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Four experiments assessed the role of reinforcement expectancies in the trial spacing effect obtained in delayed matching-to-sample by pigeons. In Experiment 1, a differential outcome (DO) group received reinforcement with a probability of 1.0 for correct comparison responses following one sample stimulus and a probability of 0.2 for correct comparison responses following the other sample stimulus. The nondifferential outcome (NDO) group received reinforcement with a probability of 0.6 for correct responses to either stimulus. While matching accuracy was higher for the DO group than for the NDO group, both groups showed an equivalent decline in accuracy as the intertriai interval (ITI) duration was decreased. However, within the DO group, ITI duration affected performance on low-probability-of-reinforcement trials but not on high-probability-of-reinforcement trials. In Experiment 2, delay interval (DI) duration was 5, 10, or 15 sec and accuracy was higher for the DO group than for the NDO group at all DI durations. In addition, accuracy decreased similarly on high- and low-probability-of-reinforcement trials for the DO group as DI was increased. In Experiment 3, all birds were studied under DO conditions and ITI duration was manipulated along with DI duration. At the short DI duration, decreasing ITI duration had a detrimental effect on low-probability-of-reinforcement trials but no effect on high-probability-of-reinforcement trials. At the long DI duration, decreasing ITI duration had detrimental effects on both types of trials. In Experiment 4, unsignaled ITI reinforcers disrupted accuracy when the DI was long and when the ITI was short. The applicability of scalar expectancy theory to these data is discussed. 相似文献
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Pigeons were trained in a within-subjects design to discriminate empty intervals (bound by two 1-sec visual markers) and filled
intervals (a continuous visual signal). The intervals were signaled by different visual stimuli and they required responses
to different sets of comparison stimuli. In Experiment 1, empty intervals were judged longer than filled intervals. The difference
between the point of subjective equality (PSE) for the empty intervals and the PSE for filled intervals increased as the magnitude
of the anchor-duration pairs increased. Although there was more pecking during filled intervals than during empty intervals,
there was no significant correlation between pecking during filled intervals and the value of the PSE. In Experiment 2, empty
intervals continued to be judged longer than filled intervals, even when pigeons were required to refrain from pecking during
filled intervals. Keypecking per se does not appear to play an important role in the empty-filled timing difference. 相似文献
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Pigeons’ memory for sequences of light flashes when gap duration is an unreliable discriminative cue
In Experiment 1, pigeons were trained with a 1-sec dark and a 1-sec houselight-illuminated delay interval to discriminate
between sequences of two and four flashes of light (feeder illumination). The sequences could be discriminated on the basis
of the number of flashes, the number of gaps, or the duration of the gap between flashes. A choose-few bias was obtained at
extended dark delays, but not at extended illuminated delays. Pigeons appeared to confuse long dark delays with the longer
gap between flashes on few-sample trials. In Experiment 2, additional sample sequences were included that made gap duration
an unreliable cue for discriminating between the few and many samples. A significant choose-many bias was obtained at extended
dark delay intervals, but no biased forgetting was found at extended illuminated delays. The pigeons appeared to discriminate
light flash sequences by relying on multiple temporal features of a sequence rather than using an event switch to count flashes.
The biased-forgetting effects observed appear to be due to instructional ambiguity that results from the similarity of the
delay interval to features of the flash sequences. nt]mis|This research was supported by Grant OGPOOD6378 from the Natural
Sciences and Engineering Research Council of Canada to A.S. 相似文献
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In Experiment 1, pigeons were trained to discriminate short (2 sec) and long (8 sec) durations of tone by responding to red and green comparison stimuli. During delay testing, a systematic response bias to the comparison stimulus correct for the long duration occurred. Tests of responding without the tone reduced accuracy on long-sample trials but not on short-sample trials suggesting that the pigeons were attending to the tone and not simply timing the total trial duration. The pigeons were then trained to match short (2 sec) and long (8 sec) durations of light to blue/yellow comparisons. During delay testing, “choose-long errors” occurred following tone durations, but “choose-short errors” occurred following light durations. In Experiment 2, accuracy was assessed on test trials in which the tone and the light signals were simultaneously presented for the same duration or for different durations. Pigeons responded accurately to durations of light, but were unable to accurately respond to durations of tone simultaneously presented with the light. The data from Experiment 1 suggest that there are important differences between light and tone signals with respect to the events that control the termination of timing. The data from Experiment 2 indicate that pigeons cannot simultaneously time visual and auditory signals independently and without interference. Consequently, they are inconsistent with the idea that there is a single internal clock that times both tone and light durations. 相似文献
