Dissertations / Theses on the topic 'Discrimination learning'
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Livesey, Evan James. "Discrimination learning and stimulus representation." Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614066.
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Devalle, D. A. "Discrimination without awareness." Thesis, Bangor University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382758.
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Hyatt, Charles Winton. "Discrimination learning in the African elephant." Thesis, Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/28887.
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Walker, Jacqueline G. "Auditory discrimination learning with developmentally disabled persons." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0005/NQ41630.pdf.
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Wallace, Benjamin E. "ESSAYS ON PRICE DISCRIMINATION AND DEMAND LEARNING." UKnowledge, 2019. https://uknowledge.uky.edu/economics_etds/40.
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This dissertation consists of three essays examining how and why firms set prices in markets. In particular, this dissertation shows how firms may utilize nonlinear pricing to price discriminate, how firms may experiment with the prices they set to learn about the demand function in the market they serve in later periods and the effects of these pricing strategies on consumer welfare.
In Essay 1, I show how firms in the milk market use nonlinear price schedules -- quantity discounts -- to price discriminate and increase profits. I find that firms have a greater ability to price discriminate on their own ``private label'' products rather than regional branded that they sell alongside their own. Though some consumers benefit from a lower price as a result of the price discrimination, total consumer surplus is lower than if the store had to offer a fixed price per unit. Additionally, I compare my structural demand estimates, which using the Nielsen household panel data include consumer demographic information and actual household choices, to the standard approach in the literature on price discrimination that uses only market level data. By doing so I find that ignoring demographic information and actual consumer choices leads to biased parameter estimates. In the case of the milk market, the biased parameter estimates due to ignoring household demographic information and actual consumer choices lead to underestimating welfare harm to consumers on average.
After finding that price discrimination harms consumers overall in this market, I quantify which consumer demographic are better off and which are worse off. I find that households with children and low income households with children are the only households to benefit from the price discriminatory practices of firms in this market. Since these groups are particularly vulnerable, I suggest that policymakers take no action to correct this market, as any action will directly hurt these consumer groups.
In Essay 2, I study how firms learn about the demand in a new market by exploiting a significant change in Washington's state's liquor laws. In 2012, the state of Washington switched from a price-controlled state-store system of selling liquor to one in which private sellers could sell liquor with minimal restrictions on price and range of products. As a result, a heterogeneous group of firms entered the liquor market across the state with little knowledge of the regional demand for alcohol in the state of Washington across heterogeneous localities. Using the Nielsen retail scanner data I am able to observe the variation in pricing and offerings seasonally and over time to see if there is convergence in offerings and prices, and how quickly that convergence occurs across different localities depending on local demographics and competition. I also investigate the extent to which the variation is "experimentation'' by the firms, i.e., the firms purposely experimenting to learn more about demand and the extent that local demographics and competition can affect the experimentation and whether there are spill-overs from local competition (i.e. do firms learn from each other and does this effect how much they experiment and how quickly they learn).
My main findings are that over time, firms within this market have learned better how to price discriminate over the holiday season; firms experiment more with prices for the pint sized products than the larger sizes; and that menu of options that firms have offered has been expanding but at a slower rate, suggesting that they are approaching a long-run steady state for the optimal menu of options.
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Zhu, Beibei. "Three Essays on Employer Learning and Statistical Discrimination." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/23168.
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This dissertation consists of three essays studying employer learning and statistical discrimination of young workers in the U.S. labor market. The first chapter outlines the dissertation by discussing the motivations, methods, and research findings.Chapter two develops a framework that nests both symmetric and asymmetric employer learning, and derives testable hypotheses on racial statistical discrimination under different processes of employer learning. Testing the model with data from the NLSY79, we find that employers statistically discriminate against black workers on the basis of both education and race in the high school market where learning appears to be mostly asymmetric. In the college market, employers directly observe most parts of the productivity of potential employees and learn very little over time.
In chapter three, we investigate how the process of employer learning and statistical discrimination varies over time and across employers. The comparison between the NLSY79 and the NLSY97 cohorts reveals that employer learning and statistical discrimination has became stronger over the past decades. Using the NLSY97 data, we identify three employer- specific characteristics that influencing employer learning and statistical discrimination, the supervisor-worker race match, supervisor\'s age, and firm size. Black high school graduates face weaker employer learning and statistical discrimination if they choose to work for a black supervisor, work for an old supervisor, or work in a firm of small size.
In the last chapter, we are interested in the associations between verbal and quantitative skills and individual earnings as well as the employer learning process of these two specific types of skills. There exist significant differences in both the labor market rewards and employer learning process of verbal and quantitative skills between high school and college graduates. Verbal skills are more important than quantitative skills for high school graduates, whereas college-educated workers benefit greatly from having high quantitative skills but little from having high verbal skills. In addition, employers directly learn verbal skills and continuously learn quantitative skills in the high school market, but almost perfectly observe quantitative skills in the college market.
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Honey, R. "Conditioning and discrimination after nonreinforced stimulus preexposure." Thesis, University of York, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378062.
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Lavis, Yvonna Marie Psychology Faculty of Science UNSW. "An investigation of the mechanisms responsible for perceptual learning in humans." Publisher:University of New South Wales. Psychology, 2008. http://handle.unsw.edu.au/1959.4/42882.
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Discrimination between similar stimuli is enhanced more by intermixed pre-exposure than by blocked pre-exposure to those stimuli. The salience modulation account of this intermixed-blocked effect proposes that the unique elements of intermixed stimuli are more salient than those of blocked stimuli. The inhibition account proposes that inhibitory links between the unique elements of intermixed stimuli enhance discrimination. The current thesis evaluated the two accounts in their ability to explain this effect in humans. In Experiments 1 and 2, categorisation and same-different judgements were more accurate for intermixed than for blocked stimuli. This indicates that intermixed pre-exposure decreases generalisation and increases discriminability more than does blocked pre-exposure. In Experiments 3 ?? 5, same-different judgements were more accurate when at least one of the two stimuli was intermixed. This enhanced discrimination was not confined to two stimuli that had been directly intermixed. These results are better explained by salience modulation than by inhibition. Experiments 6 ?? 8 employed dot probe tasks, in which a grid stimulus was followed immediately by a probe. Neither intermixed nor blocked stimuli showed facilitated reaction times when the probe appeared in the location of the unique element. In Experiments 9 ?? 11 participants learned to categorise the intermixed unique elements more successfully than the blocked unique elements, but only when the unique elements were presented on a novel background during categorisation. Experiments 6 ?? 11 provide weak evidence that the intermixed unique elements are more salient than their blocked counterparts. In Experiment 12, participants were presented with the shape and location of a given unique element, and were required to select the correct colour. Performance was more accurate for intermixed than for blocked unique elements. In Experiment 13, participants learned to categorise intermixed, blocked and novel unique elements. Performance was better for intermixed than for blocked and novel unique elements, which did not differ. None of the proposed mechanisms for salience modulation anticipate these results. The intermixed-blocked effect in human perceptual learning is better explained by salience modulation than by inhibition. However, the salience modulation accounts that have been proposed received little support. An alternative account of salience modulation is considered.
