bluuebunny/crossref_metadata_2025 huggingface dataset:
Amnesics Have a Disproportionately Severe Memopry Deficit for Interactive Context
Authors: Mayes Andrew R. , MacDonald Chris , Donlan Lesley , Pears Julian , Meudell Peter R.
Published: September 2011

Two experiments were used to compare the recognition memory of amnesic and normal subjects for intentionally encoded words (targets) and for incidentally encoded words that were meaningfully related to the targets and presented at the same time (interactive context). In both experiments the target recognition of the two groups was matched at a high level by presenting the amnesics with much shorter lists of words to remember. Experiment 1 compared 20 amnesics and their matched controls and showed that whereas the amnesics' recognition of the target words did not benefit significantly when they were presented together with their interactive context words (relative to their recognition when the target words were presented alone), that of the controls did. Experiment 2 compared 14 amnesics and their matched controls and showed that when patients and their controls were matched on their target word recognition in isolation, then the patients still showed worse recognition for the interactive context words. These effects were not found only in Korsakoff patients, and their size did not correlate with behavioural measures of frontal-lobe damage. It is concluded that amnesics may be more impaired at recognizing incidentally encoded interactive context than they are at recognizing target material, and this deficit may be an essential feature of the syndrome.
Attentional Modulation of Size Contrast
Authors: Shulman Gordon L.
Published: September 2011

A test circle surrounded by smaller context circles appears larger if presented in isolation, whereas a test circle surrounded by large context circles is seen as smaller than in isolation. Two experiments are reported indicating that this phenomenon, the Ebbinghaus illusion, depends on whether subjects are attending to the context circles. Subjects first saw a reference circle and then a briefly presented (150 msec) test circle. Their task was to determine whether the test circle was larger or smaller than the reference. The test circle was surrounded by smaller context circles of one colour arrayed along a horizontal axis centred on the test, and larger context circles of a different colour arrayed along a vertical axis centred on the test. Subjects judged both the size of the test and the colours of either the small or large context circles. Perceived test size changed systematically, depending on which context circles were task-relevant.
Relative Effectiveness of Central, Peripheral, and Abrupt-onset Cues in Visual Attention
Authors: Koshino Hideya , Warner Bruce C. , Juola James F.
Published: September 2011

The relative effectiveness of central arrow, peripheral arrow, and abrupt-onset cues was assessed in a character recognition task. On each trial, either a central or a peripheral arrow cue was presented 0, 100, or 200 msec before the appearance of a three-digit display. Two of the digits were “uncamouflaged” from previous figure-eight masks, whereas the third digit appeared abruptly in a previously empty space. Four different groups of subjects were run in factorial combinations of high or low expected validities for arrow and onset cues. In Experiment 1, arrow cues were located centrally, near the fixation point. Abrupt onsets showed larger cost-plus benefits than central arrows, except when subjects expected the central cues to have higher validity than the onsets. In Experiment 2, arrow cues were located peripherally, near the display digits, and abrupt onsets were again more effective in capturing attention except when peripheral cues had higher validity and led the onsets by 100 msec or more. In both experiments, the relative effectiveness of abrupt onsets decreased with arrow SOA. The results were consistent with a model in which automatic and voluntary processes interact in their control of attentional resources.
Responding to Feedback after Multiple-choice Answers: The Influence of Response Confidence
Authors: Stock William A. , Kulhavy Raymond W. , Pridemore Doris R. , Krug Damon
Published: September 2011

A model is proposed that describes how people choose multiple-choice answers and deal with subsequent feedback. Central to the model is the construct of likelihood, a signal that: (1) indexes the match between task demands and what is known, (2) gives a basis for decisions, and (3) is estimated by response confidence ratings. In two experiments, subjects answered an item, rated confidence, and studied feedback (for 100 items), and then answered the items again. All predictions of the model were confirmed. Specifically, for right/wrong feedback messages, feedback study intervals were longer after correct than incorrect choices (for correct choices, these intervals decreased as confidence increased). Also, there was no relation between the probability of correcting errors and level of confidence. For feedback messages that consisted of an item with correct alternative marked, there was a positive relation between probability of correcting errors and level of confidence.
Evaluating Negative Tests and Refutations in a Rule Discovery Task
Authors: Kareev Yaakov , Halberstadt Naftali
Published: September 2011

