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This experiment studies French-speaking adults' preferences for prosodic marking (focal accent) or morphosyntactic marking (clefting) to express information contrasts in dialogue. Our goal is to determine what syntactic and conceptual factors might contribute to these preferences, by examining for the former, the grammatical function of the item bearing the contrastive mark (subject vs complement) and, for the latter, the size of the class to which the contrasted item belongs (two members vs more than two members). The subjects' responses on a forced-choice judgment task showed that when only one device was used for contrast, subjects clearly preferred clefting for grammatical subjects and focal accent for complements. When both devices were used (prosodic and morphosyntactic), contrasted subjects were preferred over contrasted complements. Response times were longer when the contrasted item belonged to a two-member class. These results demonstrate that subjects' judgments of the suitability of linguistic devices for expressing information contrasts in French are more highly affected by syntactic factors than conceptual ones.  相似文献   
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Visual pop-out occurs when a unique visual target (e.g., a feature singleton) is present in a set of homogeneous distractors. However, the role of visual awareness in this process remains unclear. In the experiments reported here, we showed that even though subjects were not aware of a suppressed pop-out display, their subsequent performance on an orientation-discrimination task was significantly better at the pop-out location than at a control location. These results indicate that conscious visual awareness of a feature singleton is not necessary for it to attract attention. Furthermore, the subliminal pop-out effect disappeared when subjects diverted their attention toward a rapid sequential visual presentation task while presented with the same subliminal pop-out display. These results suggest that top-down attention is necessary for the subliminal pop-out effect and that the cognitive processes underlying attention and awareness are somewhat independent.  相似文献   
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Learning impairments and the instability of memory are defining characteristics of cognitive aging. However, it is unclear if deficits in the expression of new memories reflect an accelerated decay of the target memory or a consequence of inefficient learning. Here, aged mice (19–21-mo old) exhibited acquisition deficits (relative to 3–5-mo old mice) on three learning tasks, although these deficits were overcome with additional training. When tested after a 30-d retention interval, the performance of aged animals was impaired if initial learning had been incomplete. However, if trained to equivalent levels of competence, aged animals exhibited no retention deficits relative to their young counterparts. These results suggest that age-related “memory” impairments can be overcome through a more effective learning regimen.Aging is associated with broad deficits in the acquisition of new knowledge (Matzel et al. 2008; see, for review, Gallagher and Rapp 1997; Rosenzweig and Barnes 2003), as well as impairments in the retrieval of both old and newly acquired information. While it is clear that old memories (i.e., ones obtained prior to age-related cognitive declines) do in fact become less stable with age (Gallagher 1997), it is less clear whether newly attained memories are inherently less stable in aged animals, or whether age-related memory deficits reflect a secondary consequence of inefficient learning.The majority of published data regarding cognitive aging describes impairments of animals'' learning abilities (Gage and Dunnett 1984; Markowska et al. 1994; Meliska et al. 1997; Nalbantoglu et al. 1997; Vogel et al. 2002; Matzel et al. 2008), although a smaller percentage of these studies also report animals'' performances after long retention intervals. Of those studies that report retention deficits, in most of those studies the initial learning upon which the long-term memory was based was impaired relative to young animals (e.g., Barnes and McNaughton 1985; Kinney et al. 2001a,b; Gould and Feiro 2005). Interestingly, in those few studies in which initial learning was equated across young and old animals, including studies of spatial water maze performance and appetitive instrumental responding, no retention deficits were observed, even after retention intervals as long as 21 d (Soffie and Lejeune 1991; Martinez-Serrano et al. 1996; Port et al. 1996).Although suggestive, the above experiments were not systematically designed to assess the stability of memory in aged animals as a function of the level of initial learning. In the present study, young (3–5 mo) and old (19–21 mo) male Balb/C mice were trained in three learning tasks (a spatial water maze, an egocentric Lashley III maze, and a three-choice odor discrimination). When trained to pre-asymptotic levels, aged animals exhibited both learning and retention deficits (assessed 30 d after initial training). However, when aged animals were trained to levels of competence comparable to their young counterparts, both young and old animals exhibited statistically indistinguishable levels of retention.Sixty Balb/C mice arrived in our laboratory at 2.5 mo (n = 30) or 18.5 mo (n = 30) of age. Each age category was divided into two groups of 15, one of which would receive subasymptotic training on each of the three learning tasks, and one of which would receive extended training on those tasks. Two aged mice became ill during the course of testing and were excluded from all analyses. Young mice ranged from 19.8 to 29.1 g, and aged mice from 26.2 to 37.3 g. Maintenance, food deprivation, and training conditions were as previously described (Matzel