Humans commonly engage in a variety of search behaviours, for example when looking for an object, a partner, information, or a solution to a complex problem. The success or failure of a search strategy crucially depends on the structure of the environment and the constraints it imposes on the individuals. Here we focus on environments in which individuals have to explore the solution space gradually and where their reward is determined by one unique solution...
Both normative and many descriptive theories of decision making under risk are based on the notion that outcomes are weighted by their probability, with subsequent maximization of the (subjective) expected outcome. Numerous investigations from psychology, economics, and neuroscience have produced evidence consistent with this notion. However, this research has typically investigated choices involving relatively affect-poor, monetary outcomes. We compared choice in relatively affect-poor, monetary lottery problems with choice in relatively affect-rich medical decision problems. Computational...
In temporal discounting, animals trade off the time to obtain a reward against the quality of a reward, choosing between a smaller reward available sooner versus a larger reward available later. Similar discounting can apply over space, when animals choose between smaller and closer versus larger and more distant rewards. Most studies of temporal and spatial discounting in nonhuman animals use food as the reward, and it is not established whether animals trade off other...
Analyses of the evolution of cooperation often rely on two simplifying assumptions: (i) individuals interact equally frequently with all social network members and (ii) they accurately remember each partner's past cooperation or defection. Here, we examine how more realistic, skewed patterns of contact---in which individuals interact primarily with only a subset of their network's members---influence cooperation. In addition, we test whether skewed contact patterns can counteract the decrease in cooperation caused by memory errors (i.e.,...
Data from: Parasite-infected sticklebacks increase the risk-taking behavior of uninfected group membersNicolle Demandt, Benedikt Saus, Ralf H.J.M. Kurvers, Jens Krause, Joachim Kurtz, Jörn P. Scharsack & Ralf H. J. M. Kurvers
Trophically transmitted parasites frequently increase their hosts' risk-taking behaviour, to facilitate transmission to the next host. Whether such elevated risk-taking can spill over to uninfected group members is, however, unknown. To investigate this, we confronted groups of six three-spined sticklebacks, Gasterosteus aculeatus, containing 0, 2, 4 or 6 experimentally infected individuals with a simulated bird attack and studied their risk-taking behaviour. As a parasite, we used the tapeworm Schistocephalus solidus, which increases the risk-taking of...
What are the dynamics and regularities underlying social contact, and how can contact with the people in one's social network be predicted? In order to characterize distributional and temporal patterns underlying contact probability, we asked 40 participants to keep a diary of their social contacts for 100 consecutive days. Using a memory framework previously used to study environmental regularities, we predicted that the probability of future contact would follow in systematic ways from the frequency,...
Data from: Proto-cooperation: group hunting sailfish improve hunting success by alternating attacks on grouping preyJames E. Herbert-Read, Pawel Romanczuk, Stefan Krause, Daniel Strömbom, Pierre Couillaud, Paolo Domenici, Ralf H.J.M. Kurvers, Stefano Marras, John F. Steffensen, Alexander D.M. Wilson, Jens Krause, Alexander D. M. Wilson & Ralf H. J. M. Kurvers
We present evidence of a novel form of group hunting. Individual sailfish (Istiophorus platypterus) alternate attacks with other group members on their schooling prey (Sardinella aurita). While only 24% of attacks result in prey capture, multiple prey are injured in 95% of attacks, resulting in an increase of injured fish in the school with the number of attacks. How quickly prey are captured is positively correlated with the level of injury of the school, suggesting...
Standard models of intertemporal choice assume that individuals discount future payoffs by integrating reward amounts and time delays to generate a discounted value. Alternative models propose that, rather than integrate across them, individuals compare within attributes (amounts and delays) to determine if differences in one attribute outweigh differences in another attribute. For instance, the similarity model 1) compares the two reward amounts to determine whether they are similar, 2) compares the similarity of the two...
Max Planck Institute for Human Development8
University of Nebraska–Lincoln3
University of Münster1
Leibniz Institute of Freshwater Ecology and Inland Fisheries1
University of Oslo1
University of Copenhagen1
University of Sydney1
University of Applied Sciences1
Norwegian Institute of Public Health1