Is performance in task-cuing experiments mediated by task set selection or associative compound retrieval?

Journal ArticleThis article may not exactly replicate the final version published in the APA journal. It is not the copy of record. The definitive version was published as: Forrest, C.L.D., Monsell, S., and McLaren I.P.L. (2014). Is performance in task-cuing experiments mediated by task-set selection or associative compound retrieval? Journal of Experimental Psychology: Learning, Memory and Cognition, 40, 1002-1024. http://dx.doi.org/10.1037/a0035981© 2014 American Psychological AssociationTask-cuing experiments are usually intended to explore control of task set. But when small stimulus sets are used, they plausibly afford learning of the response associated with a combination of cue and stimulus, without reference to tasks. In 3 experiments we presented the typical trials of a task-cuing experiment: a cue (colored shape) followed, after a short or long interval, by a digit to which 1 of 2 responses was required. In a tasks condition, participants were (as usual) directed to interpret the cue as an instruction to perform either an odd/even or a high/low classification task. In a cue + stimulus → response (CSR) condition, to induce learning of mappings between cue-stimulus compound and response, participants were, in Experiment 1, given standard task instructions and additionally encouraged to learn the CSR mappings; in Experiment 2, informed of all the CSR mappings and asked to learn them, without standard task instructions; in Experiment 3, required to learn the mappings by trial and error. The effects of a task switch, response congruence, preparation, and transfer to a new set of stimuli differed substantially between the conditions in ways indicative of classification according to task rules in the tasks condition, and retrieval of responses specific to stimulus-cue combinations in the CSR conditions. Qualitative features of the latter could be captured by an associative learning network. Hence associatively based compound retrieval can serve as the basis for performance with a small stimulus set. But when organization by tasks is apparent, control via task set selection is the natural and efficient strategy

Elemental representation and configural mappings: combining elemental and configural theories of associative learning.

Journal ArticleResearch Support, Non-U.S. Gov'tCopyright © Psychonomic Society, Inc. 2012In this article, we present our first attempt at combining an elemental theory designed to model representation development in an associative system (based on McLaren, Kaye, & Mackintosh, 1989) with a configural theory that models associative learning and memory (McLaren, 1993). After considering the possible advantages of such a combination (and some possible pitfalls), we offer a hybrid model that allows both components to produce the phenomena that they are capable of without introducing unwanted interactions. We then successfully apply the model to a range of phenomena, including latent inhibition, perceptual learning, the Espinet effect, and first- and second-order retrospective revaluation. In some cases, we present new data for comparison with our model's predictions. In all cases, the model replicates the pattern observed in our experimental results. We conclude that this line of development is a promising one for arriving at general theories of associative learning and memory.ESRCExeter Graduate FellowshipExeter Associate Research Fellowshi

Competitive utilization of glucose and glycerol by Escherichia coli

1) When glycerol is the sole source of carbon and energy in E.coli its utilization is regulated by the level of glycerokinase and the intracellular concentration of fructose-1,6-diphosphate, the negative modifier of glycerokinase activity. 2) E.coli 15224 exhibits diauxic growth on a mixture of glucose and glycerol in. simple defined media under aerobic conditions. 3) When cells have been trained to and are growing on glycerol, the addition of glucose represses, almost immediately, the synthesis of glycerokinase. Glycerol utilization falls by about 50% at the time of glucose challenge and continues to decrease for about 50 min, when it ceases altogether, and does not start again until glucose is exhausted. After glucose challenge, the glycerol carbon used continues to enter protein, nucleic acid and lipid with a slight increase in the proportion entering the last. The delay before glycerol utilization is completely shut off suggests that this process depends on some feature of the glucose phenotype which is not present in glycerol trained cells. This is supported by the observation that the addition of glucose to chloramphenicol treated cells depresses the rate of glycerol metabolism but never abolishes it. 4) In the above case total inhibition of glycerol utilization is an example of 'catabolite inhibition' (McGinnis & Paigen, 1969). In this case glycerol metabolism could be regulated by fructose-1,6-diphosphate concentration which, in turn, could reflect the rate of glucose metabolism. However fruetose-1,6-diphosphate inhibits glycerokinase of this strain to a maximum of 85%. Direct measurement shows that the intracellular concentration of fructose-1,6-diphosphate does not change significantly on glucose challenge. The fructose-1,6-diphosphate in cells growing on glycerol permits 31% of the glycerokinase activity to be utilized and, after glucose challenge, at least 26% of glycerokinase activity would be used if fructose-1,6-diphosphate was the only regulator. Thus total inhibition of glycerol metabolism cannot depend on glycerokinase inhibition by fructose-1,6-diphosphate. Glycerokinase is not inhibited by any other metabolite of glucose which has been tested. 5) The rate of free diffusion of glycerol into cells of E.coli is sufficient to account for a substantial proportion of the rate of glycerol utilization in the absence of glucose. Furthermore glucose does not affect the facilitated diffusion of glycerol. Thus glucose does not inhibit glycerol utilization by regulation of the rate of entry of glycerol into the cells. 6) The rate of glycerol utilization, the rate of glucose utilization and the ratios of glycerokinase and glucose PTS are all interrelated. The utilization of glucose and glycerol are mutually inhibitory, the degree of inhibition depending on the relative levels of glycerokinase and glucose PTS. However the rate of glycerol utilization depends on the rate of glucose utilization when the enzyme levels are constant. A model has been proposed in which glycerokinase and glucose PTS compete for a common element. This has been supported by observations, both in growing cells and washed cell suspensions, and it is speculated that the common element may involve the energy requirement of the first steps of glycerol and glucose utilization

