Is optimism optimal? Functional causes of apparent behavioural biases

Area of Science:

• Animal behavior
• Evolutionary biology
• Decision theory

Background:

• The terms 'optimism' and 'pessimism' are frequently used to describe animal behavior.
• Existing literature provides numerous examples of animals exhibiting seemingly optimistic or pessimistic actions.
• However, the application of these terms often lacks clear definition and can lead to confusion.

Purpose of the Study:

• To critically review the usage of 'optimism' and 'pessimism' in characterizing non-human animal behavior.
• To evaluate the appropriateness of these terms within the framework of optimal decision theory.
• To clarify common misunderstandings and propose a more precise application of these behavioral descriptors.

Main Methods:

• Literature review of studies using 'optimism' and 'pessimism' in animal behavior.
• Analysis of animal behavior through the lens of optimal decision theory and relevant currencies.
• Application of bandit models to understand long-term optimal strategies versus short-term apparent biases.

Main Results:

• The terms 'optimism' and 'pessimism' are often poorly defined in the context of animal behavior.
• Misidentification of currencies and payoffs can lead to misinterpretations of animal decision-making.
• Behaviors appearing suboptimal in the short term may be optimal for long-term survival and are better explained by models like bandit theory.

Conclusions:

• 'Optimism' and 'pessimism' are better restricted to informal descriptions of animal behavior.
• Accurate prediction of natural selection requires careful consideration of the relevant currency being maximized.
• A rigorous approach using decision theory and appropriate models offers a clearer understanding of animal behavior than subjective terms.