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Brain morphology predicts social intelligence in wild cleaner fish.
Zegni Triki1,2, Yasmin Emery3, Magda C Teles4
1Institute of Biology, University of Neuchâtel, Emile-Argand 11, 2000, Neuchâtel, Switzerland. zegni.triki@gmail.com.
Nature Communications
|December 22, 2020
Summary
In wild cleaner fish, brain structure varies with social density, suggesting ecological factors influence cognitive performance and intelligence. Larger forebrains in high-performing individuals indicate social competence is key to understanding natural intelligence.
Area of Science:
- Evolutionary biology
- Neuroscience
- Animal behavior
Background:
- Brain anatomy variation is linked to environmental complexity and intelligence.
- The impact of ecology on brain plasticity and cognitive performance within species is not well understood.
Purpose of the Study:
- To investigate how ecological factors, specifically social density, affect brain anatomy and cognitive performance in wild cleaner fish (Labroides dimidiatus).
- To explore the relationship between brain size, social competence, and decision-making strategies in a natural setting.
Main Methods:
- Wild cleaner fish were assessed using an ephemeral reward task to measure cognitive performance.
- Forebrain and cerebellum sizes were measured and correlated with cleaner fish density.
Main Results:
- Individuals with higher performance in the reward task showed a positive correlation between forebrain size and cleaner density.
- Cerebellum size showed a negative correlation with cleaner density in high-performing individuals.
- Performance in the task was interpreted as reflecting natural decision-making rules rather than pure learning ability.
Conclusions:
- Social competence, indicated by forebrain size, appears to be a reliable proxy for intelligence in wild cleaner fish.
- Ecological factors like social density significantly influence brain structure and cognitive strategies in natural populations.
- Decision-making rules used by individuals may be more indicative of intelligence under natural conditions than traditional learning assessments.
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