scholarly journals A Simple Model for the Evolution of Evolution

1997 ◽  
Vol 05 (03) ◽  
pp. 341-357 ◽  
Author(s):  
Siegfried Fussy ◽  
Gerhard Grössing ◽  
Herbert Schwabl
Keyword(s):  
Simple Model ◽  
Cognitive Abilities ◽  
Background Noise ◽  
Feedback Loop ◽  
Fitness Landscape ◽  
Fundamental Property ◽  
Dependent Measure ◽  
Intrinsic Fluctuations ◽  
Discretized Systems ◽  
Additional Feedback

A simple model of macroevolution is proposed exhibiting both the property of punctuated equilibrium and the dynamics of potentialities for different species to evolve towards increasingly higher complexity. It is based on the phenomenon of fractal evolution which has been shown to constitute a fundamental property of nonlinear discretized systems with one memory- or random-based feedback loop. The latter involves a basic "cognitive" function of each species given by the power of distinction of states within some predefined resolution. The introduction of a realistic background noise limiting the range of the feedback operation yields a pattern signature in fitness space with a distribution of temporal boost/mutation distances according to a randomized devil's staircase function. Introducing a further level in the hierarchy of the system's rules, the possibility of an adaptive evolutionary change of the resolution itself is implemented, thereby providing a time-dependent measure of the species' cognitive abilities: an additional feedback loop makes use of the inevitable intrinsic fluctuations within the fitness landscape to direct the temporal change of the resolution. Feeding back the small adaptive changes of resolution into the essentially directionless variations of the patterns' lifetimes in fitness space effectively leads to a clear tendency towards increasing evolution potentials for each species ("hierarchically emergent fractal evolution").

DIFFUSION OF A POPULATION OF INTERACTING REPLICATORS IN SEQUENCE SPACE

2002 ◽  
Vol 05 (04) ◽  
pp. 457-461 ◽  
Author(s):  
BÄRBEL M. R. STADLER
Keyword(s):  
Simple Model ◽  
Population Size ◽  
Computer Simulations ◽  
Mutation Rate ◽  
Sequence Space ◽  
Finite Population ◽  
Fitness Landscape ◽  
Diffusion Constant ◽  
Sequence Length

We consider a simple model for catalyzed replication. Computer simulations show that a finite population moves in sequence space by diffusion analogous to the behavior of a quasispecies on a flat fitness landscape. The diffusion constant depends linearly on the per position mutation rate and the ratio of sequence length and population size.

Coupled-Oscillator Model of Locomotion Stability With Elastically-Suspended Loads

2011 ◽  
Author(s):  
Jeffrey Ackerman ◽  
Justin Seipel
Keyword(s):  
Simple Model ◽  
Energy Cost ◽  
Fundamental Property ◽  
Suspended Load ◽  
Oscillator Model ◽  
Rough Terrain ◽  
Stability Of Motion ◽  
Coupled Oscillator ◽  
Coupled Oscillator Model ◽  
Suspended Loads

Elasticity is a fundamental property of dynamic locomotion and is generally thought to affect the efficiency and stability of motion. In particular, it is becoming increasingly apparent that elastically-suspended loads are common in biology and useful for carrying loads. For example, the Suspended Load Backpack reduces the peak forces and energy cost during locomotion. In this paper, we present a simple model of locomotion to examine the effect of elastically-suspended loads on the peak forces, energy cost, and stability during locomotion. The results from the model show that elastically-suspended loads reduce the peak forces, energy cost, and stability of locomotion compared to rigidly-attached loads, thus indicating that a tradeoff exists between the decreased stability of locomotion and the reduction of peak forces and energy cost. We discuss this tradeoff and the implications of reduced stability on locomotion over rough terrain and the maneuverability of a system.

