Retrospective revaluation as simple associative learning

Backward blocking, unovershadowing and backward conditioned inhibition are examples of "retrospective revaluation" phenomena, that have been suggested to involve more than simple associative learning. Models of these phenomena have thus employed additional concepts, e.g. appealing to attentional effects or more elaborate learning mechanisms. I show that a suitable representation of stimuli, paired with a careful analysis of the discriminations faced by animals, leads to an account of these and other phenomena in terms of a simple "elemental" model of associative learning, with essentially the same learning mechanism as the Rescorla and Wagner (1972) model. I conclude with a discussion of some implications for theories of learning

Chronic fatigue syndrome; an approach combining self-management with graded exercise to avoid exacerbations.

Controversy regarding the aetiology and treatment of patients with chronic fatigue syndrome (CFS) continues to affect the medical professions. The Cochrane collaboration advises practitioners to implement graded exercise therapy for CFS sufferers using cognitive behavioural principles. In contrast there is evidence that exercise can induce symptom exacerbations in CFS where too vigorous exercise/activity promotes immune dysfunction, which in turn increases symptoms in patients with CFS. When designing and implementing an exercise programme it is important to be aware of both these seemingly opposing view points in order to deliver a programme without any detrimental effects on CFS pathophysiology. Using evidence from both the biological and clinical sciences, the present manuscript explains that graded exercise therapy for people with CFS can be safely undertaken without detrimental effects to the immune system. Exercise programs should be designed to cater for individual physical capabilities and should also account for the fluctuating nature of symptoms commonly reported by people with CFS. In line with cognitive behaviourally and graded exercise-based strategies, self-management for people with CFS involves encouraging the patients to pace their activities and respect their physical and mental limitations with the ultimate aim of improving their everyday function