span was reduced and there was no evidence of rehearsal. Also, the patient showed excellent sentence comprehension for syntactically complex sentences for both auditory and visual presentation. The results imply that central motor processes are not critical for normal short-term memory, at least for auditory presentation, and that reading comprehension does not depend on inner rehearsal.
Implicit Learning of an Invariant: Just Say No
Authors: Wright Richard L. , Burton A. Mike
Published: September 2011

Following exposure to 30 four-digit numbers containing an invariant “3”, subjects are found falsely to recognize novel four-digit numbers containing this invariant (positives) in preference to novel numbers that do not contain the invariant (negatives). Despite this false recognition, they are generally unable to report the rule relating test positives to the positives seen during the learning phase. This finding has been taken to show implicit learning of a rule. Two experiments are reported here which show that it is not necessary to learn this rule in order to perform at above-chance levels on this test. Most of the effect can be explained in terms of the rejection of particularly distinctive test items that are more prevalent in the test negatives. This rejection appears to be mediated by knowledge that is potentially explicit as opposed to implicit, and we present tentative evidence that it is rule-based as opposed to analogic.
Naming Faces: The Effects of Facial Distinctiveness and Surname Frequency
Authors: Valentine Tim , Moore Viv
Published: September 2011

The effects of the frequency of a surname in the population and of the distinctiveness of a face on the latency to name famous faces were explored. Distinctive faces were named more quickly than were typical faces. Celebrities with low-frequency surnames were named faster than celebrities with high-frequency surnames, but only if their faces were distinctive. Subsequent experiments showed that the effect of surname frequency could not be attributed to differences in the articulatory onsets of the surnames and was not present in a task that did not require a naming response. Experiments in which surnames were taught to previously unfamiliar faces showed that familiar surnames (e.g. the surnames of celebrities) were produced more rapidly than were unfamiliar surnames. If familiar surnames were taught, no effect of surname frequency was observed. It is concluded that lexical access to peoples’ names is frequency sensitive—surnames shared by few individuals are accessed faster than are high-frequency surnames. However, when learning names to unfamiliar faces, familiar surnames (i.e. the surnames of people already known to the subject) are learned and accessed more quickly than unfamiliar surnames.
Evaluating a habitat template model's predictions of marine fish diversity on the Scotian Shelf and Bay of Fundy, Northwest Atlantic
Authors: Fisher Jonathan A. D. , Frank Kenneth T. , Kostylev Vladimir E. , Shackell Nancy L. , Horsman Tracy , Hannah Charles G.
Published: September 2011

Fisher, J. A. D., Frank, K. T., Kostylev, V. E., Shackell, N. L., Horsman, T., and Hannah, C. G. 2011. Evaluating a habitat template model's predictions of marine fish diversity on the Scotian Shelf and Bay of Fundy, Northwest Atlantic. – ICES Journal of Marine Science, 68: 2096–2105. Habitat template models that integrate physical, chemical, and biological data have the potential to explain geographic variation in life-history traits within assemblages and to predict locations where species will be most vulnerable to anthropogenic impact. A previously developed model based on spatial variations in scope for growth (SG) and natural disturbance (ND) for the Scotian Shelf/Bay of Fundy was tested for its ability to predict fish life-history traits, species diversity, and community composition using trawl survey data. Of 30 dominant fish species, large, slow-growing ones most vulnerable to overexploitation tended to be found in naturally stable habitats. Among consistently co-occurring groups, functional differentiation, rather than similarity of life history, characterized assemblages, whereas among survey strata, species richness peaked at intermediate levels of ND and species evenness increased with average SG. Community composition was significantly correlated with both habitat variables, declined by 40% through time preceding structural changes on the eastern Scotian Shelf, but geographic distance, depth, and bottom temperature remained more strongly related to composition. The results revealed compelling matches between template predictions and patterns of fish species diversity, but low variation in diversity of life history, and mobility of fish may account for some of the weaker matches to model predictions.
Elstera litoralis gen. nov., sp. nov., isolated from stone biofilms of Lake Constance, Germany
Authors: Rahalkar Monali , Bahulikar Rahul A. , Deutzmann Jörg S. , Kroth Peter G. , Schink Bernhard
Published: September 2011