Subjects participating in Wason's rule discovery task (1960) overwhelmingly try to confirm rather than refute their currently held hypothesis. Such a strategy is often inadequate and runs counter to the canons of scientific methodology. The present study was designed to investigate subjects’ differential evaluation of test strategies and outcome. One-hundred and sixty students participated in two experiments in which they had to judge someone else's potential test items in Wason's task. Experiment 1 demonstrated that exposure to various histories has a mediating effect on the strength of the confirmation bias. In Experiment 2, subjects knew the researcher's rule and thus whether each proposed test item would lead to confirmation or refutation of the hypothesis under consideration. The preferred items were those that alerted the subject to an incorrect hypothesis (refutation) and those that turned out to be positive instances of the rule sought after, with the combination of the two (a negative test leading to refutation) being most highly evaluated.
Improving Performance and Increasing the Use of Non-Positive Testing in a Rule-Discovery Task
Authors: Kareev Yaakov , Halberstadt Naftali , Shafir Dorit
Published: September 2011

A well-documented characteristic of rule discovery behaviour is subjects’ infrequent use of negative testing. Previous attempts at increasing the use of negative testing have met with little success. In an evaluation task, we found that subjects appreciate the benefits of negative testing and disconfirmation (Kareev & Halberstadt, this issue). Further, when given the choice, subjects prefer to begin their inquiry by employing a reception mode of inquiry, and only later switch to a generative strategy (Halberstadt & Kareev, 1992). In the present study we had subjects solve two rule-discovery problems. For the training problem, 180 subjects were assigned either to the traditional generation mode, in which subjects had to generate number triplets, or to a reception mode, in which subjects were presented with number triplets by the experimenter. For the subsequent test problem both groups used the traditional generation mode. Results revealed that subjects trained by the reception mode were more likely to use non-positive tests and more likely to solve the second problem. Apparently, training under the less demanding reception mode enabled subjects to realize the potential relevance of nonpositive testing.
Hypothesis-Testing Strategies: Why two Goals are Better than One
Authors: Wharton Charles M. , Cheng Patricia W. , Wickens Thomas D.
Published: September 2011

An intriguing finding in the hypothesis-testing literature concerns a large increase in the proportion of subjects who discover a rule when they are asked to determine two rules rather than that rule alone. This finding is based on Wason's (1960) “2 4 6” task, in which subjects try to discover a rule (ascending numbers) by generating and testing number triples. They are initially given an example (“2, 4, 6”) of the rule that leads to overly specific hypotheses. With single-goal (SG) instructions, subjects try to discover the correct rule and are told whether each triple proposed fits the rule. With dual-goal (DG) instructions, correct and incorrect categories are labelled, respectively, as DAX and MED. Subjects try to discover both rules and are told whether each proposed triple is DAX or MED. Two explanations of why DG subjects do better at rule discovery than SG subjects are tested: the quantity of information and the testing of complementary rules using the prevalent positive-test strategy. Results support the latter explanation: DG subjects outperform SG subjects only if they know the rules are complementary, and that SG subjects’ performance does not improve when required to test more triples before announcing their first rule. A third explanation, the positivity of the linguistic label of the feedback, is ruled out. Understanding the superiority of DG instructions might suggest a general method for enhancing rule discovery.
Orthographic Rime Priming
Authors: Bowey Judith A.
Published: September 2011

Three experiments are described, each using a partial priming technique in which a target word was briefly preceded by a masked trigram. The relative strength of priming effects was assessed by comparing the difference in target word naming times between unprimed and primed trials in different priming conditions. Experiment 1 replicated previous work in demonstrating stronger priming when the target word was primed by the orthographic rime than when the prime constituted otherwise comparable word-final trigrams that do not constitute orthographic rimes. Experiment 2 compared orthographic, phonological rime, and control primes. Only orthographic rime primes reliably increased target word naming speed, although the priming effect was less selective with longer prime durations. In Experiment 3 priming was observed for both orthographic rime and phonological rime primes shown for 150 msec. However, stronger priming was observed with orthographic rime primes. These experiments demonstrate that orthographic rime priming effects do not simply reflect the activation of an intact subunit of the target word articulation program.
Effects of Reinforcer Value on Sensitivity to Non-Verbal Operant Contingencies in Humans
Authors: Svartdal Frode , Mortensen Tord
Published: September 2011

The present experiment investigated effects of reinforcer value on sensitivity to operant force contingencies in humans. Subjects were exposed to non-salient, non-verbal operant contingencies with feedback stimuli of either low or high motivational value. Subjects who received feedback stimuli with back-up reinforcers of high motivational value demonstrated reliable adjustment to the arranged force contingencies, whereas force changes in subjects receiving low motivational feedback stimuli were unreliable. In accordance with standard animal findings, these results indicate that reinforcer value may affect operant conditioning in humans, but its effects are hypothesized to be confined to conditioning that is not mediated verbally.
Saccadic Eye Movements and Dual-Task Interference
Authors: Pashler Harold , Carrier Mark , Hoffman James
Published: September 2011