EXPRESS: Lending a Hand to Storytelling: Gesture’s Effects on Narrative Comprehension Moderated by Task Difficulty and Cognitive Ability

2021 ◽  
pp. 174702182110249
Author(s):  
Nicola McKern ◽  
Nicole Dargue ◽  
Naomi Sweller ◽  
Kazuki Sekine ◽  
Elizabeth Austin
Keyword(s):  
Cognitive Ability ◽  
Verbal Memory ◽  
Cognitive Abilities ◽  
Background Noise ◽  
Task Difficulty ◽  
Intellectual Ability ◽  
Narrative Comprehension ◽  
Compelling Evidence ◽  
Iconic Gesture ◽  
Interference Background

Compelling evidence suggests observing iconic gestures benefits learning. While emerging evidence suggests typical iconic gestures benefit comprehension to a greater extent than atypical iconic gestures, it is unclear precisely when and for whom these gestures will be most helpful. The current study investigated factors that may moderate when and for whom gesture benefits narrative comprehension most, including the type of gesture, task difficulty, and individual differences in cognitive ability. Participants were shown a video narrative in which they observed either typical gestures (commonly produced gestures, highly semantically related to accompanying speech), atypical gestures (gestures that are seldom produced), or no gestures. The video narrative was either viewed with interference (background noise to increase task difficulty) or no interference (no background noise). To determine whether the effects of gesture observation and externally imposed task difficulty on narrative comprehension further depend on an individual’s cognitive abilities, participants completed four measures of cognitive abilities (immediate and delayed non-verbal memory, attention, and intellectual ability). Observing typical gestures significantly benefited narrative comprehension compared to atypical and no gestures combined, which did not differ significantly. Participants with below average and average levels of delayed non-verbal memory benefited more from typical gestures than atypical or no gestures compared to those with an above average level of delayed non-verbal memory. However, this interaction was only significant when the task was difficult (i.e., with interference) but not when the task was simple (i.e., no interference). This finding suggests that the type of iconic gesture observed may impact gesture’s beneficial effect on narrative comprehension, and that such gestures may be more beneficial in difficult tasks, but only for certain individuals.

scholarly journals Modeling the interplay between plastic tradeoffs and evolution in changing environments

2019 ◽  
Author(s):  
Mikhail Tikhonov ◽  
Shamit Kachru ◽  
Daniel S. Fisher
Keyword(s):  
Simple Model ◽  
Environmental Exposure ◽  
Minimal Model ◽  
Genetic Background ◽  
Evolutionary History ◽  
Feedback Loop ◽  
Explicit Dependence ◽  
Evolutionary Modeling ◽  
Changing Environments ◽  
Simple Models

Performance tradeoffs are ubiquitous in both ecological and evolutionary modeling, yet are usually postulated and built into fitness and ecological landscapes. But tradeoffs depend on genetic background and evolutionary history, and can themselves evolve. We present a simple model capable of capturing the key feedback loop: evolutionary history shapes tradeoff strength, which, in turn, shapes evolutionary future. One consequence of this feedback is that genomes with identical fitness can have different evolutionary properties, shaped by prior environmental exposure. Another is that, generically, the best adaptations to one environment may evolve in another. Our minimal model highlights the need for analysis of simple models capable of incorporating explicit dependence on environment, and can serve as a rich playground for investigating evolution in multiple or changing environments.

scholarly journals A model for the interplay between plastic tradeoffs and evolution in changing environments

2020 ◽  
Vol 117 (16) ◽  
pp. 8934-8940 ◽  
Author(s):  
Mikhail Tikhonov ◽  
Shamit Kachru ◽  
Daniel S. Fisher
Keyword(s):  
Simple Model ◽  
Environmental Exposure ◽  
Genetic Background ◽  
Evolutionary History ◽  
Feedback Loop ◽  
Geometric Model ◽  
Evolutionary Modeling ◽  
Changing Environments

