Précis of memory: a philosophical study

This is a response to three critical discussions of my book Memory: A Philosophical Study (Oxford University Press 2010): Marya Schechtman, “Memory and Identity”, Fred Adams, “Husker Du?”, and Sanford Goldberg “The Metasemantics of Memory”.     

The effect of positive events at work on after-work fatigue: they matter most in face of adversity

There is evidence that daily negative events at work enhance fatigue. In contrast, positive events may trigger processes that increase, but also processes that decrease, energetic resources. Accordingly, results regarding a main effect of positive events on fatigue have been mixed. However, a clearer pattern between positive events and fatigue can be expected under adverse circumstances (i.e., accumulation of negative events, high chronic stressors). Positive events may facilitate coping and accelerate recovery processes and, thus, reduce resource drain due to daily negative events and chronic stressors. Predicting fatigue in a diary study with 76 employees, we investigated interactions between daily positive events and (a) daily negative events and (b) chronic social stressors. Multilevel modeling revealed that negative but not positive events were associated with increased end-of-work fatigue. However, positive events interacted with negative events and with chronic social stressors. As expected, positive events were negatively associated with fatigue only on days with many negative events, but not so on days with few negative events. Analogously, positive events were negatively associated with fatigue only among employees with high, compared with low, chronic social stressors. We conclude that the beneficial short-term effects of positive events on energetic resources are largely confined to adverse circumstances.     

AGM 25 Years

The 1985 paper by Carlos Alchourrón (1931–1996), Peter Gärdenfors, and David Makinson (AGM), “On the Logic of Theory Change: Partial Meet Contraction and Revision Functions” was the starting-point of a large and rapidly growing literature that employs formal models in the investigation of changes in belief states and databases. In this review, the first twenty-five years of this development are summarized. The topics covered include equivalent characterizations of AGM operations, extended representations of the belief states, change operators not included in the original framework, iterated change, applications of the model, its connections with other formal frameworks, computatibility of AGM operations, and criticism of the model.     

Differential effects of stimulus characteristics during knee joint perturbation on hamstring and quadriceps reflex responses

When stretching muscles of the ankle joint, stretch velocity and amplitude were shown to selectively influence specific parts of the stretch reflex. The present study investigated whether similar effects can be observed at the knee joint. Seventeen subjects were exposed to sudden anterior tibial translations. The influence of stimulus amplitude was analyzed by applying a low (LIMP) or high impulse (HIMP). To investigate the influence of velocity, rate of force development of the perturbation was chosen either low (LRFD) or high (HRFD). Activation of biceps femoris (BF), semitendinosus (ST), vastus medialis (VM) and vastus lateralis (VL) was calculated in four consecutive timeframes (P0, P1, P2, P3). During P1, RFD (ST: p < .05; BF: p < .01; VM: p < .05; VL: p > .05) and during P2, impulse (ST: p < .05; BF: p < .01; VM: p < .01; VL: p < .01) did significantly influence reflex activation. The present study showed that stimulus characteristics influenced specific reflex components of knee joint muscles. As only hamstring muscles were stretched, whereas quadriceps was unloaded, it is concluded that different mechanisms like homonymous and heteronymous muscle afferents as well as joint and skin afferents might contribute to the reflex responses.     

Instructional development for teachers in higher education: Effects on students’ perceptions of the teaching–learning environment

Background. Although instructional development for teachers has become an important topic in higher education, little is known about its actual impact. In particular, evidence regarding the impact of teachers’ instructional development on students’ perceptions of the teaching–learning environment is scarce. Aims. The impact of an instructional development programme for beginning university teachers on students’ perceptions of the teaching and learning environment was investigated. We also explored whether this impact is dependent on class size and student level (first years vs. non‐first years). Sample. Quantitative data were gathered from more than 1,000 students at pre‐ and post‐tests, using a quasi‐experimental design. Method. A multi‐level analysis was conducted in which five models were estimated. Results. A basic model made clear that teachers did differ from each other with respect to the dependent variables concerned; however, differences in scale scores also resulted to a large extent from differences between students. A second model, in which the moderating impact by way of teacher characteristics, context, and student characteristics was not taken into account, reported no significant effect of training. A third model, examining the net impact of instructional development revealed some impact, which was, remarkably, negative. A first interaction model proved a differential impact of instructional development for teachers teaching first years and those teaching non‐first years. A second one showed that the impact of training depended on the number of students one teaches. Conclusions. Instructional development for teachers in higher education does not easily result in effects on students’ perceptions of the teaching and learning environment. Perspectives for further research into instructional development are discussed.     