Four dual-task experiments required a speeded manual choice response to a tone in a close temporal proximity to a saccadic eye movement task. In Experiment 1, subjects made a saccade towards a single transient; in Experiment 2, a red and a green colour patch were presented to left and right, and the saccade was to which ever patch was the pre-specified target colour. There was some slowing of the eye movement, but neither task combination showed typical dual-task interference (the “psychological refractory effect”). However, more interference was observed when the direction of the saccade depended on whether a central colour patch was red or green, or when the saccade was directed towards the numerically higher of two large digits presented to the left and the right. Experiment 5 examined a vocal second task, for comparison. The findings might reflect the fact that eye movements can be directed by two separate brain systems–-the superior colliculus and the frontal eye fields; commands from the latter but not the former may be delayed by simultaneous unrelated sensorimotor tasks.
Combining Letter-Matching and Tone Discrimination: Evidence of Automatic Perceptual and Spatial Congruity Effects
Authors: Page Duane J. , Ells Jerry G.
Published: September 2011

Dual task and priming paradigms were combined to investigate the distinction between automatic and attentional processes. Subjects in two experiments performed a primed letter-matching and a tone discrimination task separately and concurrently. The interval between prime onset and letter pair (SOA) was varied from 50 to 500 msec. Cost-benefit analyses in Experiment 1 indicated that primes that matched target letter pairs began to facilitate performance at an SOA of 150 msec. Primes inhibited performance when they mismatched identical letter pairs at SOA 100. In the dual-task situation, the benefits of priming letter targets were reflected in probe latencies with no evidence of concurrent costs in tone latencies. Experiment 2 revealed that two tasks could be primed simultaneously as effectively as when each was primed alone. Findings are discussed in reference to Posner and Snyder's (1975a, 1975b) two-process theory of priming and the applicability of a secondary task technique.
Reversing the Word-Length Effect: A Comment on Caplan, Rochon, and Waters
Authors: Baddeley Alan , Andrade Jackie
Published: September 2011

Caplan, Rochon, and Waters (1992) report a failure to observe the poorer immediate serial recall for words of longer spoken duration obtained by Baddeley, Thomson, and Buchanan (1975) and subsequently replicated by others. Indeed, they find a significant reversal of this effect. We present evidence that the material used by Caplan et al. differs only minimally in spoken duration under speeded articulation conditions (Exp. 1 = 1.9%, Exp 2 = 2.31%), in contrast to a clear difference in the case of the original Baddeley et al. material (24.5%). It is further suggested that the reversal of the word-length effect may result from differences in acoustic similarity between the “long” and “short” word sets used by Caplan et al. We conclude that the evidence continues to indicate that longer spoken duration is associated with reduced memory span.
The Attentional Cost of Amplitude and Directional Requirements When Pointing to Targets
Authors: Fleury Michelle , Bard Chantal , Audiffren Michel , Teasdale Normand , Blouin Jean
Published: September 2011

The aim of this study was to investigate the comparative cost of accuracy constraints in direction or amplitude for movement regulation. The attentional cost is operationally defined as the amount of disturbance created in a secondary task by the simultaneous execution of a pointing task in direction or amplitude. The cost is expressed in terms of modifications in response to a secondary task, consisting of a foot-pedal release in response to an auditory stimulus (probe). The probe was introduced during the programming portion or the first, middle, or last portion of the pointing movement. The independent variables were the requirements of the task: direction or amplitude, and the moments of occurrence of the probe. Subjects were submitted to eight experimental conditions: (1) simple foot reaction time to a buzzer; (2) single directional task; (3) single amplitude task; (4) dual directional task (i.e. directional task with probe); (5) dual amplitude task (i.e. amplitude task with probe); (6) retest of foot simple reaction time; (7) retest of single directional task; and (8) retest of single amplitude task. Regulation in direction was more attention-demanding than regulation in distance in terms of programming. During pointing in amplitude, probe RT increased monotonically from start to end of movement execution, whereas directional pointing did not lead to any significant probe RT changes. These results emphasize the specific attentional loads for directional and amplitude pointing tasks, hence the involvement of different central nervous system mechanisms for the programming and regulation of the directional and amplitude parameters of pointing movements.
Location Coding in Chess
Authors: Saariluoma Pertti
Published: September 2011

Whether the chunks used in memorizing chess positions are general and relatively encoded schemata or very precisely coded instances is a problem that has raised some controversy within the psychology of chess skill. As chess research has had a strong impact on expertise research, this problem is important in many areas of skills research other than chess. To resolve it, four experiments were set up. In the experiments it was shown that subjects were better at recalling correctly located non-transposed chunks than transposed chunks, which were similar in structure but incorrectly located on the chessboard. The results imply that the representation of chess-specific patterns in the memory of a chess player contains not only information about the forms of chess-specific patterns, but also about their absolute locations on the chessboard. This provides an explanation for the well-known interaction between skill and type of position and its disappearance in recent experiments by Lories and Saariluoma. It can be argued that the difficulty of recalling random positions is not chiefly caused by the total absence of chunks but by their dislocation.
A Solution to the Effect of Sample Size on Outlier Elimination
Authors: Van Selst Mark , Jolicoeur Pierre
Published: September 2011