Performance tradeoffs are ubiquitous in both ecological and evolutionary modeling, yet they are usually postulated and built into fitness and ecological landscapes. However, tradeoffs depend on genetic background and evolutionary history and can themselves evolve. We present a simple model capable of capturing the key feedback loop: evolutionary history shapes tradeoff strength, which, in turn, shapes evolutionary future. One consequence of this feedback is that genomes with identical fitness can have different evolutionary properties shaped by prior environmental exposure. Another is that, generically, the best adaptations to one environment may evolve in another. Our simple framework bridges the gap between the phenotypic Fisher’s Geometric Model and the genotypic properties, such as modularity and evolvability, and can serve as a rich playground for investigating evolution in multiple or changing environments.

scholarly journals PERIOD–TIMELESS Interval Timer May Require an Additional Feedback Loop

2007 ◽  
Vol 3 (8) ◽  
pp. e154 ◽  
Author(s):  
Robert S Kuczenski ◽  
Kevin C Hong ◽  
Jordi García-Ojalvo ◽  
Kelvin H Lee
Keyword(s):  
Feedback Loop ◽  
Interval Timer ◽  
Additional Feedback

scholarly journals Human self-domestication and the evolution of pragmatics

2020 ◽  
Author(s):  
Antonio Benítez-Burraco ◽  
Francesco Ferretti ◽  
Ljiljana Progovac
Keyword(s):  
Cognitive Abilities ◽  
Feedback Loop ◽  
Driving Forces ◽  
Language Evolution ◽  
Reactive Aggression ◽  
Cognitive Disorders ◽  
Supporting Evidence ◽  
Gradual Process ◽  
Turn Taking ◽  
Key Aspects

As proposed for the emergence of modern languages, we argue that modern uses of languages (pragmatics) also evolved gradually in our species under the effects of human self-domestication, with three key aspects involved in a complex feedback loop: (i) a reduction in reactive aggression, (ii) the sophistication of language structure (with emerging grammars initially facilitating the transition from physical aggression to verbal aggression); and (iii) the potentiation of pragmatic principles governing conversation, including, but not limited to, turn-taking and conversational implicature. Our core hypothesis is that the reduction in reactive aggression, one of the key factors in self-domestication processes, enabled us to fully exploit our cognitive and interactional potential as applied to linguistic exchanges, and ultimately, to evolve sophisticated turn-taking, as well as complex inferential abilities, both of which seem to require fine-tuned coordination and cooperation. Supporting evidence for our proposal, as well as grounds for further testing, comes mainly from the consideration of cognitive disorders, which typically simultaneously present abnormal features of self-domestication, including aggressive behavior, and problems with pragmatics and social functioning. While various approaches to language evolution typically reduce it to a single factor, our approach considers language evolution as a multifactorial process, with each player acting upon the other, engaging in an intense mutually reinforcing feedback loop. Moreover, we see language evolution as a gradual process, continuous with the pre-linguistic cognitive abilities, which we also see as engaged in a positive feedback loop with linguistic innovations, with gene-culture co-evolution and cultural niche construction as the main driving forces.

Is an Automaker's Road to Bankruptcy Paved with Customers' Beliefs?

2011 ◽  
Vol 101 (3) ◽  
pp. 93-97 ◽  
Author(s):  
Ali Hortaçsu ◽  
Gregor Matvos ◽  
Chaehee Shin ◽  
Chad Syverson ◽  
Sriram Venkataraman
Keyword(s):  
Simple Model ◽  
Financial Distress ◽  
Feedback Loop ◽  
Multiple Equilibria ◽  
Debt Service ◽  
Financial Health ◽  
Stylized Facts ◽  
Bank Run ◽  
On Demand ◽  
The Impact

We explore the role the feedback loop between firms' financial health and consumers' demand for their products plays in the auto market. We construct a simple model of an automaker making pricing and debt service (continuation) decisions while recognizing that consumers are sensitive to whether it stays in business. We show that multiple equilibria can exist in such a model, and calibrate it to match stylized facts surrounding GM's recent bankruptcy. The results suggest that while the impact of financial distress on demand substantially reduced GM's profit, bank-run-like multiple equilibria do not appear likely in this market.

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