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Sentís, Herrera Gael. "Dealing with ignorance: universal discrimination, learning and quantum correlations." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/134830.
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Una de las tareas fundamentales de la Teor a de la Informaci on Cu antica
consiste en identi car el estado en que ha sido preparado un sistema cu antico.
Cuando las posibles preparaciones forman una lista nita de estados, el problema
recibe el nombre de discriminaci on de estados. El caso fundamental de
unicamente dos estados posibles se conoce tambi en bajo el nombre de contraste
de hip otesis. Una de las caracter sticas distintivas de la teor a cu antica
es el hecho de que para dos estados no ortogonales no hay medida concebible
que pueda identi car el estado del sistema con certeza. El indeterminismo
cu antico exige, por tanto, un enfoque probabil stico para llevar a cabo esta
tarea. Habitualmente se considera que los estados posibles del sistema son
conocidos para el experimentador. En esta tesis analizo el papel que desempe~
na la informaci on previa disponible en la tarea de discriminaci on y, en
particular, analizo situaciones en las que dicha informaci on es incompleta.
Suponiendo una total ignorancia de la identidad de los estados posibles,
estudio la probabilidad de error de una m aquina programable de discriminaci
on para estados de qubit. Esta m aquina incorpora la informaci on sobre
los estados en forma de programas de entrada donde se introducen los sistemas
cu anticos en las diferentes preparaciones. Es decir, la informaci on
es utilizada en su forma genuinamente cu antica, en lugar de como una descripci
on cl asica de los estados. Esta ignorancia cl asica se tiene en cuenta en
el dise~no de la m aquina, la cual ya no es espec ca para cada caso, sino que es
capaz de discriminar entre cualquier par de estados de qubit, una vez ha sido
convenientemente programada mediante las entradas de estados cu anticos.
Estudio en detalle el rendimiento optimo de estas m aquinas para estados de
qubit generales cuando se dispone de un n umero de copias arbitrario, tanto
de los programas como del estado que se ha de identi car. Espec camente,
obtengo las probabilidades de correcta identi caci on en los esquemas usuales de error m nimo y discriminaci on no ambigua, as como en el esquema m as
general de discriminaci on con margen de error.
A continuaci on, este tipo de automatizaci on en tareas de discriminaci on
se lleva un paso m as all a. Entendiendo una m aquina programable como
un dispositivo entrenado con informaci on cu antica que es capaz de realizar
una tarea espec ca, propongo una m aquina de aprendizaje cu antico para
clasi car estados de qubit que no requiere una memoria cu antica para almacenar
los qubits de los programas, permitiendo as repetidos usos de la
m aquina sin necesidad de volver a entrenarla. Demuestro que dicha m aquina
de aprendizaje es capaz de clasi car el estado de un qubit con la m nima
tasa de errores admitida por la mec anica cu antica, y por tanto puede ser
reusada manteniendo un rendimiento optimo. Tambi en estudio un esquema
de aprendizaje similar para estados de luz coherente. Este se presenta en
un contexto de lectura de una memoria cl asica mediante se~nales coherentes
correlacionadas cl asicamente cuando estas son producidas por una fuente imperfecta
y, por lo tanto, en un estado con un cierto grado de incertidumbre
asociado. Muestro que la extracci on de la informaci on almacenada en la
memoria es m as e ciente si la incertidumbre se trata de una forma completamente
cu antica.
Por ultimo, analizo la estructura matem atica de las medidas cu anticas
generalizadas, omnipresentes en todos los temas tratados en esta tesis. Propongo
un algoritmo constructivo y e ciente para descomponer cualquier medida
cu antica en una combinaci on convexa estad sticamente equivalente de
medidas m as simples (extremales). Estas en principio son menos costosas de
implementar en un laboratorio y, por tanto, pueden ser utiles en situaciones
pr acticas donde a menudo prevalece una perspectiva de recursos m nimos.Discriminating the state of a quantum system among a number of options is one of the most fundamental operations in quantum information theory. A primal feature of quantum theory is that, when two possible quantum states are nonorthogonal, no conceivable measurement of the system can determine its state with certainty. Quantum indeterminism so demands a probabilistic approach to the task of discriminating between quantum states. The usual setting considers that the possible states of the system are known. In this thesis, I analyze the role of the prior information available in facing a quantum state discrimination problem, and consider scenarios where the information regarding the possible states is incomplete. In front of a complete ignorance of the possible states' identity, I discuss a quantum programmable discrimination machine for qubit states that accepts this information as input programs using a quantum encoding, rather than just as a classical description. This \classical" ignorance is taken into account in the design, and, as a consequence, the machine is not case-speci c but it is able to handle discrimination tasks between any pair of possible qubits, once conveniently programmed through quantum inputs. The optimal per- formance of programmable machines is studied in detail for general qubit states when several copies of the states are provided, in the main schemes of unambiguous and minimum-error discrimination as well as in the more general scheme of discrimination with an error margin. Then, this type of automation in discrimination tasks is taken further. By realizing a programmable machine as a device that is trained through quantum information to perform a speci c task, I propose a quantum learning machine for classifying qubit states that does not require a quantum memory to store the qubit programs. I prove that such learning machine classi es the state of a qubit with the minimum-error rate that quantum mechanics permits, thus allowing for several optimal uses of the machine without the need of retraining. A similar learning scheme is also discussed for coherent states of light. I present it in the context of the readout of a classical memory by means of classically correlated coherent signals, when these are produced by an imperfect source and hence their state has some uncertainty associated. I show that the retrieval of information stored in the memory can be carried out more accurately when fully general quantum measurements are used. Finally, I analyse the mathematical structure of generalized quantum measurements, ubiquitous in all the topics covered in this thesis. I pro- pose a constructive and e cient algorithm to decompose any given quantum measurement into a statistically equivalent convex combination of simpler (extremal) measurements, which are in principle less costly to implement in a laboratory. Being able to compute this type of measurement decomposi- tions becomes useful in practical situations, where often a minimum-resources perspective prevails.
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Quirk, Rachel Helen. "Fronto-striatal substrates of discrimination learning in the rat." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621238.
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Brackney, Ryan Vaidya Manish. "Interactions of equivalence and other behavioral relations simple successive discrimination training /." [Denton, Tex.] : University of North Texas, 2009. http://digital.library.unt.edu/ark:/67531/metadc12087.
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Adams, Gill. "Is anyone listening? : women mathematics teachers' experiences of professional learning." Thesis, Open University, 2013. http://oro.open.ac.uk/54932/.
