scholarly journals High-magnitude innovators as keystone individuals in the evolution of culture

2018 ◽  
Author(s):  
Michal Arbilly
Keyword(s):  
Population Dynamics ◽  
Food Webs ◽  
Computer Simulations ◽  
Cultural Evolution ◽  
Keystone Species ◽  
Low Frequency ◽  
Independent Innovation ◽  
High Magnitude ◽  
Behavioural Repertoire

AbstractBorrowing from the concept of keystone species in ecological food webs, a recent focus in the field of animal behaviour has been keystone individuals: individuals whose impact on population dynamics is disproportionally larger than their frequency in the population. In populations evolving culture, such may be the role of high-magnitude innovators: individuals whose innovations are a major departure from the population’s existing behavioural repertoire. Their effect on cultural evolution is twofold: they produce innovations that constitute a ‘cultural leap’, and, once copied, their innovations may induce further innovations by conspecifics (socially induced innovations), as they explore the new behaviour themselves. I use computer simulations to study the co-evolution of independent innovations, socially induced innovations, and innovation magnitude, and show that while socially induced innovation is assumed here to be less costly than independent innovation, it does not readily evolve. When it evolves, it may in some conditions select against independent innovation and lower its frequency, despite it requiring independent innovation in order to operate; at the same time, however, it leads to much faster cultural evolution. These results confirm the role of high-magnitude innovators as keystones, and suggest a novel explanation for low frequency of independent innovation.

scholarly journals High-magnitude innovators as keystone individuals in the evolution of culture

2018 ◽  
Vol 373 (1743) ◽  
pp. 20170053 ◽  
Author(s):  
Michal Arbilly
Keyword(s):  
Cultural Evolution ◽  
Keystone Species ◽  
Low Frequency ◽  
Interdisciplinary Studies ◽  
Theme Issue ◽  
Independent Innovation ◽  
High Magnitude ◽  
Cultural Gaps ◽  
Behavioural Repertoire

Borrowing from the concept of keystone species in ecological food webs, a recent focus in the field of animal behaviour has been keystone individuals: individuals whose impact on population dynamics is disproportionally larger than their frequency in the population. In populations evolving culture, such may be the role of high-magnitude innovators: individuals whose innovations are a major departure from the population's existing behavioural repertoire. Their effect on cultural evolution is twofold: they produce innovations that constitute a ‘cultural leap' and, once copied, their innovations may induce further innovations by conspecifics (socially induced innovations) as they explore the new behaviour themselves. I use computer simulations to study the coevolution of independent innovations, socially induced innovations and innovation magnitude, and show that while socially induced innovation is assumed here to be less costly than independent innovation, it does not readily evolve. When it evolves, it may in some conditions select against independent innovation and lower its frequency, despite it requiring independent innovation in order to operate; at the same time, however, it leads to much faster cultural evolution. These results confirm the role of high-magnitude innovators as keystones, and suggest a novel explanation for the low frequency of independent innovation. This article is part of the theme issue ‘Bridging cultural gaps: interdisciplinary studies in human cultural evolution'.

More Modules

2011 ◽  
Author(s):  
Kevin S. McCann
Keyword(s):  
Population Dynamics ◽  
Food Webs ◽  
Empirical Evidence ◽  
Intraguild Predation ◽  
Weak Interactions ◽  
Apparent Competition ◽  
Trade Offs ◽  
Variable Population ◽  
The Stability

This chapter considers four-species modules and the role of generalism (effectively a three-species module with a consumer feeding on two resources). It first examines how generalists affect the dynamics of food webs by focusing on a set of modules that contrast generalist consumer dynamics relative to the specialist case. It then discusses organismal trade-offs that play a role in governing the diamond food web module and the intraguild predation module, arguing that such tradeoffs influence the flux of matter, the organization of interaction strengths, and ultimately the stability of communities. The chapter also reviews empirical evidence showing that apparent competition and the diamond module with and without intraguild predation are ubiquitous, and that weak interactions in simple modules seem to promote less variable population dynamics.

scholarly journals Calculating the Unknown. Rationalities of Operational Risk in Financial Institutions

2010 ◽  
Vol 8 (2) ◽  
pp. 237-250
Author(s):  
Hajo Greif ◽  
Matthias Werner
Keyword(s):  
Information Technology ◽  
Risk Perception ◽  
Financial Crisis ◽  
Financial Institutions ◽  
Low Frequency ◽  
Risk Category ◽  
Operational Risks ◽  
High Magnitude ◽  
Risk Analysis And Management

In this paper, findings of a study on the perception and policing of information-technology (ICT) related operational risks are presented, with a view on identifying some part of the role that these technologies, and the specific organisational settings in which they are embedded, may have played in the making of the 2007+ financial crisis. The study’s findings concern, firstly, biases in risk perception that turn a blind eye towards certain operational risks; secondly, competing, qualitative vs. quantitative norms and methods of risk analysis and management and their significance for the governance of financial institutions; and thirdly, the role of ICTs as organisational technologies that work both as sources and as remedies of operational risks. The use of ICTs in financial institutions, it is concluded, while not being fully acknowledged in its organisational role, caters to the calculative rationality to which the analysis, management and governance of operational and other risks are increasingly subjected. Presuming that all kinds of risk can be made calculable and computable, this calculative rationality either misses out or obscures one important risk category: low frequency/ high magnitude risks, which tend to cross the boundary between calculable risk and genuine uncertainty of knowledge.

scholarly journals Calculating the Unknown. Rationalities of Operational Risk in Financial Institutions