Task switching without knowledge of the tasks.

CogSci 2012 - 34th annual meeting of the Cognitive Science Society, Sapporo, Japan, 1-4 August 2012Task-cuing paradigms are typically taken to explore control of task-set. However, they can be construed as requiring not selection of a task-set, just retrieval of a cue+stimulus-->response (CSR) mapping. In this paper we considered performance in a task-cuing paradigm in which participants saw a color cue that indicated whether they should classify a digit as odd/even or high/low using one of two responses. Half the participants were instructed in terms of tasks (Task group) whilst the others were required to learn the CSR mappings without mention of tasks (CSR group). Predicted performance under CSR conditions was modeled using an APECS connectionist network. Both the model and CSR group produced small switch costs, mostly due to incongruent stimuli, and large congruency effects that reduced with practice. In contrast, the Task group produced a larger switch-cost and a smaller, stable congruency effect

Comparative Evidence for Associative Learning in Task Switching.

Copyright © 2013 Cognitive Science SocietyHumans can perform several different tasks on the same set of stimuli in rapid alternation. Each task, signaled by a distinct task cue, may require the classification of stimuli using a different stimulus attribute. However, such "task switching" performance comes at a cost, as expressed by weaker performance when switching rather than repeating tasks. This cost is often claimed to be the consequence of a mental reorientation away from the previous task and towards the new task, requiring executive control of behavior. Alternatively, task switching could simply be based on the retrieval of different cue-stimulus-response associations. In this experiment, pigeons learned go-left/go-right discriminations between grating patterns according to either their spatial frequency or their orientation, depending on the color of the pattern (the task cue). When humans solved the same tasks on the basis of verbalizable rules, they responded more slowly and made more errors on trials where they had to switch between tasks than when repeating the same task. Pigeons did not show this "switch cost"; but like humans, their performance was significantly worse when the response (left or right) to a given stimulus varied between tasks than when it stayed the same (the “congruency effect”). Larger effects of both switch costs and congruency were observed in humans learning the tasks by trial and error. We discuss the potential driving factors behind these very different patterns of performance for both humans and pigeons