Results from a Monte Carlo study demonstrate how a non-recursive, a simple recursive, a modified recursive, and a hybrid outlier elimination procedure are influenced by population skew and sample size. All the procedures are based on computing a mean and a standard deviation from a sample in order to determine whether an observation is an outlier. Miller (1991) showed that the estimated mean produced by the simple non-recursive procedure can be affected by sample size and that this effect can produce a bias in certain kinds of experiments. We extended this result to the other three procedures. We also create two new procedures in which the criterion used to identify outliers is adjusted as a function of sample size so as to produce results that are unaffected by sample size.
Stability from Variation: The Case of Face Recognition the M.D. Vernon Memorial Lecture
Authors: Bruce Vicki
Published: September 2011

A theme running through M.D. Vernon's discussions of visual perception was the key question of how we perceive a stable world despite continuous variation. The central problem in face identification is how we build stable representations from exemplars that vary, both rigidly and non-rigidly, from instant to instant and from encounter to encounter. Experiments reveal that people are rather poor at generalizing from one exemplar of a face to another (e.g. from one photograph to another showing a different view or expression) yet highly accurate at encoding precise details of faces within the range shown by several slightly different exemplars. Moreover, provided instructions do not encourage subjects explicitly to attend to the way that different exemplars vary, faces are retained in a way that enhances familiarity of the prototype of the set, even if this was not presented for study. It is suggested that our usual encounters with continuous variations of facial expressions, angles, and lightings provide the conditions necessary to establish stable representations of individuals within an overall category (the face) where all members share the same overall structure. These observations about face recognition would probably not have come as any great surprise to Maggie Vernon, many of whose more general observations about visual perception anticipated such conclusions.
What's Distinctive about a Distinctive Face?
Authors: Bruce Vicki , Burton Mike A. , Dench Neal
Published: September 2011

In this study we examine the relationship between objective aspects of facial appearance and facial “distinctiveness”. Specifically, we examine whether the extent to which a face deviates from “average” correlates with rated distinctiveness and measures of memorability. We find that, provided the faces are rated with hair concealed, reasonable correlations can be achieved between their physical deviation and their rated distinctiveness. More modest correlations are obtained between physical deviation and the extent to which faces are remembered, either correctly or falsely, after previous study. Furthermore, memory ratings obtained to “target” faces when they have been previously seen (i.e. “hits”) do not show the expected negative correlation with the scores obtained to the same faces when acting as distractors (i.e. “false positives”), though each correlates with rated distinctiveness. This confirms the theory of Vokey and Read (1992) that the typicality/distinctiveness dimension can be broken down into two orthogonal components: “memorability” and “context-free familiarity”.
Disruption of Memory for Lip-Read Lists by Irrelevant Speech: Further Support for the Changing State Hypothesis
Authors: Jones Dylan M.
Published: September 2011

Two experiments critically re-examine the finding of Campbell and Dodd (1984, Experiment 2), which suggests that irrelevant speech disrupts the encoding of visual material for serial recall. Support is sought for the competing view that the effect of irrelevant speech is on storage by comparing the effect of a range of acoustic conditions on memory for graphic and lip-read lists. Initially, serial short-term recall of visually presented lists was examined with irrelevant speech that was both asynchronous with the visually presented items and of varied speech content (Experiment 1a). In this experiment substantial impairments in recall of both graphic and lip-read lists were found. However, with unvarying asynchronous speech (Experiment 1b) the effect of speech was small and non-significant. Experiment 2 examined the effect of changing state and of synchrony of speech with lip movements. When conditions of synchronous and asynchronous unvarying speech were contrasted, no significant effect of synchrony or irrelevant speech was found (Experiment 2a and 2c). In contrast, when the speech was varying in content, a strong effect of irrelevant speech was found; moreover, the effect was roughly the same for synchronous and asynchronous materials (Experiment 2b). The contrast in outcome with varying and unvarying speech provides strong support for the “changing state” model of the irrelevant speech effect. Coupled with the absence of an effect of synchrony in Experiment 2, these experiments reinforce the view that disruption by irrelevant speech occurs in memory, not at encoding.
Remembering, Familiarity, and Source Monitoring
Authors: Conway Martin A. , Dewhurst Stephen A.
Published: September 2011

