Converse Ackermann Croperty and semiclassical negation

A prepositional logic S has the Converse Ackermann Property (CAP) if (AB)C is unprovable in S when C does not contain . In A Routley-Meyer semantics for Converse Ackermann Property (Journal of Philosophical Logic, 16 (1987), pp. 65–76) I showed how to derive positive logical systems with the CAP. There I conjectured that each of these positive systems were compatible with a so-called semiclassical negation. In the present paper I prove that this conjecture was right. Relational Routley-Meyer type semantics are provided for each one of the resulting systems (the positive systems plus the semiclassical negation).     

Phonetic awareness and reading acquisition

Summary Three issues are dealt with: the relationship between phonetic awareness and reading acquisition, the nature of the cognitive capacities that make phonetic awareness possible, and the potential influence of phonetic awareness on language perception and comprehension. Data on the relationships between phonetic awareness and reading acquisition support an interactive view. For most people, learning to read in the alphabetic system stimulates phonetic awareness. On the other hand, phonetic awareness is a critical factor for success in reading acquisition. Indications about the nature of the cognitive capacities that underlie phonetic awareness may be obtained by inspecting its development. Two capacities at least seem to be required: the capacity to ignore meaning and focus on the sound properties of speech and the capacity of segmentation.Lack of phonetic awareness does not imply that phonetic processing does not take place during speech perception. Recent data suggest that speech perception includes a stage of extraction of phonetic features regardless of whether or not the subject is able to segment speech into phones explicitly. However, phonetic awareness may influence perceptual strategies and the relative weight of meaning expectancies in identification.Our work received support from the Belgian Fonds de la Recherche fondamentale collective (F.R.F.C.) under contracts No. 2.4505.76 and 2.4505.80 as well as from the Belgian Ministère de la Politique et de la Programmation scientifiques (Action de Recherche concertée Processus cognitifs dans la lecture)     

Correlation coefficients for more than one scale type: An alternative to the Janson and Vegelius approach

Janson and Vegelius have recently suggested a family of correlations for variables of mixed scale types, including nominal scales. The resulting correlations areE-coefficients, which means that they are unity if the variables involved are identical up to permissible transformations, and that they can be considered as inner products in a Euclidian space. Some of the coefficients of the correlation family suggested by Janson and Vegelius are generalized squared product-moment correlations and some are not. In the present paper, a family of correlations for variables of mixed scale types is advocated all members of which are generalized squared product-moment correlations. Some practical advantages of the latter family are explained. The authors are obliged to Klaas Nevels and Henk Kiers for helpful comments.     

On the equivalence of two oblique congruence rotation methods,and orthogonal approximations

Tucker's method of oblique congruence rotation is shown to be equivalent to a procedure by Meredith. This implies that Monte Carlo studies on congruence by Nesselroade, Baltes and Labouvie and by Korth and Tucker are highly comparable. The problem of rotating two matrices orthogonally to maximal congruence has not yet been solved. An approximate solution to this problem can be derived from Tucker's method. Even better results can be obtained from a Procrustes rotation followed by rotation to simple structure.     

Network Connectivity Dynamics,Cognitive Biases,and the Evolution of Cultural Diversity in Round-Robin Interactive Micro-Societies

The distribution of cultural variants in a population is shaped by both neutral evolutionary dynamics and by selection pressures. The temporal dynamics of social network connectivity, that is, the order in which individuals in a population interact with each other, has been largely unexplored. In this paper, we investigate how, in a fully connected social network, connectivity dynamics, alone and in interaction with different cognitive biases, affect the evolution of cultural variants. Using agent-based computer simulations, we manipulate population connectivity dynamics (early, mid, and late full-population connectivity); content bias, or a preference for high-quality variants; coordination bias, or whether agents tend to use self-produced variants (egocentric bias), or to switch to variants observed in others (allocentric bias); and memory size, or the number of items that agents can store in their memory. We show that connectivity dynamics affect the time-course of variant spread, with lower connectivity slowing down convergence of the population onto a single cultural variant. We also show that, compared to a neutral evolutionary model, content bias accelerates convergence and amplifies the effects of connectivity dynamics, while larger memory size and coordination bias, especially egocentric bias, slow down convergence. Furthermore, connectivity dynamics affect the frequency of high-quality variants (adaptiveness), with late connectivity populations showing bursts of rapid change in adaptiveness followed by periods of relatively slower change, and early connectivity populations following a single-peak evolutionary dynamic. We evaluate our simulations against existing data collected from previous experiments and show how our model reproduces the empirical patterns of convergence.