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This study explores women secondary mathematics teachers' experiences of professional learning. Life histories were elicited through semi-structured interviews in the form of guided conversations, supplemented by time-lines of mathematics and of professional learning. Analysis focused on constructed personal experience narratives. Although research demonstrates the features of effective professional learning, teachers' experiences of learning throughout their careers remains under explored. A particular focus in this study is on the ways in which professional learning is supported, providing opportunities for reengagement with mathematics, a subject frequently viewed as inaccessible and masculine. The women's stories are peopled with significant others who provide both models and encouragement, frequently drawn from their own school days and early professional experience. Much professional learning is informal, arising from unstructured reflection on teaching, with teachers accorded neither agency nor consistent support for their learning. The women's narratives provide a perspective on lived experiences of professional learning. Frequently learning is unsupported and spaces to discuss mathematics learning and teaching limited. Teachers appear isolated in restrictive school environments which contribute to a perception of reduced agency. Where opportunities for collaborative professional learning exist, women participate actively in the wider mathematics education community. Analysis of the narratives suggests that teachers' agency over their professional learning needs to increase to create spaces for women to collaborate on mathematics focussed professional learning. The allocation of resources to teacher professional learning should be prioritised. These glimpses reveal the restricted landscape of women mathematics teachers'learning opportunities. Despite these restrictions, however, teachers push at the boundaries. The narratives will support teachers who may draw on the voices of others to help them to make sense of their own development. Further research is warranted to explore the way individuals might develop and utilise their own professional learning narratives.
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Ortz, Courtney. "Aging and Associative and Inductive Reasoning Processes in Discrimination Learning." TopSCHOLAR®, 2006. http://digitalcommons.wku.edu/theses/266.
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The purpose of this study was to investigate how associative and inductive reasoning processes develop over trials in feature positive (FP) and feature negative (FN) discrimination learning. Younger and older adults completed initial and transfer tasks with either consistent or inconsistent transfer. Participants articulated a rule on every trial. The measure of discrimination learning was the number of trials it took participants to articulate the exact rule. In the initial task, older adults articulated the rule more slowly than younger adults in FP discrimination and took marginally more trials to articulate the rule in FN discrimination than younger adults. Age differences were greater in FP discrimination than in FN discrimination learning because younger adults performed well in FP discrimination learning. In the transfer task, older adults articulated the FP rule more slowly than younger adults and both groups articulated the rule more quickly with consistent than inconsistent transfer. Older adults articulated the FN rule slower than older adults. The differences in trials to articulate the FN rule for the two groups were somewhat larger for inconsistent transfer than consistent transfer. Discrimination learning was explained in terms of associative and inductive reasoning processes reasonably well. The measure of associative processes was forgotten responses, whereas the measures of inductive reasoning processes were irrelevant cue shifts and perseverations. In FP discrimination learning in the initial task, older adults had a greater proportion of forgotten responses, irrelevant cue shifts, and marginally more perseverations than younger adults. Therefore, older adults had more difficulty with associative and inductive reasoning processes than younger adults in FP discrimination. In FN discrimination, older adults had a greater proportion of forgotten responses than younger adults. Older and younger adults had a similar number of irrelevant cue shifts and perseverations. Therefore, in FN discrimination older adults had more difficulty with associative processes than younger adults. Both groups had difficulty with inductive reasoning processes. In FP discrimination in the transfer task, older adults had a greater proportion of forgotten responses, irrelevant cue shifts, and perseverations than younger adults, and these proportions were similar in consistent and inconsistent transfer. Therefore, in FP discrimination older adults had more difficulty than younger adults with both associative and inductive reasoning processes. Both processes were similar with regards to consistent and inconsistent transfer. In FN discrimination, older adults had a greater proportion of forgotten responses than younger adults, and the proportion of forgotten responses was greater in inconsistent than in consistent transfer. Both groups made a similar number of irrelevant cue shifts, and there was a marginal difference in consistent and inconsistent transfer for this measure with a greater number in inconsistent transfer. Older adults had a greater proportion of perseverations than younger adults. However, there were no differences in the number of perseverations for consistent and inconsistent transfer. Thus, older adults had difficulty with associative and inductive reasoning processes. Younger adults' inductive reasoning skills improved. The associative and inductive reasoning processes in FN discrimination were not as efficient in inconsistent transfer as in consistent transfer.
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Burton, Thomas. "Discrimination Learning and Adaptation in Complex Environments: A Detailed Interrogation." Thesis, The University of Sydney, 2019. http://hdl.handle.net/2123/20825.
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To obtain rewards and avoid punishments in complex and dynamic environments, animals learn to make predictions about upcoming events and select appropriate courses of action to satisfy their biological needs. A common approach for assessing learning and choice behaviour is the use of the appetitive two-choice discrimination task. Despite the widespread use of this method, exactly how animals learn to adapt their choice behaviour through trial-and-error in order to maximise reward remains unknown. Indeed, many studies focus purely on metrics of choice performance (i.e. correct or incorrect) which do not necessarily provide insight into how response selection changes throughout the task acquisition process. Furthermore, averaged data from multiple subjects is normally used to assess the learning curve, which produces inaccurate estimates of the emergence of performance improvements in individuals. Finally, much of our understanding of learning and decision making has, of necessity, been born out of studying discrete elements of behaviour in reduced environmental settings and so does not necessarily allow behaviour to emerge in a naturalistic fashion. The aim of this thesis was to construct a rich profile of behaviour in mice as they acquired a simple visual discrimination task in a complex testing environment. A fine-grained statistical analysis of each individual performance record was executed to systematically identify distinct phases of task acquisition that were then deeply interrogated for a range of behavioural measures that went far beyond simple metrics of choice performance. This close analysis revealed how different choice strategies emerge, develop and interact under different task contingencies. The findings suggest that choice behaviour is highly structured throughout task acquisition and adaptation to change, even when performance is at chance levels. Importantly, multiple abrupt shifts in performance were observed confirming that the discrimination learning curve of individual animals does not necessarily manifest as a gradually increasing function, as proposed by conventional models. Finally, a subtle but detectable role for dopaminergic signalling in the substantia nigra pars compacta during the earliest stage of task acquisition is characterised.
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Conway, Joseph. "WORKPLACE DISCRIMINATION AND LEARNING DISABILITY: THE NATIONAL EEOC ADA RESEARCH PROJECT." VCU Scholars Compass, 2009. http://scholarscompass.vcu.edu/etd/1950.
