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Assessment of Mouse Judgment Bias through an Olfactory Digging Task
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Published on: March 4, 2022

Environmental variability can select for optimism or pessimism.

John M McNamara1, Pete C Trimmer, Anders Eriksson

  • 1School of Mathematics, University of Bristol, University Walk, Bristol BS8 1TW, UK. john.mcnamara@bristol.ac.uk

Ecology Letters
|November 13, 2010
PubMed
Summary

Reproductive biases like optimism and pessimism can evolve through natural selection. Environmental factors, specifically dispersal rates between populations, determine whether optimism or pessimism is favored for long-term lineage growth.

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Area of Science:

  • Evolutionary biology
  • Behavioral ecology
  • Population dynamics

Background:

  • Natural selection optimizes long-term lineage growth, not short-term reproductive success.
  • Biases in evaluating environmental events, termed reproductive optimism and pessimism, can appear irrational but may be evolutionarily favored.
  • Understanding the evolution of these biases requires considering population structure and environmental stochasticity.

Purpose of the Study:

  • To define reproductive optimism and pessimism operationally.
  • To investigate the evolutionary pressures favoring optimism or pessimism in a metapopulation model.
  • To determine the role of environmental structure in shaping evolved reproductive biases.

Main Methods:

  • Developed a metapopulation model to simulate population dynamics and evolution.
  • Defined optimism as over-weighting positive events and pessimism as over-weighting negative events in reproductive decisions.
  • Analyzed the impact of varying dispersal rates and environmental stochasticity on the evolution of these biases.

Main Results:

  • Optimism is favored when dispersal is high, leading to independent environmental influences across subpopulations.
  • Pessimism is favored when dispersal is low, causing correlated environmental fluctuations within subpopulations.
  • The spatial and temporal structure of the environment critically influences the direction of evolved biases.

Conclusions:

  • Reproductive optimism and pessimism are evolutionarily viable strategies shaped by natural selection.
  • Environmental factors, particularly dispersal rates, are key determinants of whether optimism or pessimism prevails.
  • These findings highlight the importance of considering population structure in understanding the evolution of behavioral strategies.