et al. 2006, 2003). Behavioral testing of young and aged mice was concluded at ∼5 and 21 mo of age, respectively.All animals were tested in three independent learning tasks. Briefly, the spatial water maze encourages mice to integrate spatial information to efficiently escape from a pool of water. In odor discrimination, animals must use a target odor (from a group of three odors) to guide their search for food. In the Lashley III maze, animals learn an egocentric sequence of turns to obtain a food reinforcer. Training on each task required 2–10 d (depending on the task and the level of training), and animals received four days of rest between tasks. A retention test was administered 30 d after the last training trial of each task.A Lashley III maze was constructed from black Plexiglas. A 3-cm-diameter white disk was located in the center of the goal box, and a 45 mg Bio-Serv food pellet (dustless rodent grain) was placed at the center of the disk and served as the reinforcer. Food-deprived animals received a day of acclimation to the maze, followed by either one or two days of training (four trials/day). On the day prior to the acclimation, animals received three Bio-Serv pellets in their home cage (thus mitigating any neophobia to the food on subsequent exposures). On the acclimation day, each mouse was confined in each of the first three alleys of the maze for 4 min, and in the final alley (containing the goal box) for 6 min. On this acclimation day, three Bio-Serv pellets were placed in the goal box. On the subsequent training day(s), each animal was placed in the start box and allowed to freely navigate the maze, during which time the number of errors to reach the goal box were recorded. (An error was constituted by a turn in the wrong direction or a retracing of a previously completed path.) Upon consuming the food pellet, the animal was returned to its home cage for a 25-min intertrial interval (ITI). All animals completed four trials during the first training day. Half of those animals then received an additional four training trials on the following day. Twenty-nine days after the last training trial, all animals received three Bio-Serv pellets in their home cages, and on the subsequent day were again tested in the maze.For the water maze, a round pool (140 cm diameter, 56 cm deep) was filled to within 20 cm of the top with water that was clouded with a water soluble black paint. A hidden 14-cm-diameter black platform was located in a fixed position 1 cm below the surface of the water. The pool was enclosed by a ceiling high black curtain on which five different light patterns (which served as spatial cues) were fixed at various positions. These light cues provided the only illumination of the maze, which was 60 Lux at the water''s surface.On the day prior to training, each animal was confined for 360 sec to the platform by a clear Plexiglas cylinder that fits around the platform. For either one or two training days (six trials Day 1, five trials Day 2), the animals were started from one of three positions, such that no consecutive trials started from the same position. After locating the platform or swimming for 90 sec, the animals were left or placed on the platform for 10 sec, after which they were placed in a holding box (for 12 min) before the start of the next trial. After the sixth or 11th training trial, animals were returned to their home cages for 3 h, and were then administered a 30-sec “probe” test in which the escape platform was removed from the maze and the time spent searching in the target quadrant was recorded. One hour later each animal received an additional training trial (intended to re-establish the search strategy employed by the animal prior to the probe test). Animals were then returned to their home cages, where a 30-d retention interval began.In odor discrimination, mice navigate through a field using unique odors to guide them. The animals learn to choose the food cup that contains the target smell when given three choices. The food cup locations are rearranged on each trial, but the accessible food is always marked by the same target odor (in this case mint). The chamber consisted of a black Plexiglas 60-cm-square field with 30-cm-high walls, which was located in a dimly lit room with high ventilation. A food cup was located in three corners. The target cup had accessible food (30 mg of chocolate puffed rice), while the remaining cups contained food that could not be accessed. A cotton tipped swab (2-cm long) was loaded with 25 μL of lemon-, mint- (the target odor), or almond-flavored extract and extended vertically from the back corner of each cup.Each animal had one day of acclimation and one day of training (consisting of four training trials). (In this task, both young and old animals reached asymptotic levels of performance [near errorless] within four training trials.) On Day 1 (adaptation), each mouse was placed in the box for 20 min with no food cups present. On the subsequent training day, a food cup was placed in three corners of the field, but only the cup associated with the mint odor contained accessible food. Each animal received four trials in which they were placed in the corner of the training chamber that did not contain a food cup. A trial continued until the animal obtained the food from the target location, at which time the animal was returned to its home cage to begin a 20 min ITI. At the end of each trial the food cups were rearranged, but mint always remained as the target odor. For each trial, the number of errors (contact with or sniffing within 2 cm of an incorrect food cup) was recorded. After the fourth training trial, the animal was returned to its home cage for a 30-d retention interval. On the 29th retention day, all animals received three pieces of chocolate flavored rice in their home cages, and on the subsequent day were again tested as in original training.  相似文献   
4.