An alphaproteobacterium, strain Dia-1T, was isolated from algae-dominated biofilms on stones from the littoral zone of Lake Constance, Germany. This bacterium was isolated after initial enrichment in spent medium obtained after growth of a diatom culture. Numerous sugars and some organic acids and alcohols served as growth substrates. The bacterium grew slowly, was strictly aerobic but microaerophilic, and did not grow in cultures shaken under air. 16S rRNA gene sequence analysis indicated that strain Dia-1T was distantly related to representatives of the genera

Azospirillum

(90–91 % sequence similarity),

Skermanella

(88–89 %),

Rhodocista

(87–88 %) and

Dongia

(88–89 % sequence similarity). Based on this sequence comparison, on phenotypic characterization including substrate utilization patterns, and comparison of cellular fatty acids, quinones, polar lipids and polyamines, this isolate was found to be substantially different from the genera mentioned above. On the basis of these results, a novel genus and species is proposed for this strain. The name Elstera litoralis gen. nov., sp. nov. is suggested, with strain Dia-1T ( = DSM 19532T = LMG 24234T) as the type strain of the type species.
Labedaea rhizosphaerae gen. nov., sp. nov., isolated from rhizosphere soil
Authors: Lee Soon Dong
Published: September 2011

A novel actinomycete, designated strain RS-49T, was isolated from the rhizosphere soil of a cliff-associated plant (Peucedanum japonicum Thunb.) in the Republic of Korea and subjected to a polyphasic taxonomic study. The results of comparative 16S rRNA gene sequence analyses showed that the organism belonged to the family

Pseudonocardiaceae

, suborder

Pseudonocardineae

and that it was most closely related to members of the genera

Kibdelosporangium

(96.6–97.0 % sequence similarity),

Actinokineospora

(96.3–96.7 %),

Streptoalloteichus

(96.2 %) and

Actinophytocola

(96.2 %). Substrate mycelia were well-developed and whitish or pale yellow to strong yellow. Aerial mycelia were branched and fragmented into rod-shaped elements. Single spherical spores were produced directly on the substrate mycelium. Sporangium-like structures and fragmentation of the substrate mycelium were absent. The diagnostic diamino acid in the cell-wall peptidoglycan was meso-diaminopimelic acid. The acyl type of the muramic acid residues in the peptidoglycan was N-acetylated. Whole-cell sugars were glucose, rhamnose, galactose, ribose, mannose, arabinose and xylose. The major menaquinone was MK-9(H4). Small amounts of MK-8 and MK-9(H2) were also detected. The polar lipids contained diphosphatidylglycerol, phosphatidyldimethylethanolamine, phosphatidylglycerol, phosphatidylinositol, an unknown phospholipid and an unknown lipid. The predominant fatty acids were iso-C15 : 0 and iso-C16 : 0. The DNA G+C content was 64.2 mol%. The phenotypic and phylogenetic characteristics show that strain RS-49T can be differentiated from members of all genera in the suborder

Pseudonocardineae

and thus represents a novel species in a new genus for which the name Labedaea rhizosphaerae gen. nov., sp. nov. is proposed; the type strain of the type species is RS-49T ( = KCTC 19662T = DSM 45361T).
Post-transcriptional exon shuffling events in humans can be evolutionarily conserved and abundant
Authors: Al-Balool Haya H. , Weber David , Liu Yilei , Wade Mark , Guleria Kamlesh , Nam Pitsien Lang Ping , Clayton Jake , Rowe William , Coxhead Jonathan , Irving Julie , Elliott David J. , Hall Andrew G. , Santibanez-Koref Mauro , Jackson Michael S.
Published: September 2011

