Archerfish number discrimination

Abstract

Debates have arisen as to whether non-human animals actually can learn astract non-symbolic numerousness or whether they always rely on some continuous physical aspect of the stimuli covarying with number. Here we investigated archerfish (Toxotes jaculatrix) non-symbolic numerical discrimination with accurate control for co-varying continuous physical stimulus attributes. Archerfish were trained to select one of two groups of black dots (Exp. 1: 3 vs. 6 elements; Exp. 2: 2 vs. 3 elements); these were controlled for several combinations of physical variables (elements' size, overall area, overall perimeter, density and sparsity), ensuring that only numerical information was available. Generalization tests with novel numerical comparisons (2 vs. 3, 5 vs. 8 and 6 vs. 9 in Exp. 1; 3 vs. 4, 3 vs. 6 in Exp. 2) revealed choice for the largest or smallest numerical group according to the relative number that was rewarded at training. None of the continuous physical variables, including spatial frequency, were affecting archerfish performance. Results provide evidence of the spontaneous use of abstract relative numerical information in archerfish for both small and large numbers.

Magnitudes for Nervous Systems: Theoretical Issues and Experimental Evidence

“…Although some researchers (e.g., Leibovich et al, 2017) have argued that it may be difficult to disentangle animals’ ability to assess discrete quantity from their ability to assess confounding continuous quantities, accurate controls of continuous physical variables in some investigations have made it possible to conclude that animals can estimate pure discrete quantity (numerosity; see, e.g., Potrich et al, 2022, which is noteworthy in that the role of spatial frequency was also controlled for). The idea of a neat separation of discrete from continuous magnitudes seems to go hand in hand with the idea that selectivity to discrete quantities (numerosities) would be apparent only at later stages of processing, in pallial (cortical) areas of the brain, whereas selectivity to the size of stimuli and other continuous quantities would be apparent already at earlier stages, in subpallial (subcortical) areas.…”

Introduction: Trends, Puzzles, and Hopes for the Future of Healthcare

“…15. Deeply exploring the fields of neuroscience, cognitive science, and perception, which are rife with puzzles (Ekroll et al, 2016;Gallistel, 2021;Hulse et al, 2021;Langille & Gallistel, 2020;Potrich et al, 2022;Robinson & Brandon, 2021). Let us take one example: when writing on motor planning, Emilio Bizzi and Robert Ajemian pose the following question: "how is an evanescent wish to move translated into a concrete action?…”