Trial-History and Spatial Biases Shape Perceptual Decision-Making in Archerfish

Abstract

Identifying conserved principles of animal decision-making requires comparisons across evolutionarily distant species with divergent neuroanatomy. Yet teleost fish, an evolutionarily distant vertebrate lineage lacking a laminated cortex, are rarely studied using behavioral paradigms directly comparable to those used in mammals and birds. Here, we bridge this gap by exploiting the unique hunting behavior of archerfish to investigate determinants of decision-making. We trained archerfish to report their choices by shooting a jet of water at the selected visual target in a series of two-alternative choice tasks. We found that archerfish decisions are influenced by trial-history and spatial-biases, remarkably similar to those observed in mammalian and avian models. Specifically, subjects exhibited an outcome-history in the form of stay/switch behaviors, alongside a stimulus-history bias, in which they repeatedly selected the same shape across trials. Yet, unlike rodents, archerfish maintained stable behavior during unrewarded probe trials. Thus, our findings reveal that several fundamental determinants of choice previously characterized primarily in mammals are also present in teleost fish, suggesting that important components of vertebrate decision-making are conserved despite substantial divergence in brain organization and ecology. Simultaneously, the distinct response of archerfish to reward omission highlights species-specific differences in how animals adapt to changing environmental contingencies.