69 resultados para Object Memory

em University of Queensland eSpace - Australia


Relevância:

30.00% 30.00%

Publicador:

Resumo:

While a number of studies have shown that object-extracted relative clauses are more difficult to understand than subject-extracted counterparts for second language (L2) English learners (e.g., Izumi, 2003), less is known about why this is the case and how they process these complex sentences. This exploratory study examines the potential applicability of Gibson's (1998, 2000) Syntactic Prediction Locality Theory (SPLT), a theory proposed to predict first language (L1) processing difficulty, to L2 processing and considers whether the theory might also account for the processing difficulties of subject- and object-extracted relative clauses encountered by L2 learners. Results of a self-paced reading time experiment from 15 Japanese learners of English are mainly consistent with the reading time profile predicted by the SPLT and thus suggest that the L1 processing theory might also be able to account for L2 processing difficulty.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This combined PET and ERP study was designed to identify the brain regions activated in switching and divided attention between different features of a single object using matched sensory stimuli and motor response. The ERP data have previously been reported in this journal [64]. We now present the corresponding PET data. We identified partially overlapping neural networks with paradigms requiring the switching or dividing of attention between the elements of complex visual stimuli. Regions of activation were found in the prefrontal and temporal cortices and cerebellum. Each task resulted in different prefrontal cortical regions of activation lending support to the functional subspecialisation of the prefrontal and temporal cortices being based on the cognitive operations required rather than the stimuli themselves. (C) 2003 Elsevier Science B.V. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Increasing evidence suggests a link between attention, working memory, serotonin (5-HT), and prefrontal cortex activity. In an attempt to tease out the relationship between these elements, this study tested the effects of the hallucinogenic mixed 5-HT1A/2A receptor agonist psilocybin alone and after pretreatment with the 5-HT2A antagonist ketanserin. Eight healthy human volunteers were rested on a multiple-object tracking task and spatial working memory task under the four conditions: placebo, psilocybin (215 mu g/kg), ketanserin (50 mg), and psilocybin and ketanserin. Psilocybin significantly reduced attentional tracking ability, but had no significant effect on spatial working memory, suggesting a functional dissociation between the two tasks. Pretreatment with ketanserin did not attenuate the effect of psilocybin on attentional performance, suggestinga primary involvement of the 5-HT1A receptor in the observed defecit. Based on physiological and pharmacological data,we speculate that this impaired attentional performance may reflect a reduced ability to suppress or ignore distracting stimuli rather than reduced attentional capacity. The clinical relevance of these results is also discussed.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

