Spatial Attention is Driven by Mental Simulations

Introduction: Many studies have shown that task performance is affected by the relation between the spatial location and the meaning of a target word. These effects have been obtained for object names that have typical positions in the physical world (Zwaan and Yaxley, 2003; Bergen et al., 2007; Šeticˇ and Domijan, 2007; Estes et al., 2008) and for concepts that are metaphorically related to spatial position (Richardson et al., 2003; Meier and Robinson, 2004; Schnall and Clore, 2004; Schubert, 2005; Giessner and Schubert, 2007; Casasanto, 2009; Van Dantzig, 2009). Although these findings are consistent with a mental simulation account, at least some of the interactions between meaning and spatial location might be explained by polarity alignment. In our study (Pecher et al., 2010) we tested whether spatial congruency effects are best explained by mental simulations or by polarity alignment. ..

Equilibrium spherically curved 2D Lennard-Jones systems

To learn about basic aspects of nano-scale spherical molecular shells during their formation, spherically curved two-dimensional N-particle Lennard-Jones systems are simulated, studying curvature evolution paths at zero-temperature. For many N-values (N<800) equilibrium configurations are traced as a function of the curvature radius R. Sharp jumps for tiny changes in R between trajectories with major differences in topological structure correspond to avalanche-like transitions. For a typical case, N=25, equilibrium configurations fall on smooth trajectories in state space which can be traced in the E-R plane. The trajectories show-up with local energy minima, from which growth in N at steady curvature can develop.Comment: 10 pages, 2 figures, to be published in Journal of Chemical Physic

Unconstraining theories of embodied cognition

The approach/avoidance effect refers to the finding that valenced stimuli trigger approach and avoidance actions. Markman and Brendl (2005) argued that this effect is not a truly embodied phenomenon, but depends on participants’ symbolic representation of the self. In their study, participants moved valenced words toward or away from their own name on the computer screen. This would induce participants to form a ‘disembodied’ selfrepresentation at the location of their name, outside of the body. Approach/avoidance effects occurred with respect to the participant’s name, rather than with respect to the body. In three experiments, we demonstrate that similar effects are found when the name is replaced by a positive word, a negative word or even when no word is resented at all. This suggests that the ‘disembodied self’ explanation of Markman and Brendl is incorrect, and that their findings do not necessarily constrain embodied theories of cognition

An electric charge has no screw sense--a comment on the twistfree formulation of electrodynamics by da Rocha & Rodrigues

Da Rocha and Rodigues (RR) claim (i) that in classical electrodynamics in vector calculus the distinction between polar and axial vectors and in exterior calculus between twisted and untwisted forms is inappropriate and superfluous, and (ii) that they can derive the Lorentz force equation from Maxwell's equations. As to (i), we point out that the distinction of polar/axial and twisted/untwisted derives from the property of the electric charge of being a pure scalar, that is, not carrying any screw sense. Therefore, the mentioned distinctions are necessary ingredients in any fundamental theory of electrodynamics. If one restricted the allowed coordinate transformations to those with positive Jacobian determinants (or prescribed an equivalent constraint), then the RR scheme could be accommodated; however, such a restriction is illegal since electrodynamics is, in fact, also covariant under transformations with negative Jacobians. As to (ii), the "derivation" of the Lorentz force from Maxwell's equations, we point out that RR forgot to give the symbol F (the field strength) in Maxwell's equations an operational meaning in the first place. Thus, their proof is empty. Summing up: the approach of RR does not bring in any new insight into the structure of electrodynamics.Comment: Added answer to da Rocha & Rodrigues arXiv:0912.212

De forten en kastelen van Ghana een collectief monument

In the colonial history or the history of European expansion like one prefers to call her nowadays the trade forts which have been built in the course of times on Africa's west coast and especially on the Gold coast, play an important role. Ten years before Columbus discovered America the castle Sao Jorge da Mina was built by the Portuguese on a spit of land in Elmina, which already for some time was an important market where merchants from the deep interior exchanged gold and draperies from the Mediterranean area against salt and smoked fish. Soon it appeared that these African merchants coming with their goods along the caravan routes through the Sahara to Elmina could not compete with the Portuguese. They had to make way for the 'Akannists' who exchanged gold, ivory and other wood products for Portuguese goods. To be able to draw off the gold stream even better the Portuguese still built two or three other fortified trade posts and till ca. 1600 they could monopolize that trade. However that changed when the Dutch built a little fort in Mori on a special request of the local sovereign whose subjects regularly were exposed to reprisals of the Portuguese because of their 'illegal' trade with the Dutch. With this the first step had been done for the proliferation of trade forts on the Gold coast. Soon a sort of international gold-rush was developed and before the 17th century was over Dutch, Englishmen, Danes, Swedes, Brandenburgers and French had built more than thirty fortified trade posts on a coastal strip less than 300 km long. Each fort formed the terminus of one of the ramifications of the main trade routes from the interior. The sharpest trade practices were used at the competition with the European neighbour, who sometimes had lodged himself within range of an already existing fort. This way a sort of West-African ‘shopping street’ of forts and castles came into existence, where during many centuries African and European merchants bartered with each other on a footing of equality. The Europeans only were hirers of the soil their forts stood on and had no power outside the walls of their establishments. That one also dealt in slaves next to gold and ivory does not alter this fact. About twenty of these buildings are left, some in a ruinous, others in a reasonably well condition. Some are beautifully situated, others are less interesting. But as a whole they form a collective monument of a piece of world history wherein three continents were involved at the same time, the famous triangular trade which left behind a deep track of wealth and perdition

De forten en kastelen van Ghana een collectief monument

In the colonial history or the history of European expansion like one prefers to call her nowadays the trade forts which have been built in the course of times on Africa's west coast and especially on the Gold coast, play an important role. Ten years before Columbus discovered America the castle Sao Jorge da Mina was built by the Portuguese on a spit of land in Elmina, which already for some time was an important market where merchants from the deep interior exchanged gold and draperies from the Mediterranean area against salt and smoked fish. Soon it appeared that these African merchants coming with their goods along the caravan routes through the Sahara to Elmina could not compete with the Portuguese. They had to make way for the 'Akannists' who exchanged gold, ivory and other wood products for Portuguese goods. To be able to draw off the gold stream even better the Portuguese still built two or three other fortified trade posts and till ca. 1600 they could monopolize that trade. However that changed when the Dutch built a little fort in Mori on a special request of the local sovereign whose subjects regularly were exposed to reprisals of the Portuguese because of their 'illegal' trade with the Dutch. With this the first step had been done for the proliferation of trade forts on the Gold coast. Soon a sort of international gold-rush was developed and before the 17th century was over Dutch, Englishmen, Danes, Swedes, Brandenburgers and French had built more than thirty fortified trade posts on a coastal strip less than 300 km long. Each fort formed the terminus of one of the ramifications of the main trade routes from the interior. The sharpest trade practices were used at the competition with the European neighbour, who sometimes had lodged himself within range of an already existing fort. This way a sort of West-African ‘shopping street’ of forts and castles came into existence, where during many centuries African and European merchants bartered with each other on a footing of equality. The Europeans only were hirers of the soil their forts stood on and had no power outside the walls of their establishments. That one also dealt in slaves next to gold and ivory does not alter this fact. About twenty of these buildings are left, some in a ruinous, others in a reasonably well condition. Some are beautifully situated, others are less interesting. But as a whole they form a collective monument of a piece of world history wherein three continents were involved at the same time, the famous triangular trade which left behind a deep track of wealth and perdition