Two experiments investigated recollective experience in a source monitoring task. Subjects saw an array of objects and performed, watched, or imagined actions involving pairs of objects. In a subsequent recognition test, subjects indicated whether their recognition judgements were made on the basis of conscious recollective experience (“remember” responses), or on some other basis such as familiarity (“know” responses). The proportions of correct “remember” responses for both objects and actions decreased from performed, through watched, to imagined actions, whereas the proportions of correct “know” responses were uninfluenced by the source of the memories. In addition, the relationship between recollective experience and accuracy of source judgement varied across sources. Source accuracy for performed actions was obtained only in “remember” responses, whereas source accuracy for imagined actions was obtained only in “know” responses. Source accuracy for watched actions was obtained in both “remember” and “know” responses. The findings suggest that the types of memory attributes available at retrieval determine the quality of subsequent memory experience, and it is proposed that memories with strongly self-referential attributes (arising from performed actions) powerfully cue recollective experience during retrieval.
Voice-onset Time and Tone-onset Time: The Role of Criterion-setting Mechanisms in Categorical Perception
Authors: Treisman Michel , Faulkner Andrew , Naish Peter L. N. , Rosner Burton S.
Published: September 2011

Problems in modelling categorical perception (CP) and attempts to apply signal detection theory (SDT) to CP are reviewed. An approach based on SDT supplemented by a theory of criterion setting is presented. Criterion setting theory (CST) postulates mechanisms that reset the response criterion on each trial, and it accounts for sequential dependencies. A criterion setting model for discrimination is shown to fit data from the literature.

The hypothesis that “sharp” category boundaries may arise from the suppression of noise caused by intertrial dependencies was examined in an experiment on the identification of [ba] and [pa] syllables, and tone combinations of varying tone-onset time. However, it was shown that both positive and negative intertrial dependencies were present. They could be fitted by the criterion-setting model; in this respect, CP resembles standard psychophysical judgements.

Examination of the psychometric functions from the two CP tasks shows that they are not normal ogives, as in standard psychophysical tasks: these curves are steeper centrally and flatter at the extremes than a Gaussian ogive; we describe them as “hypersigmoid”. The description of CP identification functions as hypersigmoid provides a new, qualitative characterization of the “sharp” category boundaries traditionally claimed for CP. Their causation remains to be determined.
The Directed Forgetting Effect in Word-fragment Completion: An Application of the Process Dissociation Procedure
Authors: Russo Riccardo , Andrade Jackie
Published: September 2011

In three experiments, subjects were asked to remember and forget study words. In line with previous studies, a directed forgetting effect was observed in a word-fragment completion task: Instructions to remember increased the completion of target fragments compared with instructions to forget (Experiment 1). Using the process dissociation procedure (Jacoby, 1991), it appeared that instructions to remember increased the estimates of intentional influences of memory but did not affect the estimates of automatic uses of memory (Experiments 1, 2 and 3). This suggests that directed forgetting effects in word-fragment completion reflect the surreptitious influence of explicit memory in a nominally implicit memory task. However, a meta-analysis indicated that directed forgetting instructions affected automatic and intentional influences of memory in opposite directions. This finding casts doubt on the assumption of independence between automatic and intentional uses of memory. The implications for use of the process dissociation procedure are discussed.
Age Effects in the Processing of Typical and Distinctive Faces
Authors: Johnston Robert A. , Ellis Hadyn D.
Published: September 2011

Two experiments exploring the differential processing of distinctive and typical faces by adults and children are reported. Experiment 1 employed a recognition memory task. On three out of four dimensions of measurement, children of 5 years of age did not show an advantage for distinctive faces, whereas older children and adults did. In Experiment 2, however, subjects of all ages classified typical faces faster than distinctive ones in a face/non-face decision task: the 5-year-olds performed exactly as did adults and older children. The different patterns in performance between these two tasks are discussed in relation to possible cognitive architectures for the way young children represent faces in memory. Specifically, we examine two alternative architectures proposed by Ellis (1992) as precursors for Valentine's (1991a) multidimensional adult face-space and discuss whether implementations of these spaces should be based on a norm-based or an exemplar-based framework.
Deduction from Uncertain Premises
Authors: Stevenson Rosemary J. , Over David E.
Published: September 2011

We investigate how the perceived uncertainty of a conditional affects a person's choice of conclusion. We use a novel procedure to introduce uncertainty by manipulating the conditional probability of the consequent given the antecedent. In Experiment 1, we show first that subjects reduce their choice of valid conclusions when a conditional is followed by an additional premise that makes the major premise uncertain. In this we replicate Byrne (1989). These subjects choose, instead, a qualified conclusion expressing uncertainty. If subjects are given a third statement that qualifies the likelihood of the additional premise, then the uncertainty of the conclusions they choose is systematically related to the suggested uncertainty. Experiment 2 confirms these observations in problems that omit the additional premise and qualify the first premise directly. Experiment 3 shows that the qualifying statement also affects the perceived probability of the consequent given the antecedent of the conditional. Experiment 4 investigates the effect of suggested uncertainty on the fallacies and shows that increases in uncertainty reduce the number of certain conclusions that are chosen while affirming the consequent but have no effect on denying the antecedent. We discuss our results in terms of rule theories and mental models and conclude that the latter give the most natural account of our results.
Structural Constraints on the Performance of Symmetrical Bimanual Movements with Different Amplitudes
Authors: Spijkers Will , Heuer Herbert
Published: September 2011