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According to the mixed memory model (Penney, Gibbon, & Meck, Journal of Experimental Psychology: Human Perception and Performance, 26, 1770–1787, 2000), different clock rates for stimuli with different nontemporal properties must be stored within a single reference memory distribution in order to detect a difference between the clock rates of the different signals. In Experiment 1, pigeons were trained in a between-subjects design to discriminate empty intervals (bound by two 1-s visual markers) and filled intervals (a continuous visual signal). The intervals were signaled by different visual stimuli, and they required responses to different sets of comparison stimuli. Empty intervals were judged as being longer than filled intervals. The difference between the point of subjective equality (PSE) for the empty intervals and the PSE for the filled intervals increased proportionally as the magnitudes of the anchor duration pairs were increased from 2 and 8 s to 4 and 16 s. In Experiment 2, the pigeons were trained to discriminate intervals signaled by the absence of houselight illumination (Group Empty) or the presence of houselight illumination (Group Filled). The psychophysical timing functions for these intervals were identical to each other. The results of Experiment 1 indicate that memory mixing is not necessary for detecting a timing difference between empty and filled intervals in pigeons. The results of Experiment 2 suggest that the nature of the stimuli that signal the empty and filled intervals impacts how pigeons judge the durations of empty and filled intervals. 相似文献
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Mirco Vantaggi Angela Baldanza Alberto Renzulli Patrizia Santi Mario Luni Laura Bonomi 《Journal of Cultural Heritage》2007,8(4):434-444
Along the Umbria-Marche stretch of the Flaminia Consular Road (220 B.C.) several archaeological finds of the most important monumental works, are well preserved. The stones, employed to build many bridges, substructions and sewerages, are represented by carbonatic breccias whose geological environment of formation and source areas had never been established. On the basis of mineralogical, petrographic and micropalaeontological analyses, two groups of these lithotypes employed in Roman age were distinguished: “monogenic carbonatic breccias” only constituted by clasts of the Maiolica Unit (Late Jurassic – Early Cretaceous) and “polygenic carbonatic breccias” made of fragments (in different proportions) of Calcare Massiccio (Early Jurassic), Corniola (Early Jurassic), Maiolica (Late Jurassic – Early Cretaceous) and Scaglia Rossa (Late Cretaceous – Early Paleogene) Units. The possible source areas of the breccias are compatible with stratified slope-waste to scarp-base deposits of periglacial origin belonging to the Upper Pleistocene. In particular, among the seven investigated areas, we pointed out the most probable provenances (Monte Faeto-Colle, Costacciaro, Scirca, Foci, Secchiano) along the flanks of the Apennine Mesozoic chain of the Umbria and Marche regions. Although the Romans could have exploited the whole thickness of some outcrops (now disappeared) of these carbonatic lithotypes at the deepest part of the valleys, we have constrained a local provenance of the breccias so commonly used in the monumental works of the Flaminia. 相似文献
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Joseph B. Taylor Giampaolo Santi Stephen D. Mellalieu 《Journal of sports sciences》2016,34(20):1913-1920
Freestyle race pacing strategies (400 m) were compared between elite able-bodied swimmers and those with minimal physical (International Paralympic Committee S10 classification) and visual disabilities (International Paralympic Committee S13 classification). Data comprised 50-m lap splits and overall race times from 1176 400-m freestyle swims from World Championships, European Championships and Olympic/Paralympic Games between 2006 and 2012. Five pacing strategies were identified across groups (even, fast start, negative, parabolic and parabolic fast start), with negative and even strategies the most commonly adopted. The negative pacing strategy produced the fastest race times for all groups except for female S13 swimmers where an even strategy was most effective. Able-bodied groups swam faster than their S10 and S13 counterparts, with no differences between S10 and S13 groups. The results suggest adoption of multiple pacing strategies across groups, and even where impairments are considered minimal they are still associated with performance detriments in comparison to their able-bodied counterparts. The findings have implications for the planning and implementation of training related to pacing strategies to ensure optimal swimmer preparation for competition. Analogous performance levels in S10 and S13 swimmers also suggest a case for integrated competition of these classifications in 400-m freestyle swimming. 相似文献
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George Santi 《Educational Studies in Mathematics》2011,77(2-3):285-311
The objective of this paper is to study students?? difficulties when they have to ascribe the same meaning to different representations of the same mathematical object. We address two theoretical tools that are at the core of Radford??s cultural semiotic and Godino??s onto-semiotic approaches: objectification and the semiotic function. The analysis of a teaching experiment involving high school students working on the tangent, shows how students?? difficulties in ascribing sense to different representations of a common mathematical object can be traced back to the kind of objectification processes and semiotic functions they are able to establish. 相似文献
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Reverse image lookup technology was used to assess the users and reuses of images from the Library of Congress' Teaching with Primary Resources digital collection. After selecting 44 images for the study, researchers used Google Reverse Image Lookup to generate a dataset of over 1,400 URLs. Drawing upon a coding rubric designed for a previous study on the ultimate uses of digital library materials, researchers coded the data to identify who uses these images and for what purposes. They found that the most popular type of user was “personal,” which aligns with previous work and indicates that a pattern is emerging between ultimate use and the personal user type. Additionally, the study's results indicate that social media and popular culture research outnumbered any other type of reuse. This article introduces reverse image lookup as a viable and approachable tool for digital library assessment, and discusses its implications for assessment and content selection. 相似文献