Design and evaluation of a series of experimental procedures to investigate cognition in fish at early developmental stages and in adulthood ​

This thesis had two main objectives. The first was to explore cognitive development in zebrafish larvae using reliable and rapid testing methods. The aim was to develop/adjust methodologies that are accessible and easily replicable across various scientific laboratories and disciplines, responding to the increasing demand for interdisciplinary research on zebrafish cognition. The initial part of the research examined discriminative and associative learning, along with numerical cognition, providing insights into the cognitive development of zebrafish larvae. The second part investigated working memory in guppies (Poecilia reticulata) by utilizing adaptations of the matching-to-sample (MTS) paradigm in both its simultaneous (SMTS) and delayed (DMTS) forms, with the intention of expanding experimental frameworks for studying numerical cognition in this species. The findings revealed that the cognitive tests applied to zebrafish larvae could be effectively transferred to fields beyond comparative psychology, although some limitations were noted. Group housing during associative learning delayed the assessment of individual learning, and the rapid neural development of zebrafish larvae necessitated shorter experimental protocols. Moreover, spontaneous preferences were observed, varying significantly with the subjects’ age, highlighting a key factor influencing cognitive performance in zebrafish. In guppies, while the SMTS task revealed consistent learning, the DMTS task presented challenges due to procedural limitations. In summary, the thesis highlights the potential of these cognitive tests for broader scientific application, offering a valuable foundation for interdisciplinary research on animal cognition. While the methodologies show promise, the need for refinement remains critical for optimizing their utility across different species and research contexts.