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Using the Integrated Mission System of the Equal Employment Opportunity Commission (EEOC), the employment discrimination experience of Americans with Learning Disabilities (SLD) is documented for Title I of the Americans with Disabilities Act. The study examines demographic characteristics of the charging parties and the industry of the responding employer against whom complaints are filed. It establishes the nature of the discriminatory act, specifically, pin-points the issue(s) that predicated the allegation, and shows the final outcome or resolution of these complaints. Key dimensions of workplace discrimination as experienced by individuals with LD are detected using two Tests of Proportion. The first test compared individuals with LD to persons who have similar, non-physical disabilities (mental retardation and autism). The second test compares the experience of the LD group to a group representing all other physical, sensory, and neurological disabilities. The Exhaustive CHAID technique is then used to identify and prioritize the most significant variables that contribute to predicting the outcomes of the allegations filed by persons with LD. The comparative findings of both Tests of Proportion in this study indicate that among other industries, Educational Services is more likely to experience allegations of discrimination charged by individuals with LD. Among disability groups, the LD populace was also more likely to make charges of discrimination relative to Assignment, Testing, Harassment, Training, and Discipline. The predictive findings of this study identify eleven specific Issues that drive allegations of discrimination filed by individuals with LD. Derivative implications are discussed as they affect individuals with LD, designated industries, the EEOC, and other stakeholders. Recommendations for future research are made.
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Geller, David 1952. "Knowledge-of-Correct-Response vs. Copying-of-Correct-Response: a Study of Discrimination Learning." Thesis, University of North Texas, 1996. https://digital.library.unt.edu/ark:/67531/metadc278437/.
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Copying prompts with subsequent unprompted practice produced better learning of simple discriminations than feedback only of a correct response without subsequent practice. The Copy condition promoted faster acquisition of accurate performance for all subjects, and shorter response latencies and durations for 3 of 4 subjects. The data support the findings of Barbetta, Heron, and Heward, 1993 as well as Drevno, Kimball, Possi, Heward, Garner III, and Barbetta, 1994. The author proposes that response repertoires are most valuable if easily reacquired at times after original learning. Thus, reacquisition performance data are emphasized. The data suggest that discriminations acquired by copying prompts may result in useful repertoires if a practice procedure is used which facilitates transfer of stimulus control from a formal prompt to a naturally occurring stimulus.
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Jones, Aaron A. Glenn Sigrid S. "Conditional discrimination and stimulus equivalence effects of suppressing derived symmetrical responses on the emergence of transitivity /." [Denton, Tex.] : University of North Texas, 2007. http://digital.library.unt.edu/permalink/meta-dc-3658.
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Madrigal-Bauguss, Jessica Glenn Sigrid S. "Transfer of "good" and "bad" functions within stimulus equivalence classes." [Denton, Tex.] : University of North Texas, 2008. http://digital.library.unt.edu/permalink/meta-dc-6080.
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Tan, C. W. "Using machine learning for decoy discrimination in protein tertiary structure prediction." Thesis, University College London (University of London), 2006. http://discovery.ucl.ac.uk/1445155/.
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In this thesis, the novelty of using machine learning to identify the low-RMSD structures in decoy discrimination in protein tertiary structure prediction is investigated. More specifically, neural networks are used to learn to recognize low-RMSD structures, using native protein structures as positive training examples, and simulated decoy structures as negative training examples. Simulated decoy structures are derived by reversing the sequences of native structures in the set of positive training examples, and threading the reversed sequences back to the native structures. Various input features, extracted from these native and simulated decoy structures, are used as inputs to the neural networks. These input features are the identities of residue pairs, the separation between the residues along the sequence, the pairwise distance and the relative solvent accessibilities of the residues. Various neural networks are created depending on the amount of input features used. The neural networks are tested against the in-house pairwise potentials of mean force method, as well as against a K-Nearest Neighbours algorithm. The second novel idea of this thesis is to use evolutionary information in the decoy discrimination process. Evolutionary information, in the form of PSI-BLAST profiles, is used as inputs to the neural networks. Results have shown that the best performing neural network is the one that uses in put information comprising of PSI-BLAST profiles of residue pairs, pairwise distance and the relative solvent accessibilities of the residues. This neural network is the best among all methods tested, including the pairwise potentials method, in discriminating the native structures. Therefore this thesis has demonstrated the feasibility of using machine learning, more specifically neural networks, in the problem of decoy discrimination. More significantly, evolutionary information in the form of PSI-BLAST profiles has been success fully used to further improve decoy discrimination, particularly in the discrimination of native structures.
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Brown, Morgan E. "Effects of Age, Task Type, and Information Load on Discrimination Learning." TopSCHOLAR®, 2016. http://digitalcommons.wku.edu/theses/1648.
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The feature positive effect (FPE) is a phenomenon in discrimination learning by which learning occurs more quickly when the presence (Feature positive; FP), rather than absence (Feature negative; FN) of a stimulus indicates a response should be made. Although the FPE has been extensively corroborated, a reversal, or feature negative effect (FNE), has been found when a target stimulus comes from a smaller set of stimuli (Fiedler, Eckert, & Poysiak, 1988). Age differences in FP and FN learning indicate that older adults perform more poorly than young adults on both FP and FN tasks, and are likely related to decline in working memory (WM) throughout adulthood (Mutter, Haggbloom, Plumlee, & Schrimer, 2006). This study used a successive discrimination task to compare young and older adults’ performance across FP and FN conditions under low (three of a set of four stimuli were presented) and high (three of a set of six stimuli were presented) information load (IL). Results from rule articulation, final incorrect and 12 consecutive trials correct did not support the hypotheses, but trend analyses provided partial support. Under low IL, YA demonstrated a FN response bias whereas OA showed no bias. Under high IL, YA and OA demonstrated equivalent performance whether the target stimulus was present or absent in the FP condition. In the FN condition OA performed better when the target stimulus was absent while YA showed no bias. These findings indicate FN task performance varies by age and this variation changes based on IL condition.
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De, Pasquale Roberto. "Visual discrimination learning and LTP-like changes in primary visual cortex." Doctoral thesis, Scuola Normale Superiore, 2009. http://hdl.handle.net/11384/85939.
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Brackney, Ryan. "Interactions of equivalence and other behavioral relations: Simple successive discrimination training." Thesis, University of North Texas, 2009. https://digital.library.unt.edu/ark:/67531/metadc12087/.
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The experimenter asked if documented equivalence class membership would influence the development of shared discriminative stimulus function established through simple successive discrimination training. In Experiment 1, equivalence classes were established with two sets of 9 stimuli. Common stimulus functions were then trained within or across the equivalence classes. Greater acquisition rates of the simple discriminations with stimuli drawn from within the equivalence classes were observed. In Experiment 2, a third stimulus set was added with which no equivalence relations were explicitly trained. The findings of Experiment 1 were replicated, but the Set 3 results were inconsistent across subjects. The outcomes of the two experiments demonstrate that equivalence classes have an effect on other behavioral relations which requires further investigation.
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Da, Silva Stephanie P. "Fixed-interval performance as a function of previous temporal discrimination training." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=1968.
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Thesis (M.A.)--West Virginia University, 2001.Title from document title page. Document formatted into pages; contains vi, 93 p. : ill. Includes abstract. Includes bibliographical references (p. 69-76).
