Ralf Kurvers

Ralf Kurvers
Max Planck Institute for Human Development | MPIB · Center of Adaptive Rationality

About

100
Publications
19,301
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2,002
Citations
Additional affiliations
October 2011 - December 2014
Leibniz-Institute of Freshwater Ecology and Inland Fisheries
Position
  • PostDoc Position

Publications

Publications (100)
Article
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People routinely rely on experts’ advice to guide their decisions. However, experts are known to make inconsistent judgments when judging the same case twice. Previous research on expert inconsistency has largely focused on individual or situational factors; here we focus directly on the cases themselves. First, using a theoretical model, we study...
Preprint
Resource availability and sociality are tightly coupled. Sociality facilitates resource access in a wide range of animal species. Simultaneously, resource availability may change sociality. However, experimental evidence for resource-driven social changes in the wild, beyond local aggregations at the resource, remains scarce. Moreover, it is largel...
Article
Full-text available
Misinformation presents a significant societal problem. To measure individuals’ susceptibility to misinformation and study its predictors, researchers have used a broad variety of ad-hoc item sets, scales, question framings, and response modes. Because of this variety, it remains unknown whether results from different studies can be compared (e.g.,...
Article
Full-text available
Cognitive biases are widespread in humans and animals alike, and can sometimes be reinforced by social interactions. One prime bias in judgment and decision-making is the human tendency to underestimate large quantities. Previous research on social influence in estimation tasks has generally focused on the impact of single estimates on individual a...
Article
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Digital disruptions caused by use of technologies like social media arguably present a formidable challenge to democratic values and in-turn to Collective Intelligence (CI or “wisdom-of-crowd”), which the former is an emblem of. These challenges such as misinformation, partisan bias, polarization, and rising mistrust in institutions (incl. mainstre...
Article
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A key benefit of sociality is a reduction in predation risk. Cohesive group behaviour and rapid collective decision making are essential for reducing predation risk in groups. Parasite infection might reduce an individuals’ grouping behaviours and thereby change the behaviour of the group as a whole. To investigate the relationship between parasite...
Article
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Competition for social influence is a major force shaping societies, from baboons guiding their troop in different directions, to politicians competing for voters, to influencers competing for attention on social media. Social influence is invariably a competitive exercise with multiple influencers competing for it. We study which strategy maximize...
Article
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The recent developments of social networks and recommender systems have dramatically increased the amount of social information shared in human communities, challenging the human ability to process it. As a result, sharing aggregated forms of social information is becoming increasingly popular. However, it is unknown whether sharing aggregated info...
Preprint
Balancing the costs of alternative decisions is a fundamental challenge for decision makers. This is especially critical in social situations, where the choices individuals face are often associated with highly asymmetric error costs---such as pedestrian groups crossing the street, police squads holding a suspect at gunpoint, or animal groups evadi...
Article
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Decision makers in contexts as diverse as medical, judicial and political decision making are known to differ substantially in response bias and accuracy, and these differences are a major factor undermining the reliability and fairness of the respective decision systems. Using theoretical modelling and empirical testing across five domains, we sho...
Preprint
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A key question individuals face in any social learning environment is when to innovate alone and when to imitate others. Previous simulation results have found that the best performing groups exhibit an intermediate balance, yet it is still largely unknown how individuals collectively negotiate this balance. We use an immersive collective foraging...
Article
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Sociality is a fundamental organizing principle across taxa, thought to come with a suite of adaptive benefits. However, making causal inferences about these adaptive benefits requires experimental manipulation of the social environment, which is rarely feasible in the field. Here we manipulated the number of conspecifics in Trinidadian guppies (Po...
Article
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Social information use is widespread in the animal kingdom, helping individuals rapidly acquire useful knowledge and adjust to novel circumstances. In humans, the highly interconnected world provides ample opportunities to benefit from social information but also requires navigating complex social environments with people holding disparate or confl...