Medical student wellbeing - a consensus statement from Australia and New Zealand

Abstract Background Medical student wellbeing – a consensus statement from Australia and New Zealand outlines recommendations for optimising medical student wellbeing within medical schools in our region. Worldwide, medical schools have responsibilities to respond to concerns about student psychological, social and physical wellbeing, but guidance for medical schools is limited. To address this gap, this statement clarifies key concepts and issues related to wellbeing and provides recommendations for educational program design to promote both learning and student wellbeing. The recommendations focus on student selection; learning, teaching and assessment; learning environment; and staff development. Examples of educational initiatives from the evidence-base are provided, emphasising proactive and preventive approaches to student wellbeing. Main recommendations The consensus statement provides specific recommendations for medical schools to consider at all stages of program design and implementation. These are:Design curricula that promote peer support and progressive levels of challenge to students.Employ strategies to promote positive outcomes from stress and to help others in need.Design assessment tasks to foster wellbeing as well as learning.Provide mental health promotion and suicide prevention initiatives.Provide physical health promotion initiatives.Ensure safe and health-promoting cultures for learning in on-campus and clinical settings.Train staff on student wellbeing and how to manage wellbeing concerns. Conclusion A broad integrated approach to improving student wellbeing within medical school programs is recommended. Medical schools should work cooperatively with student and trainee groups, and partner with clinical services and other training bodies to foster safe practices and cultures. Initiatives should aim to assist students to develop adaptive responses to stressful situations so that graduates are prepared for the realities of the workplace. Multi-institutional, longitudinal collaborative research in Australia and New Zealand is needed to close critical gaps in the evidence needed by medical schools in our region

Patient initiated aggression and violence in the Australian general practice setting

This is the first national study to be conducted in Australia examining the incidence and prevalence of violence against general practitioners and general practice staff.The research reported in this paper is a project of the Australian Primary Health Care Research Institute, which is supported by a grant from the Australian Government Department of Health and Ageing under the Primary Health Care Research, Evaluation and Development Strategy

On Molinism and Manipulation: Does Molinism answer the problems about Providence, Foreknowledge and Free Will?

Molinism attempts to resolve the incompatibility of divine foreknowledge and human libertarian freedom by the inclusion of the divine will into the solution. Moreover, middle knowledge is providentially useful under the Molinist model because of the way God uses it. This speaks of an integral link between the divine will and intellect that works in such a way as to provide a foreknowledge solution and, allegedly, the best view of providence. Nevertheless, there have been several anti-Molinist arguments by analogy which suggest that the God presented in the Molinist model is a manipulator, and therefore something is lost or undermined in the libertarian freedom that Molinism purports to uphold through its model of foreknowledge and providence. This thesis examines the anti-Molinist charge of manipulation primarily by analysing how God uses information known through middle knowledge. The findings of the anti-Molinist arguments from analogy are reconstructed to form deductive arguments. These are evaluated against standard definitions of objectionable manipulation. It is concluded through analysis of these stronger, deductive arguments that divine providence under the Molinist model is a case of objectionable manipulation, one which many theists, classical or progressive, should find abhorrent. The effects of manipulation on ostensible libertarian freedom are then analysed, leading to the conclusion that Molinist-style manipulation results in a form of free-will compatibilism, ergo, the divine foreknowledge problem is not answered, nor is the result compatible with libertarian freedom. Given that it is close to a form of divine determinism, Molinism is then compared with Calvinism along several lines of criticism, namely whether such a God is good, loving and personal

Social and spatial mobility and self-reported heath in older-age: linkage of the Scottish Longitudinal Study to the Scottish Mental Survey 1947

Background There is debate within the literature as to whether social mobility inflates or constrains health inequalities. The role of geographical mobility is unknown. Objectives We were interested in exploring how spatial and social mobility might impact on health in older age using linked administrative and cohort data. Methods The Scottish Mental Survey 1947 (a 1936 birth cohort of 70,805 individuals with age 11 cognitive ability test scores) was linked to the Scottish Longitudinal Study (a semi-random sample of 5.3% of the Scottish population), and the 1939 register to obtain measures of occupation and geographical location in 1939 and 1991. We examined the movement between three geographical areas (Edinburgh, Glasgow, Other) in Scotland. Four social mobility trajectories were derived. We modelled the relationship between social and geographic mobility and likelihood of having self-reported limiting long term illness (LLTI) at age 65. Findings Those who were geographically mobile to Edinburgh had the lowest rates of self-reported LLTI and those who remained resident in the Glasgow area had the highest rates. The lowest and highest rates of LLTI were found in the socially-static at the top and bottom of the social scale respectively, with intermediate rates seen in the upwardly and downwardly mobile. However neither social nor spatial mobility were significantly associated with health in later life in the fully adjusted model when highest educational qualifications and cognitive ability were included. Being female, having higher education qualifications and being in a higher social class in childhood and adulthood reduced the likelihood of poor health at age 65. Conclusions Although both social class and geographical location were associated with the likelihood of LLTI in later life, social and spatial mobility were not, when factors such as education and cognitive ability were controlled for