Color preferences affect learning in zebrafish, Danio rerio

Tamal Roy,Jennifer Flores,Collin Hickey,Emília P Martins,Piyumika S Suriyampola,Anuradha Bhat,Melissa López

doi:10.1038/s41598-019-51145-5

Abstract

Animals may exhibit preference for colors that match their environment or the resources in the environment. These preferences may impact ability to learn associations with these colors and revert the associations when the reward contingency is modified. We used zebrafish Danio rerio from four populations to test if color preferences impact associative and reversal learning ability. First, we tested if preference for blue or green impact associative ability. We subjected individual fish through eight trials to associate a social stimulus with blue or green. Next, we tested if preference for red or green impact associative reversal learning ability. We trained fish in groups of three to associate a social stimulus with red or green over three trials, and reversed the reward contingency during the following session. Results showed that zebrafish preferred green over blue and domesticated fish chose green more than blue when there was a reward attached. Zebrafish also preferred red over green. Fish from one wild population learned with both colors and reversed learning only from green to red and not vice-versa. Fish from another population showed an overwhelming preference for red irrespective of what was rewarded. Domesticated fish did not show reversal learning ability.

Highlights

Color preferences may impact learning, and the extent of this impact may depend on the type of learning as well as on the developmental and evolutionary history of the animals
We focused on simple associative learning with a blue or green stimulus, and asked whether zebrafish from different populations differed in both their preferences for these colors and their ability to learn an appetitive task using these stimuli
In the initial color preference tests, wild-caught zebrafish in our study entered a green door rather than a blue door first, whether those fish were from populations A (Green: 69%, Blue: 31%; χ21 = 4.5, n = 32, p = 0.03), B (Green: 69%, Blue: 31%; χ21 = 3.8, n = 26, p = 0.05) or C (Green: 69%, Blue: 31%; χ21 = 3.8, n = 25, p = 0.05)

Summary

Introduction

Color preferences may impact learning, and the extent of this impact may depend on the type of learning as well as on the developmental and evolutionary history of the animals. The impact of color preferences on learning may depend on the specific type of learning Animals differ in their cognitive flexibility, with some being more limited than others in their abilities to reverse learning[6,7]. The ability to modify a previously learned experience and develop a new one allows animals to cope with complex or predictable but rapidly changing environments[20]. This reversal learning has been well documented in several species like guppies Poecilia reticulata[20], Pinyon jays Gymnorhinus cyanocephalus, scrub jays Aphelocoma californica and nutcrackers Nucifraga columbiana[21], jumping spiders Marpissa muscosa[22]. Though inter-population studies on associative learning are common, variation in reversal learning across populations has received less attention (see review by[6])

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Discussion

Conclusion