In bimanual movements the amplitude of each hand's movement often depends on the concurrent amplitude of the other hand's movement such that both amplitudes become similar (amplitude coupling). We tested the hypothesis that the strength of amplitude coupling depends on the tempo of performance of a movement sequence, a hypothesis based on a model of bimanual coordination that holds that cross-talk occurs at the execution level as well as at the programming level. Subjects performed bimanual periodic arm movements on two digitizers. In nine conditions constant small, constant large, and alternating small and large amplitudes of each arm were orthogonally combined. Overall tempo was varied by instructing subjects to increase the tempo progressively by 10%. Clear tempo-dependent modulations of the amplitude were observed in movements with instructed constant amplitude when the other hand performed alternating amplitudes. The effect of the size of constant-amplitude movements on the mean amplitude of the other hand indicated cross-talk at the execution level. Cross-talk at the programming level was revealed by the dependence of the current amplitude on the change in the amplitude of the other hand in the preceding cycle. Finally, asymmetric cross-manual effects were observed.
Priming the Identification of Environmental Sounds
Authors: Stuart George P. , Jones Dylan M.
Published: September 2011

Three experiments were conducted using a repetition priming paradigm: Auditory word or environmental sound stimuli were identified by subjects in a pre-test phase, which was followed by a perceptual identification task using either sounds or words in the test phase. Identification of an environmental sound was facilitated by prior presentation of the same sound, but not by prior presentation of a spoken label (Experiments 1 and 2). Similarly, spoken word identification was facilitated by previous presentation of the same word, but not when the word had been used to label an environmental sound (Experiment 1). A degree of abstraction was demonstrated in Experiment 3, which revealed a facilitation effect between similar sounds produced by the same type of source. These results are discussed in terms of the Transfer Appropriate Processing, activation, and systems approaches.
An Investigation of the Contact Hypothesis of the Own-race Bias in Face Recognition
Authors: Chiroro Patrick , Valentine Tim
Published: September 2011

Although previous studies have demonstrated that faces of one's own race are recognized more accurately than are faces of other races, the theoretical basis of this effect is not clearly understood at present. The experiment reported in this paper tested the contact hypothesis of the own-race bias in face recognition using a cross-cultural design. Four groups of subjects were tested for their recognition of distinctive and typical own-race and other-race faces: (1) black Africans who had a high degree of contact with white faces, (2) black Africans who had little or no contact with white faces, (3) white Africans who had a high degree of contact with black faces, and (4) white Britons who had little contact with black faces. The results showed that although on the whole subjects recognized own-race faces more accurately and more confidently than they recognized other-race faces, the own-race bias in face recognition was significantly smaller among the high-contact subjects than it was among the low-contact subjects. Also, although high-contact black and white subjects showed significant main effects of distinctiveness in their recognition of faces of both races, low-contact black and white subjects showed significant main effects of distinctiveness only in their recognition of own-race faces. It is argued that these results support the contact hypothesis of the own-race bias in face recognition and Valentine's multidimensional space (MDS) framework of face encoding.
The Perceptual Centre of a Stimulus as the Cue for Synchronization to a Metronome: Evidence from Asynchronies
Authors: Vos Piet G. , Mates Jiří , van Kruysbergen Noud W.
Published: September 2011

In tasks where subjects are required to tap in synchrony to a sequence of evenly spaced uniform auditory stimuli (a metronome), tap onsets typically tend to anticipate the metronome's stimulus onsets. We investigated this phenomenon, called “negative asynchrony”, as a function of (1) the duration of the stimuli (1 or 2, 50, 100, and 300 msec), (2) the rise time of the stimuli (0%, 40%, and 80% of stimulus duration), and (3) the interstimulus onset interval duration (500, 700, and 900 msec). The results from three experiments with 28 different subjects showed a significant reduction of the negative asynchrony with longer stimulus durations, and the reduction was not significantly affected by the tempo of the stimulus sequence. Also, a prolongation of the rise time of the stimuli caused an analogous reduction of the negative asynchrony. Findings were taken to suggest that subjects use the perceptual centre rather than physical onset of stimulus as the cue with which to synchronize
PIDO: the primary immunodeficiency disease ontology
Authors: Adams Nico , Hoehndorf Robert , Gkoutos Georgios V. , Hansen Gesine , Hennig Christian
Published: September 2011

