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Estimating transmission noise on networks from stationary local order
No full textWe study networks of nodes characterised by binary traits that change both endogenously and through nearest-neighbour interaction. Our analytical results show that those traits can be ranked according to the noisiness of their transmission using only measures of order in the stationary state. Crucially, this ranking is independent of network topology. As an example, we explain why, in line with a long-standing hypothesis, the relative stability of the structural traits of languages can be estimated from their geospatial distribution. We conjecture that similar inferences may be possible in a more general class of Markovian systems. Consequently, in many empirical domains where longitudinal information is not easily available the propensities of traits to change could be estimated from spatial data alone.publishe
Integrating animal tracking and trait data to facilitate global ecological discoveries
No full textUnderstanding animal movement is at the core of ecology, evolution and conservation science. Big data approaches for animal tracking have facilitated impactful synthesis research on spatial biology and behavior in ecologically important and human-impacted regions. Similarly, databases of animal traits (e.g. body size, limb length, locomotion method, lifespan) have been used for a wide range of comparative questions, with emerging data being shared at the level of individuals and populations. Here, we argue that the proliferation of both types of publicly available data creates exciting opportunities to unlock new avenues of research, such as spatial planning and ecological forecasting. We assessed the feasibility of combining animal tracking and trait databases to develop and test hypotheses across geographic, temporal and biological allometric scales. We identified multiple research questions addressing performance and distribution constraints that could be answered by integrating trait and tracking data. For example, how do physiological (e.g. metabolic rates) and biomechanical traits (e.g. limb length, locomotion form) influence migration distances? We illustrate the potential of our framework with three case studies that effectively integrate trait and tracking data for comparative research. An important challenge ahead is the lack of taxonomic and spatial overlap in trait and tracking databases. We identify critical next steps for future integration of tracking and trait databases, with the most impactful being open and interlinked individual-level data. Coordinated efforts to combine trait and tracking databases will accelerate global ecological and evolutionary insights and inform conservation and management decisions in our changing world.publishe
Antisemitismus und pro-palästinensische Proteste an deutschen Hochschulen : Befragungsergebnisse bei Studierenden und Hochschulleitungen
No full textpublishe
Bilateral asymmetry in craniofacial structures and kinematics of feeding attacks in the scale-eating cichlid fish, Perissodus microlepis
No full textCichlid fishes are a textbook example for adaptive radiations, since they diversified into several hundred highly specialized species in each of three great East African lakes. Even scale-eating, an extremely specialized feeding mode, evolved independently multiple times in these radiations and in Lake Tanganyika alone, six endemic scale-eating species occupy this extremely specialized ecological niche. Perissodus microlepis went a step further, by evolving bilaterally asymmetrical heads with an intra-specific polymorphism where left- and right-headed morphs predominantly scrape scales from the opposite sides of their prey. While the bilateral asymmetry of scale-eating cichlids has been known, exactly which craniofacial features explain the laterality of the heads remained unclear. Here we aimed, by utilizing micro-computed tomography (μCT), to resolve this issue of how bilateral symmetry in the skeletal structure is broken in scale-eating Perissodus. Our 3D geometric morphometrics analysis clearly separated and identified the two groups of either left- or right-headed fish. In addition, we observed consistent asymmetric volume changes in the premaxilla, maxilla, and mandible of the craniofacial structures, where left-headed fish have larger jaw elements on the right side, and vice versa. The bimodality implies that the effect sizes of environmental factors might be minor while genetics might be responsible to a larger extent for the asymmetry observed in their head morphology. High-speed video analyses of attacks by asymmetrical morphotypes revealed that they utilize their asymmetrical mouth protrusion, as well as lateralized behavior, to re-orientate the gape towards the preferred side of their prey fish to more efficiently scrape scales.publishe
Neural Rhythms of Cooperation : Exploring How Our Brains Play Together
No full textCooperation is a cornerstone of human interaction. Extensive research across the human sciences suggests that human evolutionary success is not merely driven by general intelligence but rather by advanced social coordination abilities. At the heart of these abilities lies collective intentionality, enabling individuals to align their actions toward shared goals and shaping the foundations of social organization. Social neuroscience provides an interdisciplinary framework to examine the neural mechanisms supporting cooperative behavior. This dissertation adopts a process perspective, emphasizing collaborative role taking as a fundamental organizing principle of human cooperation. For this purpose, we developed a dyadic Pacman Game, designed to create a naturalistic yet experimentally controlled social environment by systematically modifying game rules. In this game, players work together to navigate a Pacman through a maze using an agreed-upon coding system based on pictorial cues. Each game move requires two sequential turns, with players alternating between the roles of sender and receiver of two symbolic picture cues. Across three studies, we examined whether neural markers well-established in cognitive and affective neuroscience could reliably track collaborative role taking during gameplay.
The first study introduced the Pacman Game as a novel process-oriented experimental paradigm. Participants played the game in dyads while undergoing simultaneous high-density EEG recording. We explored whether event-related potentials (ERPs) could serve as real-time neural indicators of role taking during collaboration. Our findings revealed that larger P3 amplitudes reflected higher informational value for receivers compared to senders of picture cues. Additionally, a distinct late positivity emerged, differentiating whether the receiver’s role was tied to cognitively demanding decision-making or affectively significant action monitoring. Notably, similar effects were observed when participants played with a computerized game partner, suggesting that experimental games may motivate humans to similarly cooperate with an artificial agent.
The second study expanded upon the ERP analysis by incorporating spectral analysis to examine induced (non-phase-locked) oscillatory activity linked to collaborative role-taking. We observed distinct changes in alpha to lower beta power associated with player roles, with a pronounced power decrease when receiving compared to sending picture cues. This effect was more pronounced when the receiver role involved heightened cognitive and semantic processing demands. Again, effects were similar when participants played the Pacman Game with human or computer partners. Importantly, we replicated key ERP findings, including a larger P3 component for receivers compared to senders and a late positivity indexing the cognitive demands of specific player roles.