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Corns, David Allan. "The effects of graduated stimulus change on learning efficiency in a visual discrimination task." Virtual Press, 1990. http://liblink.bsu.edu/uhtbin/catkey/720342.
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The investigation examined differences in learning efficiency produced by two different methods of discrimination training among regular placement fifth-grade pupils. It was designed to explore possible between-group differences in rate of learning, length of training, mastery rate, recall of learning, and task persistence following training. The experiment consisted of training, an interference task, and a concluding posttest. Two independent groups were formed by random assignment of subjects. The experimental group began training with graduated stimulus change trials--that is, subjects were presented with a succession of three visual discrimination tasks consisting of six trials per task designed to teach correct responding before incorrect alternatives were gradually introduced. Control subjects did not receive graduated stimulus change trials. Instead, they began each task in the training phase with more complex discriminations at trial seven. Pennies were used for reinforcement of correct choices in each group; incorrect selection resulted in no reinforcer delivery. Both groups were then administered a brief exercise designed to inhibit the recall of acquired discriminations. All subjects concluded with a 54-item posttest consisting of intermingled trials from the three-task training phase. The first 21 items were considered mandatory, but the final 33 were optional (i.e., subjects were instructed to complete as many items as they wished and informed that each correct selection earned a penny). Results indicated that graduated stimulus change (GSC) learners committed significantly fewer errors learning the discriminations and mastered significantly more of the training tasks presented than did trial-and-error learners. There was no significant difference between the two groups in the length of training nor in the degree of persistence during posttest voluntary responding. GSC subjects also committed significantly fewer errors on recall than controls although the degree of absolute forgetting in each group was not significantly different. The findings suggest that regular placement, "easy-to-teach" pupils can profit from GSC programming in several important ways. Without lengthening the training process, stimulus control methodologies can render instruction more efficient than trial-and-error procedures for nonimpaired learners. The need is apparent for further experimental research on the application of errorless discrimination procedures to other areas and levels of education.Department of Educational Psychology
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Wilson, A. C. "Hidden disabilities visable discrimination : a conceptualization of discrimination faced by those with specific learning disorders within the Queensland education system." Thesis, Queensland University of Technology, 2000.
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This thesis presents an investigation from a sociological base in the field of disabilities sociology, in that the thesis proposes the hypothesis "that those people with specific learning disorders are discriminated against". To develop this conceptualization this research has conducted an analysis of current qualitative data from textual and historical sources, supported by field research. To gain an insight into the specific discrimination faced by those with specific learning disorder; this study conducted a textual analysis of current Federal and State disabilities and educational legislation. In addition interviews were conducted with a group of 20 individuals with specific learning disorders. This group of people came from a wide range of age groups, eighteen to fifty six, socio-economic back grounds such as a teenager on unemployment benefit to an University lecturer. The gender mix was even. Also to act as a contrast a group of 6 people with disabilities other than specific learning disorders were also interviewed. The disabilities of this group included those who are mobility impaired, and degenerative illnesses to illustrate the problems faced. Some of the other disabilities are a more established disability than specific learning disorders (for example those who are mobility impaired), in the actuality that they recognized, acknowledged as a disability, diagnosed and treatments developed, whereas this is not the case for specific learning disorders. This second group mainly ranged in age from 20 to 40, and the occupations were students, a librarian, and a mother. The gender ratio was file males to one female.
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Guerrero, Luis Fernando. "Disruption of conditional discrimination and its effects on equivalence /." abstract and full text PDF (free order & download UNR users only), 2005. http://0-wwwlib.umi.com.innopac.library.unr.edu/dissertations/fullcit/3198197.
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Thesis (Ph. D.)--University of Nevada, Reno, 2005."May 2005." Includes bibliographical references (leaves 64-72). Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2005]. 1 microfilm reel ; 35 mm.
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Brooks, Joel David. "Discrimination of alcoholics from non-alcoholics using supervised learning on resting EEG." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/87943.
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Thesis: S.M. in Computer Science and Engineering, Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 51-54).
Alcoholism is a widespread problem that can have serious medical consequences. Alcoholism screening tests are used to identify patients who are at risk for complications from alcohol abuse, but accurate diagnosis of alcohol dependence must be done by structured clinical interview. Scalp Electroencephalography (EEG) is a noisy, non-stationary signal produced by an aggregate of brain activity from neurons close to the scalp. Previous research has identified a relationship between information extracted from resting scalp EEG and alcoholism, but it has not been established if this relationship is strong enough to have meaningful diagnostic utility. In this thesis, we investigate the efficacy of using supervised machine learning on resting scalp EEG data to build models that can match clinical diagnoses of alcohol dependence. We extract features from four minute eyes-closed resting scalp EEG recordings, and use these features to train discriminative models for identifying alcohol dependence. We found that we can achieve an average AUROC of .65 in males, and .63 in females. These results suggest that a diagnostic tool could use scalp EEG data to diagnose alcohol dependence with better than random performance. However, further investigation is required to evaluate the generalizability of our results.
by Joel Brooks.
S.M. in Computer Science and Engineering
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Menning, Hans [Verfasser]. "Plasticity in auditory cortex on the grounds of learning discrimination / Hans Menning." München : GRIN Verlag, 2005. http://d-nb.info/1178429024/34.
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Northway, Ruth. "Oppression in the lives of people with learning difficulties : a participatory study." Thesis, University of Bristol, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266904.
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Aime, Mattia. "Circuit mechanisms for encoding discriminative learning in the dorsal prefrontal cortex of behaving mice." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0805/document.