Article
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Many prey species have evolved collective responses to avoid predation. They rapidly transfer information about potential predators to trigger and coordinate escape waves. Predation avoidance behaviour is often manipulated by trophically transmitted parasites, to facilitate their transmission to the next host. We hypothesized that the presence of i...
Article
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Antibiotic overprescribing is a global challenge contributing to rising levels of antibiotic resistance and mortality. We test a novel approach to antibiotic stewardship. Capitalising on the concept of “wisdom of crowds”, which states that a group’s collective judgement often outperforms the average individual, we test whether pooling treatment dur...
Preprint
Competition for social influence is a major force shaping societies. Strategies that maximize social influence are, however, poorly understood. Applying game theory to a scenario where two advisers compete for a client, we find that the rational solution for advisers is to report truthfully when favoured by the client, but to exaggerate or blatantl...
Preprint
Full-text available
Sociality is a fundamental organizing principle across taxa, thought to come with a suite of adaptive benefits. However, making causal inferences about these adaptive benefits requires experimental manipulation of the social environment, which is rarely feasible in the field. Here we manipulated the number of conspecifics in Trinidadian guppies (Po...
Article
Billfishes are well-known for their distinctive elongated rostra, a.k.a. bills. The functional significance of billfish rostra has been frequently discussed and the recent discovery of an oil gland (glandula oleofera) at the base of the rostrum in swordfish, Xiphias gladius , has added an interesting facet to this discussion regarding the potential...
Article
Full-text available
Whether getting vaccinated, buying stocks, or crossing streets, people rarely make decisions alone. Rather, multiple people decide sequentially, setting the stage for information cascades whereby early-deciding individuals can influence others’ choices. To understand how information cascades through social systems, it is essential to capture the dy...
Preprint
Full-text available
Over the last decades, the relative benefits and costs of individual vs. collective decision-making systems have attracted ample attention in the behavioural sciences and beyond. This research however, has almost exclusively focused on accuracy as a performance criterion, neglecting another major performance dimension of decision-making systems, th...
Article
Social relationships can have important fitness consequences. Although there is increasing evidence that social relationships carry over across contexts, few studies have investigated whether relationships formed early in life are carried over to adulthood. For example, juveniles of monogamous species go through a major life history stage transitio...
Preprint
Full-text available
The digital revolution has fundamentally changed social information exchange and vastly increased exposure to the opinions of others. However, it is unclear whether exchanging such large amounts of information benefits decision making. Exchanging a moderate amount or aggregated forms of social information may indeed avoid information overload and f...
Preprint
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Our increasingly interconnected world provides virtually unlimited opportunities to observe the behavior of others. This affords abundant useful information but also requires navigating complex social environments with people holding disparate or conflicting views. It is, however, still largely unclear how people integrate information from multiple...
Article
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Linking morphological differences in foraging adaptations to prey choice and feeding strategies has provided major evolutionary insights across taxa. Here, we combine behavioural and morphological approaches to explore and compare the role of the rostrum (bill) and micro-teeth in the feeding behaviour of sailfish (Istiophorus platypterus) and strip...
Preprint
Full-text available
Whether getting vaccinated, buying stocks, or crossing streets, people rarely make decisions alone. Rather, multiple people decide sequentially, setting the stage for information cascades whereby early-deciding individuals can influence others' choices. To understand how information cascades through social systems, it is essential to capture the dy...
Article
Full-text available
Distinguishing between high- and low-performing individuals and groups is of prime importance in a wide range of high-stakes contexts. While this is straightforward when accurate records of past performance exist, these records are unavailable in most real-world contexts. Focusing on the class of binary decision problems, we use a combined theoreti...
Preprint
Full-text available
Social bonds can have important fitness consequences. Although there is increasing evidence that social bonds carry over across contexts, few studies have investigated whether social bonds formed early in life are carried over to adulthood. For example, juveniles of monogamous species go through a major life-history stage transition, pair formation...