2010 ◽  
Vol 8 (2) ◽  
pp. 237-250 ◽  
Author(s):  
Hajo Greif ◽  
Matthias Werner
Keyword(s):  
Information Technology ◽  
Risk Perception ◽  
Financial Crisis ◽  
Financial Institutions ◽  
Low Frequency ◽  
Risk Category ◽  
Operational Risks ◽  
High Magnitude ◽  
Risk Analysis And Management

In this paper, findings of a study on the perception and policing of information-technology (ICT) related operational risks are presented, with a view on identifying some part of the role that these technologies, and the specific organisational settings in which they are embedded, may have played in the making of the 2007+ financial crisis. The study’s findings concern, firstly, biases in risk perception that turn a blind eye towards certain operational risks; secondly, competing, qualitative vs. quantitative norms and methods of risk analysis and management and their significance for the governance of financial institutions; and thirdly, the role of ICTs as organisational technologies that work both as sources and as remedies of operational risks. The use of ICTs in financial institutions, it is concluded, while not being fully acknowledged in its organisational role, caters to the calculative rationality to which the analysis, management and governance of operational and other risks are increasingly subjected. Presuming that all kinds of risk can be made calculable and computable, this calculative rationality either misses out or obscures one important risk category: low frequency/ high magnitude risks, which tend to cross the boundary between calculable risk and genuine uncertainty of knowledge.

Refining our understanding of the “elephant in the room”

2020 ◽  
Vol 43 ◽  
Author(s):  
Andrew Whiten
Keyword(s):  
Social Cognition ◽  
Cultural Evolution ◽  
Cognitive Abilities ◽  
Critical Factors ◽  
Technological Culture

Abstract The authors do the field of cultural evolution a service by exploring the role of non-social cognition in human cumulative technological culture, truly neglected in comparison with socio-cognitive abilities frequently assumed to be the primary drivers. Some specifics of their delineation of the critical factors are problematic, however. I highlight recent chimpanzee–human comparative findings that should help refine such analyses.

Calculation-and-experimental estimation of the role of the frequency ratio in changing the endurance at two-frequency deformation modes

2019 ◽  
Vol 85 (1(I)) ◽  
pp. 64-71 ◽  
Author(s):  
M. M. Gadenin
Keyword(s):  
High Frequency ◽  
Experimental Studies ◽  
Low Frequency ◽  
Reduction Factor ◽  
Single Frequency ◽  
Cyclic Loads ◽  
Small Ratio ◽  
Harmonic Components ◽  
Deformation Modes

The cycle configuration at two-frequency loading regimes depends on the number of parameters including the absolute values of the frequencies and amplitudes of the low-frequency and high-frequency loads added during this mode, the ratio of their frequencies and amplitudes, as well as the phase shift between these harmonic components, the latter having a significant effect only with a small ratio of frequencies. Presence of such two-frequency regimes or service loading conditions for parts of machines and structures schematized by them can significantly reduce their endurance. Using the results of experimental studies of changes in the endurance of a two-frequency loading of specimens of cyclically stable, cyclically softened and cyclically hardened steels under rigid conditions we have shown that decrease in the endurance under the aforementioned conditions depends on the ratio of frequencies and amplitudes of operation low-frequency low-cycle and high-frequency vibration stresses, and, moreover, the higher the level of the ratios of amplitudes and frequencies of those stacked harmonic processes of loading the greater the effect. It is shown that estimation of such a decrease in the endurance compared to a single frequency loading equal in the total stress (strains) amplitudes can be carried out using an exponential expression coupling those endurances through a parameter (reduction factor) containing the ratio of frequencies and amplitudes of operation cyclic loads and characteristic of the material. The reduction is illustrated by a set of calculation-experimental curves on the corresponding diagrams for each of the considered types of materials and compared with the experimental data.

scholarly journals Do males matter? The role of males in population dynamics

Oikos ◽  
2007 ◽  
Vol 116 (2) ◽  
pp. 335-348 ◽  
Author(s):  
Daniel J. Rankin ◽  
Hanna Kokko
Keyword(s):  
Population Dynamics

scholarly journals High Ripple-Density Resolution for Discriminating Between Rippled and Nonrippled Signals: Effect of Temporal Processing or Combination Products?

2021 ◽  
Vol 25 ◽  
pp. 233121652110101
Author(s):  
Dmitry I. Nechaev ◽  
Olga N. Milekhina ◽  
Marina S. Tomozova ◽  
Alexander Y. Supin
Keyword(s):  
Low Frequency ◽  
Noise Signal ◽  
Density Variation ◽  
Choice Procedure ◽  
Masker Level ◽  
Reference Signals ◽  
Forced Choice Procedure ◽  
The Mean ◽  
Density Resolution

The goal of the study was to investigate the role of combination products in the higher ripple-density resolution estimates obtained by discrimination between a spectrally rippled and a nonrippled noise signal than that obtained by discrimination between two rippled signals. To attain this goal, a noise band was used to mask the frequency band of expected low-frequency combination products. A three-alternative forced-choice procedure with adaptive ripple-density variation was used. The mean background (unmasked) ripple-density resolution was 9.8 ripples/oct for rippled reference signals and 21.8 ripples/oct for nonrippled reference signals. Low-frequency maskers reduced the ripple-density resolution. For masker levels from −10 to 10 dB re. signal, the ripple-density resolution for nonrippled reference signals was approximately twice as high as that for rippled reference signals. At a masker level as high as 20 dB re. signal, the ripple-density resolution decreased in both discrimination tasks. This result leads to the conclusion that low-frequency combination products are not responsible for the task-dependent difference in ripple-density resolution estimates.

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