Motivation: Primary immunodeficiency diseases (PIDs) are Mendelian conditions of high phenotypic complexity and low incidence. They usually manifest in toddlers and infants, although they can also occur much later in life. Information about PIDs is often widely scattered throughout the clinical as well as the research literature and hard to find for both generalists as well as experienced clinicians. Semantic Web technologies coupled to clinical information systems can go some way toward addressing this problem. Ontologies are a central component of such a system, containing and centralizing knowledge about primary immunodeficiencies in both a human- and computer-comprehensible form. The development of an ontology of PIDs is therefore a central step toward developing informatics tools, which can support the clinician in the diagnosis and treatment of these diseases.

Results: We present PIDO, the primary immunodeficiency disease ontology. PIDO characterizes PIDs in terms of the phenotypes commonly observed by clinicians during a diagnosis process. Phenotype terms in PIDO are formally defined using complex definitions based on qualities, functions, processes and structures. We provide mappings to biomedical reference ontologies to ensure interoperability with ontologies in other domains. Based on PIDO, we developed the PIDFinder, an ontology-driven software prototype that can facilitate clinical decision support. PIDO connects immunological knowledge across resources within a common framework and thereby enables translational research and the development of medical applications for the domain of immunology and primary immunodeficiency diseases.

Availability: The Primary Immunodeficiency Disease Ontology is available under a Creative Commons Attribution 3.0 (CC-BY 3.0) licence at http://code.google.com/p/pido/. The most recent public release of the ontology can always be found at http://purl.org/scimantica/pido/owl/pid.owl. An instance of the PIDFinder software can be found at http://pidfinder.appspot.com

Contact:  nico.adams@csiro.au
Weakly supervised learning of information structure of scientific abstracts—is it accurate enough to benefit real-world tasks in biomedicine?
Authors: Guo Yufan , Korhonen Anna , Silins Ilona , Stenius Ulla
Published: September 2011

Motivation: Many practical tasks in biomedicine require accessing specific types of information in scientific literature; e.g. information about the methods, results or conclusions of the study in question. Several approaches have been developed to identify such information in scientific journal articles. The best of these have yielded promising results and proved useful for biomedical text mining tasks. However, relying on fully supervised machine learning (ml) and a large body of annotated data, existing approaches are expensive to develop and port to different tasks. A potential solution to this problem is to employ weakly supervised learning instead. In this article, we investigate a weakly supervised approach to identifying information structure according to a scheme called Argumentative Zoning (az). We apply four weakly supervised classifiers to biomedical abstracts and evaluate their performance both directly and in a real-life scenario in the context of cancer risk assessment.

Results: Our best weakly supervised classifier (based on the combination of active learning and self-training) performs well on the task, outperforming our best supervised classifier: it yields a high accuracy of 81% when just 10% of the labeled data is used for training. When cancer risk assessors are presented with the resulting annotated abstracts, they find relevant information in them significantly faster than when presented with unannotated abstracts. These results suggest that weakly supervised learning could be used to improve the practical usefulness of information structure for real-life tasks in biomedicine.

Availability: The annotated dataset, classifiers and the user test for cancer risk assessment are available online at http://www.cl.cam.ac.uk/~yg244/11bioinfo.html.

Contact:  anna.korhonen@cl.cam.ac.uk
Dissecting the Role of CHITINASE-LIKE1 in Nitrate-Dependent Changes in Root Architecture
Authors: Hermans Christian , Porco Silvana , Vandenbussche Filip , Gille Sascha , De Pessemier Jérôme , Van Der Straeten Dominique , Verbruggen Nathalie , Bush Daniel R.
Published: September 2011

The root phenotype of an Arabidopsis (Arabidopsis thaliana) mutant of CHITINASE-LIKE1 (CTL1), called arm (for anion-related root morphology), was previously shown to be conditional on growth on high nitrate, chloride, or sucrose. Mutants grown under restrictive conditions displayed inhibition of primary root growth, radial swelling, proliferation of lateral roots, and increased root hair density. We found here that the spatial pattern of CTL1 expression was mainly in the root and root tips during seedling development and that the protein localized to the cell wall. Fourier-transform infrared microspectroscopy of mutant root tissues indicated differences in spectra assigned to linkages in cellulose and pectin. Indeed, root cell wall polymer composition analysis revealed that the arm mutant contained less crystalline cellulose and reduced methylesterification of pectins. We also explored the implication of growth regulators on the phenotype of the mutant response to the nitrate supply. Exogenous abscisic acid application inhibited more drastically primary root growth in the arm mutant but failed to repress lateral branching compared with the wild type. Cytokinin levels were higher in the arm root, but there were no changes in mitotic activity, suggesting that cytokinin is not directly involved in the mutant phenotype. Ethylene production was higher in arm but inversely proportional to the nitrate concentration in the medium. Interestingly, eto2 and eto3 ethylene overproduction mutants mimicked some of the conditional root characteristics of the arm mutant on high nitrate. Our data suggest that ethylene may be involved in the arm mutant phenotype, albeit indirectly, rather than functioning as a primary signal.
Identification of Essential Subunits in the Plastid-Encoded RNA Polymerase Complex Reveals Building Blocks for Proper Plastid Development
Authors: Steiner Sebastian , Schröter Yvonne , Pfalz Jeannette , Pfannschmidt Thomas
Published: September 2011

