Systems of bounded rational agents with information-theoretic constraints

Specialization and hierarchical organization are important features of efficient collaboration in economical, artificial, and biological systems. Here, we investigate the hypothesis that both features can be explained by the fact that each entity of such a system is limited in a certain way. We propose an information-theoretic approach based on a Free Energy principle, in order to computationally analyze systems of bounded rational agents that deal with such limitations optimally. We find that specialization allows to focus on fewer tasks, thus leading to a more efficient execution, but in turn requires coordination in hierarchical structures of specialized experts and coordinating units. Our results suggest that hierarchical architectures of specialized units at lower levels that are coordinated by units at higher levels are optimal, given that each unit's information-processing capability is limited and conforms to constraints on complexity costs.Comment: 35 pages, 12 figure

The Angolan bushveld lizards, genus Heliobolus Fitzinger, 1843 (Squamata: Lacertidae): Integrative taxonomy and the description of two new species

The genus Heliobolus comprises four recognized species, all endemic to sub-Saharan Africa. Of these, only Heliobolus lugubris occurs in southern Africa, its distribution extending from Angola in the west to Mozambique in the east and reaching as far south as parts of northern South Africa. Like many of the reptile species that occur in southern Africa, Heliobolus lugubris is poorly studied, and preliminary investigation suggested that it may contain cryptic diversity. The present work focusses on the Angolan population of H. lugubris and uses an integrative taxonomic approach based on morphological, coloration and DNA sequence data. The results indicate that some of the current and historical specimens of H. lugubris from Angola do not correspond to the nominotypical form, and that differences between specimens suggest the presence of two additional species, described here as Heliobolus bivari sp. nov. from the southernmost xeric/desertic regions and plateau of Namibe Province, southwestern Angola and H. crawfordi sp. nov. from the Serra da Neve inselberg north through the sub-desert coastal regions of northern Namibe, Benguela, and Kwanza Sul provinces. Nominotypical Heliobolus lugubris is confirmed to occur in Cuando Cubango Province, southeastern Angola