Switching costs in stochastic environments drive the emergence of matching behaviour in animal decision-making through the promotion of reward learning strategies

Nan Lyu,Yunbiao Hu,Yi Tao,Yue-Hua Sun,Huw Lloyd,Jiahua Zhang

doi:10.1038/s41598-021-02979-5

Abstract

A principle of choice in animal decision-making named probability matching (PM) has long been detected in animals, and can arise from different decision-making strategies. Little is known about how environmental stochasticity may influence the switching time of these different decision-making strategies. Here we address this problem using a combination of behavioral and theoretical approaches, and show, that although a simple Win-Stay-Loss-Shift (WSLS) strategy can generate PM in binary-choice tasks theoretically, budgerigars (Melopsittacus undulates) actually apply a range of sub-tactics more often when they are expected to make more accurate decisions. Surprisingly, budgerigars did not get more rewards than would be predicted when adopting a WSLS strategy, and their decisions also exhibited PM. Instead, budgerigars followed a learning strategy based on reward history, which potentially benefits individuals indirectly from paying lower switching costs. Furthermore, our data suggest that more stochastic environments may promote reward learning through significantly less switching. We suggest that switching costs driven by the stochasticity of an environmental niche can potentially represent an important selection pressure associated with decision-making that may play a key role in driving the evolution of complex cognition in animals.

Highlights

A principle of choice in animal decision-making named probability matching (PM) has long been detected in animals, and can arise from different decision-making strategies
PM can occur by adopting the simple WSLS strategy, we found that our budgerigars were more likely to adopt the comparatively more complex reward learning
Evidence from studies that examined relatively larger-brained birds exposed to more variable environments (e.g. Ref.36) and which have examined how environmental enrichment can promote the cognitive ability in fishes (e.g. Ref.37) did not provide any direct causation mechanisms

Summary

Introduction

A principle of choice in animal decision-making named probability matching (PM) has long been detected in animals, and can arise from different decision-making strategies. Little is known about how environmental stochasticity may influence the switching time of these different decisionmaking strategies We address this problem using a combination of behavioral and theoretical approaches, and show, that a simple Win-Stay-Loss-Shift (WSLS) strategy can generate PM in binary-choice tasks theoretically, budgerigars (Melopsittacus undulates) apply a range of sub-tactics more often when they are expected to make more accurate decisions. That adopting PM can be ‘ecologically rational’ if animals’ regularly encounter a situation in stochastic environments where PM is sufficient for reaching an immediate or short-term goal[13] Helping to resolve this debate requires a combined theoretical and empirical assessment of why animals adopt non-maximizing behavior, and identifying the conditions under which PM becomes beneficial in highly stochastic environments. A number of studies have considered such costs in decision-making, little is known about how environmental stochasticity may influence the switching time of different strategies, and potentially drive the evolution of different decision-making strategies

Methods

Results

Conclusion