The third study addressed the idea that shared goals often carry different importance for the collaborators. To test this, we integrated a monetary gamble into the Pacman Game to systematically influence players’ personal motivation. Our findings showed that enriching shared goals with personal rewards elicited neural signatures of reward processing including positive fronto-central ERP components (RewP, P3, LPP) and induced power increases in delta to theta band oscillations. Furthermore, the study replicated the ERP and oscillatory effects from the previous studies, reinforcing the robustness of our findings.
Overall, these studies reveal how dynamic shifts in collaborative roles are systematically reflected in ERP and oscillatory brain activity during cooperative tasks, providing neural insights into the mechanisms of joint action and coordination. The Pacman Game exemplifies the potential of process-oriented experimental paradigms for studying the psychological foundations underlying cooperative behavior. By bridging the gap between highly controlled laboratory studies and real-world social interactions, such games offer a promising avenue for future research in social neuroscience.publishe
Access denied : Land alienation and pastoral conflicts
No full textConflicts involving pastoralists have been on the rise in the past two decades in West, Central and East Africa. This article argues that land alienation is a major source of this type of violence. We employ a narrow identification strategy of relevant pastoral conflicts based on the Armed Conflict Location Event Dataset and create a unique indicator of land alienation comprised of three types of land use changes (conversion of land into conservation areas, crop farms, and industrial mining projects). Relying on a disaggregated quantitative comparative design of 50 km-by-50 km cells covering the Sahelian region from 2002 to 2019, we find that land alienation is an underlying cause of pastoral conflicts. Moreover, we show that the impact of land alienation on pastoralist violence spreads over long distances and is influenced by state presence and climatic conditions. Our analysis further reveals an overlap between pastoralist violence and armed conflict. Bridging a gap between macro- and micro-level studies, we contribute to shed more light on the determinants of pastoral conflicts, a type of violence that has received scant attention in the geospatial quantitative literature.publishe
Improving Parent-Child Interaction and Reducing Parental Violent Discipline : a Multi-Informant Multi-Method Pilot Feasibility Study of a School-Based Intervention
No full textPurposeGlobally, many children are exposed to violent discipline in multiple settings. Interventions to prevent violent discipline are therefore highly needed. In the present study, the feasibility of the intervention Interaction Competencies with Children – for Parents (ICC-P), an additional module of a school-based intervention for teachers, was tested. The intervention aims to prevent violent discipline by changing attitudes towards such method and fostering supportive adult-child interaction through non-violent interaction skills.MethodsIn total, 164 parents (Mage= 39.55, range = 24 70, 72.3% female) from four public secondary schools in Tanzania participated in a four-day training conducted by six trainers (Mage= 44.67, range = 40–47, 50% female). Using a One-Group Pre-Post design, we measured the feasibility and preliminary effectiveness of the intervention qualitatively and quantitatively. Parents were assessed via self-administered questionnaires before and six weeks after the intervention. Trainers rated the implementation of every workshop session.ResultsBased on descriptive statistics and Classical Content Analysis, implementing trainers and participants rated ICC-P as feasible. Participants indicated a high need for such interventions and showed high acceptance. They were able to integrate core aspects of the intervention in their daily interactions with children. Using t-tests, ICC-P proved to be preliminarily effective; parents reported applying less violent discipline and holding more critical attitudes about such measures after the intervention.ConclusionICC-P is feasible intervention that showed initial signs of effectiveness. We recommend combining the parents’ training module with the teachers’ module to prevent violence in multiple settings.publishe
Bonobo (Pan paniscus) Density and Distribution in Central Africa's Largest Rainforest Reserve : Long-term Survey Data Show Pitfalls in Methodological Approaches and Call for Vigilance
No full textConservation measures require accurate estimates of density and abundance and population trend assessments. The bonobo (Pan paniscus) is considered Endangered in the IUCN Red List. This classification assumes that available population data are representative. However, with only 30% of the bonobo’s historic geographical range surveyed, reliable information is needed to assess the species' population status. Here, we use information from 13 surveys conducted between 2002 and 2018 in an area of 42,000 km2, representing ~27% of bonobo-suitable habitat: Salonga National Park and its corridor, Democratic Republic of the Congo (DRC). Using 8310 km of reconnaissance and transect walks and 27,045 days of camera trapping, we: (1) provide updated estimates of bonobo population density and distribution (42,000 km2; ~5,000 km2 of which, to the best of our knowledge, have not been surveyed before by scientists), (2) assess population trends (15,758 km2; 2002–2008 vs 2012–2018), (3) compare estimates obtained with different methods, and (4) assess the factors driving bonobo density and distribution. Although we detected a non-significant population decline, our study suggests that Salonga is a bonobo stronghold, with a population ranging between 8244 and 18,308 mature individuals (density: 0.31 individuals/km2). Standing crop nest counts returned non-significantly lower density estimates than camera trap distance sampling. Nest count-estimates were higher in areas with Marantaceae understorey and those farther away from rivers, while camera trap-estimates were higher in areas with lower human presence. Regardless of the method, bonobos were rarer in proximity to villages. They occurred more often in areas of dense forest cover and in proximity to ranger posts. Our results point towards a declining bonobo population in Salonga, but do not provide sufficient evidence to confirm this statistically. Consequently, the continued monitoring of the bonobo population and preservation of the integrity of Salonga, considering its biological and cultural heritage, will be crucial in the preservation of this stronghold of wild bonobos.publishe