Cognitive performance of dusky damselfish in a detour task with increasing difficulty.

Cognitive performance in animals can be assessed through the detour task, which challenges spatial navigation, decision-making, and behavioral flexibility. The most common versions of the detour task often fail to involve processing of different environmental cues, the adjusting of behavior to varying obstacles, and motivation, factors that are likely important for cognitive performance. In this study, we aimed to validate a new method for assessing cognitive performance—a detour task with increasing levels of difficulty—using the reef fish Stegastes fuscus. We evaluated the ability of individuals to traverse a 150 cm-long tank in which barriers with doors were progressively introduced across test days, increasing task complexity and requiring flexible detour strategies. Two groups were tested: one with a conspecific as a social stimulus and one without any stimulus. The results revealed that S. fuscus employed different behavioral strategies to complete the task, suggesting spatial learning, route planning, and possible memory use, especially when the social stimulus was present. This novel detour paradigm highlights the species’ cognitive capacity to solve progressively complex spatial challenges. Understanding how stimulus respond to increasing task demands provides valuable insights into animal cognition and behavioral ecology.