Preprint
Full-text available
Collective decision making is ubiquitous across biological systems. However, biases at the individual level can impair the quality of collective decisions. One prime bias is the human tendency to underestimate quantities. We performed estimation experiments in human groups, in which we re-wired the structure of information exchange, favouring the e...
Preprint
Full-text available
Experts regularly make inconsistent judgments when judging the same case twice. Previous research on expert inconsistency has focused largely on individual or situational factors. Here we focus directly on the cases themselves. First, using a theoretical model, we study how inconsistency and confidence are affected by how strongly experts agree abo...
Article
Full-text available
Responding to the information provided by others is an important foraging strategy in many species. Through social foraging, individuals can more efficiently find unpredictable resources and thereby increase their foraging success. When individuals are more socially responsive to particular phenotypes than others, however, the advantage they obtain...
Article
Social information enables individuals to reduce uncertainty and increase decision accuracy across a broad range of domains. Intriguingly, individuals and populations consistently differ in social information use. Understanding the underlying causes of this variation has proven challenging due to the lack of a standardized paradigm to quantify soci...
Article
Full-text available
Collective decision-making is ubiquitous, and majority-voting and the Condorcet Jury Theorem pervade thinking about collective decision-making. Thus, it is typically assumed that majority-voting is the best possible decision mechanism, and that scenarios exist where individually-weak decision-makers should not pool information. Condorcet and its ap...
Preprint
Full-text available
Distinguishing between high- and low-performing individuals and groups is of prime importance in a wide range of high-stakes contexts. While this is straightforward when accurate records of past performance exist, in most real-world contexts, such records are unavailable. Focusing on the class of binary decision problems, we use a combined theoreti...
Preprint
Full-text available
BioRxiv link to article: https://doi.org/10.1101/478537 When individuals are more socially responsive to one sex than the other, the benefits they get from foraging socially are likely to depend on the sex composition of the social environment. We tested this hypothesis by performing experimental manipulations of guppy, Poecilia reticulata, sex co...
Article
Full-text available
Individual foraging is under strong natural selection. Yet, whether individuals differ consistently in their foraging success across environments, and which individual- and population-level traits might drive such differences, is largely unknown. We addressed this question in a field experiment, conducting over 1,100 foraging trials with subpopulat...
Article
Full-text available
Artificial light at night (ALAN) is a major form of anthropogenic pollution. ALAN is well known to affect different behaviours during nighttime, when changes in light conditions often have immediate consequences for the trade-offs individuals experience. How ALAN affects daytime behaviours, however, has received far less attention. Here we studied...
Preprint
Full-text available
Majority-voting and the Condorcet Jury Theorem pervade thinking about collective decision-making. Thus, it is typically assumed that majority-voting is the best possible decision mechanism, and that scenarios exist where individually-weak decision-makers should not pool information. Condorcet and its applications implicitly assume that only one kin...
Article
Majority-voting and the Condorcet Jury Theorem pervade thinking about collective decision-making. Thus, it is typically assumed that majority-voting is the best possible decision mechanism, and that scenarios exist where individually-weak decision-makers should not pool information. Condorcet and its applications implicitly assume that only one kin...
Article
Full-text available
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 6 three-spined sticklebacks, Gasterosteus aculeatus, containing 0, 2, 4...
Article
Collective intelligence refers to the ability of groups to outperform individuals in solving cognitive tasks. Although numerous studies have demonstrated this effect, the mechanisms underlying collective intelligence remain poorly understood. Here, we investigate diversity in cue beliefs as a mechanism potentially promoting collective intelligence....
Article
Full-text available
Diagnosing the causes of low back pain is a challenging task, prone to errors. A novel approach to increase diagnostic accuracy in medical decision making is collective intelligence, which refers to the ability of groups to outperform individual decision makers in solving problems. We investigated whether combining the independent ratings of chirop...
Data
Effect of group size on the Youden’s index, sensitivity and specificity for reading lumbosacral spine MR images (study 2) using classification B. Histograms show the frequency distributions of the improvement of groups under the majority rule as compared to the average individual performance of that group, in terms of (A) the Youden’s index, (B) se...