Finite Contractions on Infinite Belief Sets

Contractions on belief sets that have no finite representation cannot be finite in the sense that only a finite number of sentences is removed. However, such contractions can be delimited so that the actual change takes place in a logically isolated, finite-based part of the belief set. A construction that answers to this principle is introduced, and is axiomatically characterized. It turns out to coincide with specified meet contraction.     

In Defence of Ockhamism

Ockhamism implies that future contingents may be true, their historical contingency notwithstanding. It is thus opposed to both the Peircean view according to which all future contingents are false, and Supervaluationist Indeterminism according to which all future contingents are neither true nor false. The paper seeks to defend Ockhamism against two charges: the charge that it cannot meet the requirement that truths be grounded in reality, and the charge that it proves incompatible with objective indeterminism about the future. In each case, the defence draws on the idea that certain truths are truths only courtesy of others and of what makes the latter true. After introduction of the Ockhamist view, its competitors and implications, a suitable definition of grounded truth is being devised that both is faithful to the spirit of the grounding-requirement and allows the Ockhamist to heed that requirement quite comfortably. Then two senses in which the future might be open are being introduced, indeterminacy as failure of predetermination by past and present facts, and indeterminacy as failure of entailment by past and present truths. It is argued that while openness in the former sense, but not in the latter sense, coheres with the Ockhamist view, it is only openness in the former sense that matters for objective indeterminism.     

Psychoanalytische Psychotherapie mit niedriger Sitzungsfrequenz

Compared to Freud??s use of six sessions a week, the frequency of therapy has now decreased to a maximum of three or four sessions. The current field of applied psychoanalysis using only one or two sessions a week is of much higher relevance for the worldwide supply of the population with psychotherapy. Not only frequency and duration have decreased over the years but also the sum of applied sessions per patient. This is especially the case in psychodynamic short term psychotherapy. With the change in frequency a change in therapy technique took place resulting in a more active and attentive therapist, an interactive pattern with more dialogue and an avoidance of regressive movements of the patient. The crucial role concerning the work with transference and resistance was maintained in tendency but the specific techniques also underwent modifications. The empirical state of psychodynamic psychotherapy is better than it used to be but further studies are urgently needed.     

Anxiety, a benefit and detriment to cognition: behavioral and magnetoencephalographic evidence from a mixed-saccade task

Anxiety is typically considered an impediment to cognition. We propose anxiety-related impairments in cognitive-behavioral performance are the consequences of enhanced stimulus-driven attention. Accordingly, reflexive, habitual behaviors that rely on stimulus-driven mechanisms should be facilitated in an anxious state, while novel, flexible behaviors that compete with the former should be impaired. To test these predictions, healthy adults (N=17) performed a mixed-saccade task, which pits habitual actions (pro-saccades) against atypical ones (anti-saccades), under anxiety-inducing threat of shock and safe conditions. Whole-head magnetoencephalography (MEG) captured oscillatory responses in the preparatory interval preceding target onset and saccade execution. Results showed threat-induced anxiety differentially impacted response times based on the type of saccade initiated, slowing anti-saccades but facilitating erroneous pro-saccades on anti-saccade trials. MEG source analyses revealed that successful suppression of reflexive pro-saccades and correct initiation of anti-saccades during threat was marked by increased theta power in right ventrolateral prefrontal cortical and midbrain regions (superior colliculi) implicated in stimulus-driven attention. Theta activity may delay stimulus-driven processes to enable generation of an anti-saccade. Moreover, compared to safety, threat reduced beta desynchronization in inferior parietal cortices during anti-saccade preparation but increased it during pro-saccade preparation. Differential effects in inferior parietal cortices indicate a greater readiness to execute anti-saccades during safety and to execute pro-saccades during threat. These findings suggest that, in an anxiety state, reduced cognitive-behavioral flexibility may stem from enhanced stimulus-driven attention, which may serve the adaptive function of optimizing threat detection.