Maintenance-feeding effort affects instrumental performance

The effort required of rats to obtain food, employing standard maintenance-feeding procedures, can affect the effort subsequently expended in an instrumental-learning task. Rats received 43 food-rewarded runway trials followed by access to food (a) on the home-cage floor, or (b) from a hopper attached to the home-cage's wiremesh front wall. Hopper feeding involved the greater effort since the rats had to gnaw the food pellets through the wire mesh. Following 9 or 27 days of maintenance feeding, the rats were returned to the runway for one rewarded trial and 16 extinction trials. The hopper-fed rats ran faster than floor-fed rats on the rewarded test trial. In extinction, long-term maintenance feeding produced faster subsequent running times by the hopper-fed rats than the floor-fed rats. Short-term maintenance feeding, on the other hand, produced slower running times by the hopper-fed rats than the floor-fed rats. The results are consistent with previous findings of transfer of effort across behaviours and suggest that the effort required for reinforcement in the maintenance environment can systematically influence the effectiveness of various experimental treatments.     

A computational model of visual stability and change detection during eye movements in real-world scenes

Visual cognition and change detection critically depend on attention and gaze. A central question is the exact involvement of attention in change detection. This paper proposes a detailed computational model to illuminate the nature of visual stability and change detection during eye movements. Consistent with experimental findings the model predicts that change detection at the saccade endpoint is relatively easy. According to our model the planning of an eye movement provides an enhanced sensory processing of an object at the saccade target. This facilitates the memorization of that object. A comparison of the memorized target template with the representation after saccade allows for change detection. We hypothesize that the spatial reentry signal that emerges from planning an eye movement could be a crucial neural basis of visual stability.     

Personal responsibility,empowerment and medical utilization: a theoretical framework for considering counselling and offset costs

The problem of effectively managing patients with functional somatic symptoms remains huge in both primary and hospital care, although the potential benefits of mental health interventions such as counselling or psychotherapy are still not widely accepted. Unfortunately, the cost-effective evaluation of counselling has been beset by methodological problems, which stem from attempting to make comparisons between counsellors with different types of training, therapeutic approach and case mix. Since these real-world variations in counselling practice are likely to remain, it is proposed that a different approach to the evaluation of cost-effectiveness should be adopted in the hope of accelerating acceptance of the value of psychological interventions for the army of patients who are currently labelled as ‘difficult’ or ‘heartsink’ and who do not receive the treatment they deserve from the health-care services. It is proposed that, since the common aim of almost all mental health interventions is to engender or enhance a sense of ‘personal responsibility’ in patients/clients, this core objective should form an agreed ‘yardstick’ against which to evaluate the impact of various mental health interventions. Furthermore, since personal responsibility and future health-care utilization (and associated costs) can be assumed to be directly causally related, it is proposed that offset costs should form the basis for future cost-effectiveness evaluations.     

A Note on Hahn's Philosophy of Logic

Hans Hahn, mathematician, philosopher and co-founder of the Vienna Circle, attempted to reconcile the validity and applicability of both logic and mathematics with a strict empiricism. This article begins with a review of this attempt, focusing on his view of the relation of language to logic and his answer to the question of why we need logic. I then turn to some recent work by Stephen Yablo in an attempt to show that Yablo's fictionalism, and in particular his use of metaphor, can shed light on Hahn's philosophy of logic.