In silico analyses have established that transcripts from some genes can be processed into RNAs with rearranged exon order relative to genomic structure (post-transcriptional exon shuffling, or PTES). Although known to contribute to transcriptome diversity in some species, to date the structure, distribution, abundance, and functional significance of human PTES transcripts remains largely unknown. Here, using high-throughput transcriptome sequencing, we identify 205 putative human PTES products from 176 genes. We validate 72 out of 112 products analyzed using RT-PCR, and identify additional PTES products structurally related to 61% of validated targets. Sequencing of these additional products reveals GT-AG dinucleotides at >95% of the splice junctions, confirming that they are processed by the spliceosome. We show that most PTES transcripts are expressed in a wide variety of human tissues, that they can be polyadenylated, and that some are conserved in mouse. We also show that they can extend into 5′ and 3′ UTRs, consistent with formation viatrans-splicing of independent pre-mRNA molecules. Finally, we use real-time PCR to compare the abundance of PTES exon junctions relative to canonical exon junctions within the transcripts from seven genes. PTES exon junctions are present at <0.01% to >90% of the levels of canonical junctions, with transcripts fromMAN1A2,PHC3,TLE4, andCDK13exhibiting the highest levels. This is the first systematic experimental analysis of PTES in human, and it suggests both that the phenomenon is much more widespread than previously thought and that some PTES transcripts could be functional.
Tyrosine Aminotransferase Contributes to Benzylisoquinoline Alkaloid Biosynthesis in Opium Poppy
Authors: Lee Eun-Jeong , Facchini Peter J.
Published: September 2011

Tyrosine aminotransferase (TyrAT) catalyzes the transamination of l-Tyr and α-ketoglutarate, yielding 4-hydroxyphenylpyruvic acid and l-glutamate. The decarboxylation product of 4-hydroxyphenylpyruvic acid, 4-hydroxyphenylacetaldehyde, is a precursor to a large and diverse group of natural products known collectively as benzylisoquinoline alkaloids (BIAs). We have isolated and characterized a TyrAT cDNA from opium poppy (Papaver somniferum), which remains the only commercial source for several pharmaceutical BIAs, including codeine, morphine, and noscapine. TyrAT belongs to group I pyridoxal 5′-phosphate (PLP)-dependent enzymes wherein Schiff base formation occurs between PLP and a specific Lys residue. The amino acid sequence of TyrAT showed considerable homology to other putative plant TyrATs, although few of these have been functionally characterized. Purified, recombinant TyrAT displayed a molecular mass of approximately 46 kD and a substrate preference for l-Tyr and α-ketoglutarate, with apparent K  m values of 1.82 and 0.35 mm, respectively. No specific requirement for PLP was detected in vitro. Liquid chromatography-tandem mass spectrometry confirmed the conversion of l-Tyr to 4-hydroxyphenylpyruvate. TyrAT gene transcripts were most abundant in roots and stems of mature opium poppy plants. Virus-induced gene silencing was used to evaluate the contribution of TyrAT to BIA metabolism in opium poppy. TyrAT transcript levels were reduced by at least 80% in silenced plants compared with controls and showed a moderate reduction in total alkaloid content. The modest correlation between transcript levels and BIA accumulation in opium poppy supports a role for TyrAT in the generation of alkaloid precursors, but it also suggests the occurrence of other sources for 4-hydroxyphenylacetaldehyde.
An analysis of tweets in response to the death of Michael Jackson
Authors: Hoe‐Lian Goh Dion , Sian Lee Chei
Published: September 2011

Purpose

Grieving resulting from the death of a loved one or someone familiar is a painful process and individuals invariably seek support to help them through this difficult period. In this study, the paper investigates the role microblogs play by exploring the types of messages following the death of a public figure, Michael Jackson, “the King of Pop”.

Design/methodology/approach

Content analysis was conducted using 50,000 tweets harvested from Twitter from the first 12 days after Michael Jackson's death. A coding instrument characterizing a set of categories that users posted about Jackson's death was inductively constructed, and then applied to the entire dataset of tweets.

Findings

About 50 per cent of tweets fell into categories commonly associated with expressions of emotions or thoughts due to death. However, as the single largest category, Twitter was used primarily as a platform for sharing news and other information. Surprisingly, categories not normally associated with grieving, such as spreading of rumours, expressions of hatred and spam, also occupied a high proportion of tweets.

Originality/value

There has been little work done in examining microblogs as platforms for giving and receiving support in general and, more specifically, for the expression of grief. Therefore, the present research is timely, as it seeks to understand the role microblogs play in the grieving process.