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Chez les mammifères, le néocortex constitue une structure remarquablement plastique assurant leurs multiples capacités d’adaptation et d’apprentissage. Par exemple, l’apprentissage associatif permet à chaque individu d’apprendre les relations entre un événement particulier (un danger par exemple) et les signaux environnementaux qui y sont associés, afin d’en anticiper les conséquences s’il se reproduit dans le futur. Dans le cas de la peur conditionnée, l'apprentissage associatif améliore les capacités de discrimination des signaux de menace et de sécurité, garantissant ainsi une représentation précise de l'environnement. Ce processus comportemental est en partie dépendant de l'interaction entre deux structures cérébrales: le cortex préfrontal (PFC) et le complexe basolatéral de l'amygdale (BLA). Bien que le PFC puisse encoder à la fois les mémoires de menace et de sécurité qui seraient recrutées préférentiellement après l'apprentissage, on ignore toujours si une telle représentation discriminative existe réellement, et si oui, les mécanismes neuronaux et synaptiques qui en sont à l'origine. Au cours de mon travail de thèse, j'ai démontré que l'activité des neurones excitateurs du PFC est nécessaire à la discrimination entre les signaux de menace et de sécurité grâce à la formation d'ensembles spécifiques de neurones. Au cours de l'apprentissage, les neurones pyramidaux sont potentialisés et recrutés au sein de ses ensembles grâce à l'association au niveau dendritique d'événements synaptiques non-linéaires issus des entrées sensorielles avec des entrées synaptiques provenant de la BLA. En conclusion, nos données fournissent la preuve d'un nouveau mécanisme synaptique qui associe, pendant l'apprentissage, l'expérience perçue avec l’état émotionnel transmis par la BLA permettant ainsi la formation d'ensembles neuronaux dans le cortex préfrontalThe ability of an organism to predict forthcoming events is crucial for survival, and depends on the repeated contingency and contiguity between sensory cues and the events (i.e. danger) they must predict. The resulting learned association provides an accurate representation of the environment by increasing discriminative skills between threat and safety signals, most likely as a result of the interaction between the prefrontal cortex (PFC) and the basolateral amygdala (BLA). Although it suggests that local neuronal networks in the PFC might encode opposing memories that are preferentially selected during recall by recruiting specific cortical or subcortical structures, whether such a discriminative representation is wired within discrete prefrontal circuits during learning and by which synaptic mechanisms remain unclear. Here, the work at issue demonstrates that discrimination learning of both safe and fear-conditioned stimuli depends on full activity of the frontal association cortex, and is associated with the formation of cue-specific neuronal assemblies therein. During learning, prefrontal pyramidal neurons were potentiated through sensory-driven dendritic non-linearities supported by the activation of long-range inputs from the basolateral amygdala (BLA). Taken together, these data provide evidence for a new synaptic level mechanism that coincidently link (or meta-associate) during learning features of perceived experience with BLA mediated emotional state into prefrontal memory assemblies
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Martin, Tiffani L. Vaidya Manish. "Does stimulus complexity affect acquisition of conditional discriminations and the emergence of derived relations?" [Denton, Tex.] : University of North Texas, 2009. http://digital.library.unt.edu/ark:/67531/metadc12160.
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Vaidya, Manish. "Conditional Discriminations and Derived Relations: Pinpointing the Moment of Emergence." Thesis, University of North Texas, 1994. https://digital.library.unt.edu/ark:/67531/metadc277971/.
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Four subjects were exposed to the four trial types that define stimulus equivalence from the beginning of the experiment. Procedures were designed to identify acquisition dynamics and relate these observations to responding indicative of equivalence class formation. The data show that, for all subjects, the acquisition of training conditional discriminations was correlated with systematic changes in the subjects' selection responses. The results also indicate that the traditional percent correct measures obscure some important information about the subjects' behavior. The data are discussed in the context of the following statements. 1) Subjects' performances on derived trials are not indicative of relations among stimuli at some other level of analysis but are instances of "equivalencing". 2) "Equivalencing" itself can be characterized as changes in the conditional and conditionally discriminative functions of stimuli involved in the experiment. The potential benefits of this preparation are discussed.
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Saal, Hannes. "Information theoretic approach to tactile encoding and discrimination." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5737.
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The human sense of touch integrates feedback from a multitude of touch receptors, but how this information is represented in the neural responses such that it can be extracted quickly and reliably is still largely an open question. At the same time, dexterous robots equipped with touch sensors are becoming more common, necessitating better methods for representing sequentially updated information and new control strategies that aid in extracting relevant features for object manipulation from the data. This thesis uses information theoretic methods for two main aims: First, the neural code for tactile processing in humans is analyzed with respect to how much information is transmitted about tactile features. Second, machine learning approaches are used in order to influence both what data is gathered by a robot and how it is represented by maximizing information theoretic quantities. The first part of this thesis contains an information theoretic analysis of data recorded from primary tactile neurons in the human peripheral somatosensory system. We examine the differences in information content of two coding schemes, namely spike timing and spike counts, along with their spatial and temporal characteristics. It is found that estimates of the neurons’ information content based on the precise timing of spikes are considerably larger than for spikes counts. Moreover, the information estimated based on the timing of the very first elicited spike is at least as high as that provided by spike counts, but in many cases considerably higher. This suggests that first spike latencies can serve as a powerful mechanism to transmit information quickly. However, in natural object manipulation tasks, different tactile impressions follow each other quickly, so we asked whether the hysteretic properties of the human fingertip affect neural responses and information transmission. We find that past stimuli affect both the precise timing of spikes and spike counts of peripheral tactile neurons, resulting in increased neural noise and decreased information about ongoing stimuli. Interestingly, the first spike latencies of a subset of afferents convey information primarily about past stimulation, hinting at a mechanism to resolve ambiguity resulting from mechanical skin properties. The second part of this thesis focuses on using machine learning approaches in a robotics context in order to influence both what data is gathered and how it is represented by maximizing information theoretic quantities. During robotic object manipulation, often not all relevant object features are known, but have to be acquired from sensor data. Touch is an inherently active process and the question arises of how to best control the robot’s movements so as to maximize incoming information about the features of interest. To this end, we develop a framework that uses active learning to help with the sequential gathering of data samples by finding highly informative actions. The viability of this approach is demonstrated on a robotic hand-arm setup, where the task involves shaking bottles of different liquids in order to determine the liquid’s viscosity from tactile feedback only. The shaking frequency and the rotation angle of shaking are optimized online. Additionally, we consider the problem of how to better represent complex probability distributions that are sequentially updated, as approaches for minimizing uncertainty depend on an accurate representation of that uncertainty. A mixture of Gaussians representation is proposed and optimized using a deterministic sampling approach. We show how our method improves on similar approaches and demonstrate its usefulness in active learning scenarios. The results presented in this thesis highlight how information theory can provide a principled approach for both investigating how much information is contained in sensory data and suggesting ways for optimization, either by using better representations or actively influencing the environment.
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Moura, Anabela. "Prejudice reduction in teaching and learning Portuguese cultural patrimony." Thesis, University of Surrey, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325868.
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Oettinger, Gerald S. (Gerald Samuel). "Learning in labor markets--models of discrimination and school enrollment and empirical tests." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/12596.
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Kim, Jin Woo. "Discrimination against people with learning disabilities in the labour market in South Korea." Thesis, University of Birmingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.633214.
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This research explores Korean disability employment policy and discrimination against people with learning disabilities in the labour market. Breaking with the traditional academic approach to researching disability in Korea, it adopts a social model of disability and involves people with learning disabilities in the research process. Utilising the conceptual frameworks of 'political economy', 'the social model of disability' and 'legal discrimination', it investigates the employment of people with learning disabilities in open employment and sheltered workshops in Korea. Using group interviews with parents of people with learning disabilities and individual interviews with policy makers, sheltered workshops managers, people with learning disabilities and their parents, it focuses on the discriminative characteristics of current Korean disability employment policy, its impact on the participation of people with learning disabilities in the labour market, and their parents' understanding of how this discriminative reality impacts on the employment opportunities available to their offspring. The research findings are discussed in relation to 'direct and indirect legal discrimination' and 'commonality and difference'. The conclusions reached are that the disability employment policy in Korea is characterised by direct and indirect discrimination against people with learning disabilities, and this discriminative reality is not challenged by parents of people with learning disabilities in Korea who take on the responsibility of providing for their offspring's future lives.