Data
Effect of group size on the Youden’s index, sensitivity and specificity for reading lumbosacral spine MR images (study 2) using classification A and B when excluding the six ambiguous cases for which the expert panel could not find consensus. Histograms show the frequency distributions of the improvement of groups under the majority rule as compare...
Data
Data sets Kurvers et al. 2018. The two data sets used in this study. (XLSX)
Article
Full-text available
The pace-of-life syndrome (POLS) hypothesis posits that life-history characteristics, among individual differences in behavior, and physiological traits have coevolved in response to environmental conditions. This hypothesis has generated much research interest because it provides testable predictions concerning the association between the slow-fas...
Preprint
Full-text available
Individual foraging is under strong natural selection. Yet, whether individuals differ consistently in their foraging success across environments, and which individual and population-level traits might drive such differences, is largely unknown. We addressed this question in a field experiment, conducting over 1,100 foraging trials with nine subpop...
Article
Full-text available
The costs and benefits of group living often depend on the spatial position of individuals within groups and the ability of individuals to occupy preferred positions. For example, models of predation events for moving prey groups predict higher mortality risk for individuals at the periphery and front of groups. We investigated these predictions in...
Article
Background: Evidence suggests that pooling multiple independent diagnoses can improve diagnostic accuracy in well-defined tasks. We investigated whether this is also the case for diagnostics in emergency medicine, an ill-defined task environment where diagnostic errors are rife. Methods: A computer simulation study was conducted based on empiric...
Article
Full-text available
Collective cognition has received much attention in recent years but most of the empirical work has focused on comparing individuals and groups within single populations, thereby not addressing evolutionary origins of collective cognition. Here, we investigated collective cognition in multiple populations that are subject to different levels of pre...
Article
Lateralization is widespread throughout the animal kingdom [1-7] and can increase task efficiency via shortening reaction times and saving on neural tissue [8-16]. However, lateralization might be costly because it increases predictability [17-21]. In predator-prey interactions, for example, predators might increase capture success because of speci...
Article
Full-text available
[ Proc. R. Soc. B 283 , 20161671 (Published online 2 November 2016). ([doi:10.1098/rspb.2016.1671][2])][2] There was a mismatch between the units reported for the base metabolic rate, c , in [figure 3][2] c in [[1][3]] and the corresponding units in the main text and labels of [figure 3][2] a , b
Article
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Billfishes are considered to be among the fastest swimmers in the oceans. Previous studies have estimated maximum speed of sailfish and black marlin at around 35 m s(-1) but theoretical work on cavitation predicts that such extreme speed is unlikely. Here we investigated maximum speed of sailfish, and three other large marine pelagic predatory fish...
Article
Full-text available
Collective intelligence refers to the ability of groups to outperform individual decision makers when solving complex cognitive problems. Despite its potential to revolutionize decision making in a wide range of domains, including medical, economic, and political decision making, at present, little is known about the conditions underlying collectiv...
Article
Full-text available
Personality differences are widespread throughout the animal kingdom and can have important ecological and evolutionary consequences. Despite a rapidly increasing body of literature, large (marine) vertebrates remain underrepresented in personality research. Given their unique life history traits (e.g. slow growth rate, slow reproduction rate, long...
Article
Full-text available
We present evidence of a novel form of group hunting. Group hunting sailfish (Istiophorus platypterus) alternate attacks on their schooling prey (Sardinella aurita). While only 23% 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 qu...
Article
Full-text available
Collective intelligence refers to the ability of groups to outperform individual decision-makers. At present, relatively little is known about the mechanisms promoting collective intelligence in natural systems. We here test a novel mechanism generating collective intelligence: self-organization according to information quality. We tested this mech...
Article
Importance Incidence rates of skin cancer are increasing globally, and the correct classification of skin lesions (SLs) into benign and malignant tissue remains a continuous challenge. A collective intelligence approach to skin cancer detection may improve accuracy.Objective To evaluate the performance of 2 well-known collective intelligence rule...