An observation on Carnapʼs Continuum and stochastic independencies

We characterize those identities and independencies which hold for all probability functions on a unary language satisfying the Principle of Atom Exchangeability. We then show that if this is strengthen to the requirement that Johnson?s Sufficientness Principle holds, thus giving Carnap?s Continuum of inductive methods for languages with at least two predicates, then new and somewhat inexplicable identities and independencies emerge, the latter even in the case of Carnap?s Continuum for the language with just a single predicate.     

Effects of interlimb practice on coding and learning of movement sequences

An interlimb practice paradigm was designed to determine the role that visual–spatial (Cartesian) and motor (joint angles, activation patterns) coordinates play in the coding and learning of complex movement sequences. Participants practised a 16-element movement sequence by moving a lever to sequentially presented targets with one limb on Day 1 and the contralateral limb on Day 2. Practice involved the same sequence with either the same visual–spatial or motor coordinates on the two days. A unilateral practice condition (control) was also tested where both coordinate systems were changed but the same limb was used. Retention tests were conducted on Day 3. Regardless of the order in which the limbs were used during practice, results indicated that keeping the visual–spatial coordinates the same during acquisition resulted in superior retention. This provides strong evidence that the visual–spatial code plays a dominant role in complex movement sequences, and this code is represented in an effector-independent manner.     

A Thurstonian Analysis of Preference Change

This paper presents a Thurstonian model for the analysis of preference change. Preferences are expressed in the form of rankings, possibly with ties. A vector-autoregression framework is used to investigate relationships between past and current rankings. It is shown that this approach yields a parsimonious and easily interpretable representation of individual preference differences in time-dependent ranking data. A detailed analysis of the 1992 National Election Study illustrates the proposed approach.     

Successive independence and behavioral contrast in a closed economy.

Two pigeons had access to multiple concurrent schedules of reinforcement for 24 hours per day in their home cages. The variable-interval schedules comprising the multiple concurrent schedules were varied across 16 conditions. In three sets of conditions, one schedule was varied while its concurrent alternative and the concurrent schedules in the other component were held constant. Behavioral contrast was observed; that is, as the rate of reinforcement arranged by the varied schedule decreased, response rates on the constant schedules typically increased. These conditions formed part of two larger sets of conditions in which the concurrent schedules in one multiple-schedule component remained constant while the concurrent schedules in the other component were varied. Successive independence was found, in that behavior allocation during the constant component did not vary as a function of the reinforcer ratios in the varied component. Successive independence between components in multiple concurrent schedules is a robust result that occurs in closed economies and under conditions that promote behavioral contrast.     

A sufficient condition for pooling data

We consider the problems arising from using sequences of experiments to discover the causal structure among a set of variables, none of whom are known ahead of time to be an “outcome”. In particular, we present various approaches to resolve conflicts in the experimental results arising from sampling variability in the experiments. We provide a sufficient condition that allows for pooling of data from experiments with different joint distributions over the variables. Satisfaction of the condition allows for an independence test with greater sample size that may resolve some of the conflicts in the experimental results. The pooling condition has its own problems, but should—due to its generality—be informative to techniques for meta-analysis.     

Combining additive representations on subsets into an overall representation

Many traditional conjoint representations of binary preferences are additively decomposable, or additive for short. An important generalization arises under rank-dependence, when additivity is restricted to cones with a fixed ranking of components from best to worst (comonotonicity), leading to configural weighting, rank-dependent utility, and rank- and sign-dependent utility (prospect theory). This paper provides a general result showing how additive representations on an arbitrary collection of comonotonic cones can be combined into one overall representation that applies to the union of all cones considered. The result is applied to a new paradigm for decision under uncertainty developed by Duncan Luce and others, which allows for violations of basic rationality properties such as the coalescing of events and other framing conditions. Through our result, a complete preference foundation of a number of new models by Luce and others can be obtained. We also show how additive representations on different full product sets can be combined into a representation on the union of these different product sets.     

Bird and the Dispositional Essentialist Account of Spatiotemporal Relations

The basic principles of dispositional essentialism do not require that the fundamental spatiotemporal relations are dispositional in nature. Nevertheless, Bird (who defends dispositional monism) argues that they possess dispositional essences in virtue of the fact that the obtaining of these relations can be characterised by the satisfaction of a certain counterfactual. In this paper I argue that his suggestion fails, and so, despite his attempt, the case of the spatiotemporal relations remains the ‘big bad bug’ for the thesis of dispositional monism.

A Model-Based Approach to Understanding Apraxia in Corticobasal Syndrome

Limb apraxia is a neurological disorder of higher cognitive function characterized by an inability to perform purposeful skilled movements and not attributable to an elementary sensorimotor dysfunction or comprehension difficulty. Corticobasal Syndrome (CBS) is an akinetic rigid syndrome with asymmetric onset and progression with at least one basal ganglia feature (rigidity, limb dystonia or myoclonus) and one cortical feature (limb apraxia, alien hand syndrome or cortical sensory loss). Even though limb apraxia is highly prevalent in CBS (70–80%), very few studies have examined the performance of CBS patients on praxis measures in detail. This review aims to (1) briefly summarize the clinical, neuroanatomical and pathological findings in CBS, (2) briefly outline what limb apraxia is and how it is assessed, (3) to comprehensively review the literature on limb apraxia in CBS to date and (4) to briefly summarize the literature on other forms of apraxia, such as limb-kinetic apraxia and buccofacial apraxia. Overall, the goal of the review is to bring a model-based perspective to the findings available in the literature to date on limb apraxia in CBS.