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Frambourg, Cédric. "Apprentissage d'appariements pour la discrimination de séries temporelles." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00948989.
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Il n'est pas rare dans les applications que les profils globaux des séries temporelles soient dissimilaires au sein d'une même classe ou, inversement, exhibent des dynamiques similaires pour des classes différentes. L'objectif de ce travail consiste à discriminer de telles structures de séries temporelles complexes. Nous proposons une nouvelle approche d'apprentissage d'appariements discriminants visant à connecter les séries temporelles selon les caractéristiques partagées dans les classes et différentielles entre les classes. Cette approche est fondée sur un critère de variance/covariance pour la pénalisation des liens entre les observations en fonction de la variabilité intra et inter classes induite. Pour ce faire, l'expression de la variance/covariance classique est étendue à un ensemble de séries temporelles, puis à des classes de séries. Nous montrons ensuite comment les appariements appris peuvent être utilisés pour la définition d'une métrique locale, pondérée, restreignant la comparaison de séries à leurs attributs discriminants. Les expérimentations menées soulignent la capacité des appariements appris à révéler des signatures fines discriminantes et montrent l'efficacité de la métrique apprise pour la classification de séries temporelles complexes.
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Gaskin, Stephane. "Roles of the hippocampus, entorhinal cortex, amygdala and fimbria-fornix in a spatial discrimination on the radial maze." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102978.
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The role of the dorsal hippocampus, entorhinal cortex, amygdala and fimbria fornix in spatial discrimination was investigated using temporary inactivation and lesioning methods. Spatial learning was tested in a conditioned cue preference (CCP) paradigm involving three phases of behavioral testing on an 8-arm radial maze. In the first phase (pre-exposure) rats were given unreinforced pre-exposure trials in which they were free to move on two adjacent arms of the maze on three consecutive days. Rats were then alternately confined to the ends of the arms for eight days (training), one arm that contained food (Paired-arm) and one that did not (Unpaired-arm). The rats were then given a choice between the two arms with no food present. Only when given unreinforced pre-exposure trials did rats spend more time in the Paired-arm than in the Unpaired-arm, a CCP. Rats with muscimol induced inactivation of the dorsal hippocampus during unreinforced pre-exposure acquired a CCP for the Paired-arm but were impaired with hippocampal inactivation during training or testing. Inactivation of the entorhinal cortex resulted in impairment in all phases of the paradigm. Inactivation of the dorsal hippocampus in the Unpaired but not Paired-arm only resulted in impairment. The effects of dorsal hippocampus inactivation in either the Paired or Unpaired arms were reversed in rats with combined amygdala lesions\dorsal hippocampus inactivation. Rats with fimbria fornix\entorhinal cortex disconnections during pre-exposure were also impaired. These results reveal that spatial learning may rely on the interactions between the hippocampus, entorhinal cortex, amygdala, and fimbria fornix and that the dogma that the hippocampus mediates all forms of spatial learning requires revision.
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Levine, Joshua A. Vaidya Manish. "An attempt to dissociate effects of response requirements and sample duration in conditional discrimination learning with pigeons." [Denton, Tex.] : University of North Texas, 2009. http://digital.library.unt.edu/permalink/meta-dc-10988.
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Kuhn, Robin Merritt Rosales-Ruiz Jesus. "Assessing the stimulus control of observers." [Denton, Tex.] : University of North Texas, 2009. http://digital.library.unt.edu/ark:/67531/metadc12146.
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Shaheen, Kemal. "Exploring Dalit participation in learning and the transformative potential of self reflective inquiry." Thesis, Canterbury Christ Church University, 2007. http://create.canterbury.ac.uk/12119/.
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In this thesis I explore barriers to, and opportunities for, the participation in learning (and emancipation) of a profoundly subjugated segment of Indian Society referred to as Dalits. Accounting for approximately 16 per cent of the Indian population (according to the 2001 Census), Dalits have been excluded from education and wider society on the basis of their inferior position in the hierarchical division of society known as the Caste System. A raft of statistics indicate the extent of this exclusion and the disproportionate representation of Dalit children in those who have never been enrolled in school, drop out before completin primary education, or are illiterate. However this thesis is not about numbers and I examine the relevant themes from a different perspective. Drawing on evidence and insights garnered by employing a variety of research techniques (literature review, fieldwork in India, autobiographical episodes and self-reflective inquiry) I examine opportunities for Dalit participation in learning (not just formal schooling) that will stimulate this subjugated people to critically reflect upon the circumstances of their oppression and take action to challenge it. This thesis is, in part, an exploration of the contours of a liberating education. At the heart of this thesis lies an examination of the transformative potential of self-reflective inquiry. I argue that, if conducted sufficiently rigorously, the process of critical self-reflection can lead to a profound transformation in human consciousness and a radical shift in the relationship between Self and Other. I suggest that this insight is pivotal if we are to deepen our understanding of the barriers to, and opportunities for, Dalit emancipation and participation in learning.
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Chen, Xing. "Perceptual learning of contrast discrimination and its neural correlates in macaque V4 and V1." Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2403.
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We make frequent evaluations of subtle contrast differences in our visual environment, and often under challenging illumination conditions, whether photopic, scotopic or mesopic. Our contrast discrimination abilities are rigorously honed from an early age, and we continue to carry out these fine perceptual judgments throughout our lifetimes. Thus, the issue of whether substantial improvement in contrast discrimination is possible during later periods in life, such as during adulthood- and the circumstances that allow this- has sometimes come under discussion. Our adult macaque subjects underwent extensive training on a contrast discrimination task, in which stimuli were positioned at a variety of peripheral and parafoveal locations. We present clear evidence of contrast perceptual learning at the behavioural level and show that these changes have neuronal correlates primarily in V4, rather than in V1. Learning was specific to stimulus location and spatial frequency, but was transferable across orientations; it took place to a limited degree under stimulus roving conditions, and could be either facilitated or impeded by the addition of flanker stimuli, depending on the subject. Upon removal of flankers, levels of psychometric and neurometric performance returned to their pre-flanker state. In V4, learning-induced changes encompassed a shift in the point of neurometric equality and the semi-saturation constant (C50) towards the trained contrast; a decrease in noise correlations across channels; and an increase in choice probability. In V1, enhancements in performance were characterised by an increase in spike discriminability; a shift in the point of neurometric equality and the C50 towards the trained contrast(s); and a widening in the range and a steepening of the contrast response function, during the early phase of training. Deteriorations in performance were accompanied by the reverse effects on V1 activity; furthermore, a general decrease in V1 firing rates occurred when training was carried out over an extended period of time, after performance had reached its peak.
