Rule Representation in Explicit Categorization

One defining characteristic of human behavior is the ability to select an appropriate action in an entirely novel situation. How abstract rules are represented in the brain, and how these representations operate on internal models of the world to generate flexible rapidly optimized behaviors remains an open question in neuroscience as well as computer science. The hallmark of quickly optimized flexibility inherent to explicit behavioral rules has lead to the assumption that these rules are based on high level abstractions. In the recent past, behavioral measurements in the human psychophysics literature were linked to predictions at the processing level and the convenient mathematical construct of a decision criterion has precipitated in several cognitive process models. However, the assumption that higher order decision processes involve comparisons to some internal criterion is not trivial and was investigated. This thesis provides evidence to falsify the criterion as a processing component in human decision making and offers fundamental insights to reverse engineer decision processes in the brain. Cognitive flexibility and rule guided behavior appear to rely on phylogenetically advanced extrapolation processes that are mediated by dynamic feed-forward and feed-back circuits, which continually update internal and external information to support goal directed behavior

Measurement of Inclusive and Dijet D* Meson Cross Sections in Photoproduction at HERA

The inclusive photoproduction of D * mesons and of D *-tagged dijets is investigated with the H1 detector at the ep collider HERA. The kinematic region covers small photon virtualities Q 21. 8 GeV. The heavy quark production process is further investigated in events with at least two jets with transverse momentum p T(jet)>3. 5 GeV each, one containing the D * meson. Differential cross sections for D *-tagged dijet production and for correlations between the jets are measured in the range {pipe}η(D *){pipe}<1. 5 and p T(D *)<2. 1 GeV. The results are compared with predictions from Monte Carlo simulations and next-to-leading order perturbative QCD calculations. © 2012 The Author(s).0SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Search for odderon induced contributions to exclusive pi0 photoproduction at HERA

A search for contributions to the reaction ep-> e pi^0 N^* from photon-Odderon fusion in the photoproduction regime at HERA is reported, at an average photon-proton centre-of-mass energy = 215 GeV. The measurement proceeds via detection of the pi^0 decay photons, a leading neutron from the N^* decay, and the scattered electron. No pi^0 signal is observed and an upper limit on the cross section for the photon-Odderon fusion process of sigma(gamma p -> pi^0 N^*) < 49 nb at the 95% confidence level is derived, integrated over the experimentally accessible range of the squared four-momentum transfer at the nucleon vertex 0.02 < |t| < 0.3 Gev^2. This excludes a recent prediction from a calculation based on a non-perturbative QCD model of a photon-Odderon fusion cross section above 200 nb.Comment: 13 pages, 1 table and 4 figure