To investigate the stability of trace reactivation in healthy older adults, 22 older volunteers with no significant neurological history participated in a cross-modal priming task. Whilst both object relative center embedded (ORC) and object relative right branching (ORR) sentences is-ere employed, working memory load was reduced by limiting the number of wordy separating the antecedent front the gap for both sentence types. Analysis of the results did not reveal any significant trace reactivation for the ORC or ORR sentences. The results did reveal, however, a positive correlation between age and semantic printing at the pre-gap position and a negative correlation between age and semantic printing at the gap position for ORC sentences. In contrast, there was no correlation between age and priming effects for the ORR sentences. These results indicated that trace reactivation may be sensitive to a variety of age related factors, including lexical activation and working memory. The implications of these results for sentence processing in the older population arc discussed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Results of two experiments are reported that examined how people respond to rectangular targets of different sizes in simple hitting tasks. If a target moves in a straight line and a person is constrained to move along a linear track oriented perpendicular to the targetrsquos motion, then the length of the target along its direction of motion constrains the temporal accuracy and precision required to make the interception. The dimensions of the target perpendicular to its direction of motion place no constraints on performance in such a task. In contrast, if the person is not constrained to move along a straight track, the targetrsquos dimensions may constrain the spatial as well as the temporal accuracy and precision. The experiments reported here examined how people responded to targets of different vertical extent (height): the task was to strike targets that moved along a straight, horizontal path. In experiment 1 participants were constrained to move along a horizontal linear track to strike targets and so target height did not constrain performance. Target height, length and speed were co-varied. Movement time (MT) was unaffected by target height but was systematically affected by length (briefer movements to smaller targets) and speed (briefer movements to faster targets). Peak movement speed (Vmax) was influenced by all three independent variables: participants struck shorter, narrower and faster targets harder. In experiment 2, participants were constrained to move in a vertical plane normal to the targetrsquos direction of motion. In this task target height constrains the spatial accuracy required to contact the target. Three groups of eight participants struck targets of different height but of constant length and speed, hence constant temporal accuracy demand (different for each group, one group struck stationary targets = no temporal accuracy demand). On average, participants showed little or no systematic response to changes in spatial accuracy demand on any dependent measure (MT, Vmax, spatial variable error). The results are interpreted in relation to previous results on movements aimed at stationary targets in the absence of visual feedback.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The influence of temporal association on the representation and recognition of objects was investigated. Observers were shown sequences of novel faces in which the identity of the face changed as the head rotated. As a result, observers showed a tendency to treat the views as if they were of the same person. Additional experiments revealed that this was only true if the training sequences depicted head rotations rather than jumbled views; in other words, the sequence had to be spatially as well as temporally smooth. Results suggest that we are continuously associating views of objects to support later recognition, and that we do so not only on the basis of the physical similarity, but also the correlated appearance in time of the objects.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study examines the historiography of the origins of rugby league in Australia. By accepting the inclusive nature of representation of the past as found in social memory theory, a wide range of sources ranging from histories written by academics to annuals, yearbooks and newspaper books are consulted. These sources reveal that there are several competing and conflicting accounts of the emergence of rugby league in Australia. These divergent accounts are used to facilitate a discussion of the role of narrative in sport history This article argues that narrative is an integral, not optional, feature of the production of history and that the historography of the origins of rugby league highlight the problematic nature of objectivity in history and the unavoidable, impositionalist role of the historian.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In 1984, George Orwell presented the future as a dystopian vision, where everyday existence was governed and redefined by an oppressive regime. Winston Smith's daily duties at the Ministry of Truth involved the invention, rewriting and erasing of fragments of history as a means of perpetuating contentment, uniformity and control. History, as Orwell described it in the novel 'was a palimpsest, scraped clean and reinscribed exactly as often as was necessary.' More that a quarter of a century after the publication of 1984, Michel Foucault discussed the cinematic representation and misrepresentation of French history and identity in terms of what he called the manipulation of 'popular memory'. In what was tantamount to a diluted version of Orwell's palimpsestic histories, Foucault stated that 'people are not shown what they were, but what they must remember having been.' This paper will investigate notions of memory, identity and the everyday through a discussion of the community of Celebration in Florida. Conceived in the 1990s, Celebration was designed around a fictionalised representation of pre 1940s small town America, using nostalgia for a mythologised past to create a sense of comfort, community and conformity among its residents. Adapting issues raised by Orwell, Foucault and Baudrillard, this paper will discuss the way in which architecture, like film and literature, can participate in what Foucault discussed as the manipulation of popular memory, inducing and exploiting a nostalgia for an everyday past that that never really existed.

Relevância:

20.00% 20.00%

Publicador:

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Brain electrical activity related to working memory was recorded at 15 scalp electrodes during a visuospatial delayed response task. Participants (N = 18) touched the remembered position of a target on a computer screen after either a 1 or 8 sec delay. These memory trials were compared to sensory trials in which the target remained present throughout the delay and response periods. Distracter stimuli identical to the target were briefly presented during the delay on 30% of trials. Responses were less accurate in memory than sensory trials, especially after the long delay. During the delay slow potentials developed that were significantly more negative in memory than sensory trials. The difference between memory and sensory trials was greater at anterior than posterior electrodes. On trials with distracters, the slow potentials generated by memory trials showed further enhancement of negativity whereas there were minimal effects on accuracy of performance. The results provide evidence that engagement of visuospatial working memory generates slow wave negativity with a timing and distribution consistent with frontal activation. Enhanced brain activity associated with working memory is required to maintain performance in the presence of distraction. © 1997 by the Massachusetts Institute of Technology

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Baekground: Patients with schizophrenia tend to have impaired performance on tests of working memory (WM). Neurocognitive models have linked WM to certain symptoms of schizophrenia. This study aimed to assess WM in schizophrenia and mania in the acute and subacute phases of the illness and explore correlations between WM and symptom clusters. Methods: A visuo-spatial delayed response task was used to assess WM in schizophrenia (n=20), mania (n= 14) and well controls (n=20). Patients were tested during the first week of an acute admission, and subjects were retested after four weeks. WM, symptoms (PANSS, TLC) and executive ability (COWAT, Stroop, Trail Making) were assessed at both time points. Results: When assessed for overall WM errors (both sensory and memory), there was a significant group difference (F- 11.53, df 2, 40; p