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Rayburn-Reeves, Rebecca Marie. "AN ANALYSIS OF BEHAVIORAL FLEXIBILITY AND CUE PREFERENCE IN PIGEONS UNDER VARIABLE REVERSAL LEARNING CONDITIONS." UKnowledge, 2011. http://uknowledge.uky.edu/psychology_etds/1.
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Behavioral flexibility, the ability to change behavior in accordance with the changing environment, was studied in pigeons using a series of reversal learning paradigms. All experiments involved a series of 5-trial sequences and I was interested in whether pigeons are sensitive to the reversal by switching to the other alternative after a single error. In Experiments 1 and 2, the overall probability of the two stimuli was equated over sequences, but the probability correct of the two stimuli changed across trials. In both experiments, subjects showed no sensitivity to the differences in sequence type. Instead they used the overall average of the probability of reinforcement on each trial as the basis of choice.
In the final two experiments, the likelihood that a reversal would occur on a given trial was equated such that there was an equal overall probability that the two stimuli would be correct on a given trial, but the overall probability of each stimulus being correct across sequences favored the second correct stimulus (S2). In Experiment 3, the overall probability of S2 correct was 80%, and results showed that subjects consistently chose S2 regardless of sequence type or trial number. In Experiment 4, the overall likelihood of S2 correct was 65%, and results showed that subjects began all sequences at chance, and as the sequence progressed, began choosing S2 more often.
In all experiments, subjects showed remarkably similar behavior regardless of where (or whether) the reversal occurred in a given sequence. Therefore, subjects appeared to be insensitive to the consequences of responses within a sequence (local information) and instead, seemed to be averaging over the sequences based on the overall probability of reinforcement for S1 or S2 being correct on each trial (aggregate information), thus not maximizing overall reinforcement. Together, the results of this series of experiments suggest that pigeons have a basic disposition for using the overall probability instead of using local feedback cues provided by the outcome of individual trials. The fact that pigeons do not use the more optimal information afforded by recent reinforcement contingencies to maximize reinforcement has implications for their use of flexible response strategies under reversal learning conditions.
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Michniewicz, Leslie (Leslie A. ). "The Role of a Point Loss Contingency on the Emergence of Derived Relations in the Absence of Original Relations." Thesis, University of North Texas, 1997. https://digital.library.unt.edu/ark:/67531/metadc279016/.
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The role of point loss for symmetrical relations introduced simultaneously with probe trials in the absence of original relations on all probe trial performances was evaluated. Training was completed after six conditional discriminations were established in two contexts. Point loss was introduced simultaneously with probe trials in the absence of original relations in the first context. Probe trials with no point loss in the absence of original relations were introduced in the second context. The simultaneous introduction of probe trials and the point loss contingency may in some cases prevent the emergence of an equivalence class in the context that contained the point loss as well as in the context where no point loss occurred.
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Karellou, Joanna. "Perspectives on the sexuality of young people with learning disabilities in Greece." Thesis, Keele University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327634.
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Gong, Mingliang. "Orientation discrimination in periphery: Surround suppression or crowding?" Miami University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=miami1430433449.
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Jones, Aaron A. "Conditional Discrimination and Stimulus Equivalence: Effects of Suppressing Derived Symmetrical Responses on the Emergence of Transitivity." Thesis, University of North Texas, 2007. https://digital.library.unt.edu/ark:/67531/metadc3658/.
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Symmetry suppression was conducted for five subjects who demonstrated a tendency to derive equivalence relations based on conditional discrimination training in a match-to-sample procedure. Symmetry suppression was applied in three consecutive sessions in which symmetrical responses were suppressed for one stimulus class in the first condition, two stimulus classes in the second condition, and all three stimulus classes in the final condition. Symmetry suppression slowed the emergence of transitivity for two subjects and prevented it for the other three. Results indicated that unplanned features of stimulus configurations emerged as discriminative variables that controlled selection responses and altered the function of consequent stimuli. Disruption of cognitive development by conflicting contingencies in natural learning environments is discussed.
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Levine, Joshua. "An Attempt to Dissociate Effects of Response Requirements and Sample Duration in Conditional Discrimination Learning with Pigeons." Thesis, University of North Texas, 2009. https://digital.library.unt.edu/ark:/67531/metadc10988/.
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Attempts to control various aspects of response requirements and sample viewing durations of sample stimuli show that an increase in both facilitates acquisition of conditional discriminations. Despite these attempts, few empirical data exist that demonstrate the relative contributions of both response- and time-dependent schedules. In addition, viewing opportunities of sample stimuli are present outside of the researchers' control, allowing for 'unauthorized sample viewing.' This study employed a titrating delay matching-to-sample procedure to systematically control various aspects of response requirements and sample viewing durations to independently assess their relative contributions towards conditional discrimination performance. Four pigeons worked on a titrating delay matching-to-sample procedure in which the delay between sample offset and comparison onset continuously adjusted as a function of the accuracy of the pigeons' choices. Results show sample viewing durations contribute most toward conditional discrimination performance. The data show 'unauthorized sample viewing' improved acquisition of conditional discriminations and should be a consideration in design of future research.
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Fernando, Kayla Dana. "Sex Differences in Serotonin (5-HT) Activity During Safety Learning." Thesis, Boston College, 2018. http://hdl.handle.net/2345/bc-ir:108020.
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Thesis advisor: John P. ChristiansonPatients with posttraumatic stress disorder (PTSD) often show impaired ability to discriminate between “danger” and “safety” cues. Women are more than twice as likely to be diagnosed with PTSD as compared to men; however, translational research has largely relied on the use of male subjects despite evidence of sex differences in fear-motivated behaviors. Serotonergic activity, originating in the dorsal raphe nucleus (DRN) of the central nervous system (CNS), has been found to modulate fear discrimination in males and may contribute to sex differences observed in a Pavlovian fear discrimination paradigm. In this study, male and intact female Sprague-Dawley rats were exposed to fear conditioning with (CS+/CS-) or without (CS+) a safe conditioned stimulus, then subsequently sacrificed for immunohistochemical analysis of serotonergic activity via quantification of tryptophan hydroxylase (TPH) and Fos in the DRN. Females exhibited more rapid and robust discrimination between the CS+ danger cue and CS- safety cue as compared to males. Regardless of condition, females had more double-labeled TPH+Fos cells compared to males, but males had larger variation in TPH+Fos expression compared to females. A parabolic function for TPH+Fos counts predicted fear discrimination in males, but not females, reinforcing the view that serotonin is a modulator of safety-related behavior in males
Thesis (BS) — Boston College, 2018
Submitted to: Boston College. College of Arts and Sciences
Discipline: Arts and Sciences Honors Program
Discipline: Biology
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Greenberg, Paul Arthur. "Functional Stability and Learning in the Dorsolateral Prefrontal Cortex." Diss., Tucson, Arizona : University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1030%5F1%5Fm.pdf&type=application/pdf.
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