The major RNA polymerase activity in mature chloroplasts is a multisubunit, Escherichia coli-like protein complex called PEP (for plastid-encoded RNA polymerase). Its subunit structure has been extensively investigated by biochemical means. Beside the “prokaryotic” subunits encoded by the plastome-located RNA polymerase genes, a number of additional nucleus-encoded subunits of eukaryotic origin have been identified in the PEP complex. These subunits appear to provide additional functions and regulation modes necessary to adapt transcription to the varying functional situations in chloroplasts. However, despite the enormous progress in genomic data and mass spectrometry techniques, it is still under debate which of these subunits belong to the core complex of PEP and which ones represent rather transient or peripheral components. Here, we present a catalog of true PEP subunits that is based on comparative analyses from biochemical purifications, protein mass spectrometry, and phenotypic analyses. We regard reproducibly identified protein subunits of the basic PEP complex as essential when the corresponding knockout mutants reveal an albino or pale-green phenotype. Our study provides a clearly defined subunit catalog of the basic PEP complex, generating the basis for a better understanding of chloroplast transcription regulation. In addition, the data support a model that links PEP complex assembly and chloroplast buildup during early seedling development in vascular plants.
Modelling the information behaviour of children and young people
Authors: Shenton Andrew K. , Hay‐Gibson Naomi V.
Published: September 2011

Purpose

This paper seeks to draw on the linguistic model of narrative recursion developed by Ochs and Capps and on data collected and analysed in previous research projects conducted by Shenton in order to synthesise a new framework that represents the information behaviour of children and young people.

Design/methodology/approach

The model of narrative recursion provides the basis of the framework proposed. However, additional, LIS‐specific details have been introduced to ensure that the reworked version represents the phenomenon of information behaviour pertaining to the young as appropriately as possible.

Findings

The individual elements within the Ochs and Capps model correspond closely to three phases typically associated with information behaviour – the emergence of an information need, information‐seeking action, and information use.

Research limitations/implications

No claim is made that the model delineates all instances of information behaviour. It ignores cases where information is acquired incidentally, where no clear goal is involved in the activity and where no enhancement of the knowledge state results, even though information has been accessed.

Practical implications

The model is sufficiently simple to be employed in information literacy sessions with secondary school pupils. It could also be extended to provide an instructional tool and is useful in highlighting various points in youngsters' information‐related action where intermediaries may help.

Originality/value

Although the adoption of ideas and frameworks from other disciplines with the aim of increasing understanding of LIS phenomena is a growing trend, the paper forms one of the first attempts to apply to information behaviour an existing model associated with linguistics.
Nutrients intake and health status of HIV/AIDS patients
Authors: Bello Temitope K. , Olayiwola Ibiyemi , Agbon Chineze
Published: September 2011

Purpose

There are no adequate records on the nutrition of the people living with HIV/AIDS in Nigeria. This paper aims to rectify this.

Design/methodology/approach

Purposive sampling technique was used to select 200 PLWHA respondents at the Federal Medical Center Idiaba, Abeokuta. A pre‐tested questionnaire was used to collect information on the subjects’ socio‐demographic characteristics and health status of respondents. A three day 24‐hour recall was used to assess the food intake of the subjects. Adequacy of nutrient intake was assessed as a percentage of the recommended dietary allowance. Packed cell volume (PCV) estimation was investigated using a sub‐sample of 100 respondents.

Findings

The values obtained were compared with WHO/UNICEF/UNU reference values. The mean PCV for the 33 men was 31.9±6.62 while the mean value for the remaining 67 females was 29.4±4.87, which was below the reference values. A positive correlation was obtained between the PCV and energy intake (r=0.528, 33; p<0.01) as well as serum iron (r=0.474; p<0.01).

Practical implications

This study suggests that a healthy diet that is adequate in terms of energy, protein, fat, and other essential nutrients should be promoted in Nigeria as a key component of positive living for people with HIV.

Originality/value

This paper may be the first to evaluate the nutrient intake and health status of HIV/AIDS patients in Abeokuta, Nigeria