Rationality in decision-making in the fringe-lipped bat, Trachops cirrhosus
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Most models of animal behavior assume rationality in animal’s decisions, with animals maintaining strict preferences for different options (e.g., optimal foraging theory). In the wild, however, animals often choose among several options simultaneously, and their evaluation of each prey type may depend on the perceived relative values of other choices. Fringe-lipped bats (Trachops cirrhosus) are promising subjects for studying how animals make decisions. When given a choice between the calls of two species of frogs, T. cirrhosus will choose the more salient call that is associated with the higher capture rate. Although in the wild T. cirrhosus often choose among multiple call options, most tests of prey preferences in this system include only two options. In this experiment, we tested whether T. cirrhosus alters relative preference for two call types that differ along two acoustic dimensions (amplitude and complexity) when presented with a third, “decoy” option, inferior to the two original options along either one or both dimensions. Results from this study demonstrate that under these circumstances, T. cirrhosus evaluates all three options independently of one another, and thus, preferences remain consistent and rational in both the presence and absence of a decoy. These results counter many other experiments suggesting irrationality in animal decision-making.
A fundamental assumption of animal behavior is that animals make rational decisions. However, most animals are tested in ways that rely on simple binary choice experiments. Because animals are often faced with multiple options simultaneously in the wild, these tests may often fail to capture the complexity necessary to understand cognitive limitations that naturally influence animal decisions. In certain cases, complex decisions can result in irrational behavior that is inconsistent with what is found in binary choice studies. Here, we conducted a test with fringe-lipped bats to determine whether their choices for specific frog calls were influenced by the number of options in a choice set. We found that, unlike many other animals, the fringe-lipped bats appear to make consistent decisions, even with more complex choice sets. Our results indicate that there are likely to be strong selective pressures on rational decision-making in this species, perhaps shaped by high metabolic requirements.
KeywordsBats Túngara frogs Rationality Regularity Decoy effect Decision-making
We thank the Smithsonian Tropical Research Institute for assistance with permits and logistics. This research was approved by the Smithsonian Tropical Research Institute (STRI IACUC protocol 2014-0101-2017) and the University of Texas, Austin (AUP-2015-00048) and by the Government of Panama (Ministerio de Ambiente permit SE/A 69-15). Special thanks to Paige Johnson, Dallas Miller, and Sebastian Stockmaier for help with capture and caring for bats. We are grateful to Cindy Blanco for her statistical advice and to Stephen Pratt and two other anonymous reviewers for their insightful comments on the manuscript. CTH was funded by fellowship support from the Smithsonian Tropical Research Institute.
Compliance with ethical standards
All authors of this manuscript have read and agree on the content. There are no known financial or nonfinancial conflicts of interest with reviews recommended for this manuscript. All experiments were licensed and approved by the Smithsonian Tropical Research Institute (STRI IACUC protocol 2014-0101-2017) and the University of Texas, Austin (AUP-2015-00048) and by the Government of Panama (Ministerio de Ambiente permit SE/A 69-15). This article does not contain any studies with human participants performed by any of the authors. This work was funded by a Smithsonian Tropical Research Institute Short-term Fellowship Award.
- Ariely D (2010) Predictably irrational: the hidden forces that shape our decisions. New York Harper Perennial, New YorkGoogle Scholar
- Fleming TH (1986) The structure of Neotropical bat communities: a preliminary analysis. Rev Chilena Hist Nat 59:135–150Google Scholar
- Ghose K, Moss CF (2006) Steering by hearing: a bat’s acoustic gaze is linked to its flight motor output by a delayed, adaptive linear law. J Neurol 26:1704–1710Google Scholar
- Luce RP (1959) Individual choice behaviour: a theoretical analysis. Wiley, New YorkGoogle Scholar
- McCleery RH (1978) Optimal behavior sequences and decision making. In: Krebs JR, Davies NB (eds) Behavioral ecology: an evolutionary approach. Sinauer Associates, Sunderland, Massachusetts, pp 377–410Google Scholar
- Ryan MJ (1985) The túngara frog: a study in sexual selection and communication. University of Chicago Press, ChicagoGoogle Scholar
- Ryan MJ, Rand AS (1981) The adaptive significance of a complex vocal repertoire in a neotropical frog. Z Tierpsychol 57:209–214Google Scholar
- Ryan MJ, Tuttle MD (1987) The role of prey-generated sounds, vision, and echolocation in prey localization by the African batCardioderma cor (Megadermatidae). J Comp Physiol A 161(1):59–66Google Scholar
- Schuck-Paim C, Pompilio L, Kacelnik A (2004) State-dependent decisions cause apparent violations of rationality in animal choice. PLoS Biol 12:e402Google Scholar
- Shettleworth S (2010) Cognition, evolution, and behavior. Oxford University Press, OxfordGoogle Scholar
- Stephens DW, Krebs JR (1986) Foraging theory. Princeton University Press, PrincetonGoogle Scholar