The contents of working memory (WM) have predominantly been viewed as necessarily conscious. However, recent findings suggest otherwise. Here we investigate whether visual WM can represent subliminal stimuli, such that the positions of an invisible moving object can be extrapolated or learned about in terms of their task-relevant predictive power. We presented a moving cue subliminally and measured subjects' performance on an orientation-discrimination task at the naturally anticipated location on the cue's trajectory and at variably predictable off-trajectory locations. Our data show that orientation discriminability at the on-trajectory location was not significantly different from that at a nearby off-trajectory location. However, orientation discriminability at locations near the final position of the cue was significantly better than that at distal locations. This finding suggests that a moving object can still attract attention when presented subliminally. In contrast, the dynamic trajectory of the object and its task-relevant predictive patterns may not be monitored and maintained in visual WM. (PsycINFO Database Record (c) 2012 APA, all rights reserved).  相似文献   
5.
A retinally stabilized object readily undergoes perceptual fading and disappears from consciousness. This startling phenomenon is commonly believed to arise from local bottom-up sensory adaptation to edge information that occurs early in the visual pathway, such as in the lateral geniculate nucleus of the thalamus or retinal ganglion cells. Here we use random dot stereograms to generate perceivable contours or shapes that are not present on the retina and ask whether perceptual fading occurs for such "cortical" contours. Our results show that perceptual fading occurs for "cortical" contours and that the time a contour requires to fade increases as a function of its size, suggesting that retinal adaptation is not necessary for the phenomenon and that perceptual fading may be based in the cortex.  相似文献   
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It was formerly demonstrated that virtually all reasonable exhaustive serial models, and a more constrained set of exhaustive parallel models, cannot predict critical effects associated with self-terminating models. The present investigation greatly generalizes the parallel class of models covered by similar "impossibility" theorems. Specifically, we prove that if an exhaustive parallel model is not super capacity, and if targets are processed at least as fast as non-targets, then it cannot predict such (self-terminating) effects. Such effects are ubiquitous in the experimental literature, offering strong confirmation for self-terminating processing. Copyright 1997 Academic Press. Copyright 1997 Academic Press  相似文献   
9.
This study looks at how coreference is expressed under various oral production conditions and at various stages of development. Seven- to 11-year-old children and adults told silent comic strip stories involving two characters to a same-age peer. The stories varied as to: (1) the frame presentation mode, (2) the links between events across frames, and (3) thematic continuity. The results showed that, (1) in general, all speakers marked increasing referent givenness (the 7-year-olds and adults less so than the 11-year-olds), (2) arbitrarily placed picture sequences led to a greater number of markers of increasing referent givenness than ordered sequences (which made it easier to put the information into story format), and (3) speakers were more inclined to tell the story when the frames were shown all at once (on the same page) than when they were presented in booklet format (one frame per page). The manipulation of the production conditions turned out to be an effective way of revealing speaker competence. In step-by-step encoding where the pictures were discovered one at a time, 7-year-old children exhibited a greater tendency to describe each frame as an independent entity, 11-year-old children always marked increasing referent givenness, and adults maintained coreference in a more flexible manner by varying the markers used to express referent givenness. The viewing of all frames at once before encoding provided support for the expression of emerging narrative skills. This condition enabled the 7-year-olds to no longer describe the pictures independently, promoted the marking of increasing referent givenness between the ages of 7 and 9, and pointed out the age (9 years) when the speakers began to mark coreference as a function of how the story ended.  相似文献   
10.
Linguistic studies of the intonation of Yes–No questions in French show that, in questions containing more than two stress groups, interrogative intonation is characterized by a sequence of lowered pitches or downstepped tones which precede the final rise. The gating paradigm was used here to determine whether subjects listening to French NP utterances containing three stress groups could indicate whether the utterance was an statement or a question before the final rise was heard. Although the task was difficult, findings indicate that listeners can in fact to a certain extent, recognize with mid confidence ratings, the intonational device of a question while they were hearing the downstepped tones preceding the final rise.  相似文献   
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